The 68-Special from Tippmann Pneumatics Inc : 2013

Sunday, June 9, 2013

The Parts List.

PENDING UPDATE

Picture will be updated to show more variants and Siphon Tank parts as well as updated part details that I will update when possible. As for availability and price, these were last checked Oct of 2014.

Model 68-SPECIAL Parts List

This is the last revision of the 68-Special design. I included the original release as well. Too many parts to include conversions. The initial release was very much like the one shown in the manual. With improvements on the fly, and upgrades on older versions retaining the previous serial number, a definite tie of version to serial number is not possible. Despite all changes, if your marker has part #02 (Front Upper Receiver Casting), then you have a 68 Special regardless of what the nameplate says. Note that Milky Urethane o-rings have a 5 year shelf life and Buna o-rings have a 15 year shelf life. The 68-Special is over 20 years old. Change your o-rings...

This is a compiled parts list for the marker and the sources where they are available. I have not purchased from all these sites but their specs match the original parts. Due to lack of data, the o-ring hardness had to be guessed based on its use in the marker. I will note confirmation on ordered parts as I get them. Part #'s are not Tippmann #'s, Tippmann identified their parts by name only at the time. I randomly chose numbers and added the SP68 prefix as shown below. I also expanded and updated the owners manual tear-down drawing for the parts list. Measurements were pulled from limited documents and measuring of existing parts on my markers. Parts are identified as Stock match - should be the same as original, Equivalent replacement - some difference, usually material but should work, and Deluxe part - should out perform original part. I would also recommend Urethane o-rings over Buna but do remember that they have a 5 year shelf life, Buna have a 15 year shelf life, great for emergency spares. Listed pricing does not include shipping and was current as of 04/2013. Prices from PB sports current as of 06/08/2013. I cannot guarantee fit as Markers varied through construction and/or upgrades as well as sellers description accuracy and specs can change. All effort has been taken shy of purchasing for accuracy. This page will be updated as information is gathered or corrected. This page is still not complete.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

*** BIG NEWS ***

http://www.baccipaintball.com

Is selling used and new parts for the 68-Special.
They will not be listed below as part availability, condition, and price varies with each part. Be sure to read all descriptions as some parts have damage listed. Order placed 08/17/2013. Received. Highly recommend this source. Has some New old-stock as well.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

68SP01 - Tippmann ID: Lower Receiver Casting

Tippmann part : Replacement: parts salvage only.

68SP01B - Tippmann ID: Lower Receiver Casting (Early style with no milling for part 04)

Tippmann part : Replacement: parts salvage only.

68SP02 - Tippmann ID: Front upper Receiver Casting
Tippmann part : Replacement: parts salvage only.

68SP03 - Tippmann ID: Receiver Bolts [2 total]
Socket Button Head Receiver retaining bolts 5/16"-24 x 3/4" [2 total] (Note that originals have been ground shorter by 1/16" to avoid hitting front bolt.)
Part is Available from http://www.boltdepot.com/ (read warning)
Warning - These must be ground shorter by 1/16" to avoid hitting and damaging front bolt.
Stock match (read warning)
Socket button head, Alloy steel black oil finish, 5/16"-24 x 3/4" Bolt Depot Product #:13227 $0.18 ea
Deluxe Stainless (read warning)
Socket button head, Stainless steel 18-8, 5/16"-24 x 3/4" Bolt Depot Product # 5730 $0.76 ea

68SP04 - Tippmann ID: Gun Valve Spacer
Tippmann part : Actually the valve retainer plate,
Listed as still available at PB sports. (Tippmann 68 Special Valve Spacer $4.95) Note: I puchased one
and it would not fit, it was too small, may be filed.
Specs pending for home fabrication

68SP05 - Tippmann ID: End Cap Srew [1 total]
Set screw, #10-32 x 3/16" Original appears to be plain steel or zinc plated steel.
Part is Available from http://www.boltdepot.com/
Equivalent Replacement
Set screw, Allen, Cup point, Alloy steel black oil finish, #10-32 x 3/16" Product # 8486 $0.07 ea
Deluxe Stainless
Set screws, Allen, Cup point, Stainless steel 18-8, #10-32 x 3/16" Bolt Depot Product #: 7019 $0.10 ea
Listed as still available at PB sports. (Tippmann 68 Special End Cap Screw $0.95)

68SP06 - Tippmann ID: Receiver Tube with Safety
Tippmann part : Replacement: parts salvage only

68SP06 - Tippmann ID: Receiver Tube (Early style on markers with or without part 04, No Safety)
Tippmann part : Replacement: parts salvage only

68SP07 - Tippmann ID: End Cap
Tippmann part : I am sure this is a hydraulic part and there is a match or an equivalent, searching.
Listed as still available at PB sports. (Tippmann 68 Special End Cap $14.95)

68SP08 - Tippmann ID: Receiver Roll Pins [3 total]
Steel roll pins 1/8 x 3/4"
Part is Available from http://www.fastenermart.com/
Stock match
PN116-0192 1/8 x 3/4" Spring Pin, Plain Finish (no rust protection), $3.83 pkg/100 pcs
Deluxe Stainless
PN166-4292 1/8 x 3/4" Spring Pin, Stainless Steel, $6.72 pkg/100 pcs

68SP09 - Tippmann ID: Rear Bolt
Tippmann part : Replacement: parts salvage only

68SP10 - Tippmann ID: Rear Bolt O-Ring
AS568A Dash No. -020, 7/8" x 1 x 1/16" Black Buna (Milky urethane from factory) Duro 90
Part is Available from http://www.theoringstore.com/
Stock Match
020 U90 Urethane O-ring model U90020 $1.40 ea Recommended
020 B90 Buna-N Nitrile O-ring Model B90020 $0.15 ea

68SP11 - Tippmann ID: Bolt Handle
Tippmann part : Replacement: parts salvage only
Specs pending for home fabrication

68SP12 - Tippmann ID: Bolt Handle O-Ring
AS568A Dash No. -011, 5/16" x 7/16" x 1/16" - Black Buna Duro 70
Part is Available from http://www.theoringstore.com/
Stock Match
011 B70 Buna-N 70 O-ring Model B70011 $0.06 ea

68SP13 - Tippmann ID: Bolt Spring
Tippmann part : The Main spring is 4 lbs only but early models had a 2.5 lb spring. Summer and winter tensions refer to the SMG-60 line only. Read TIL report, there is
critical data on spring safety.
Listed as still available at PB sports. (Tippmann 68 Special Main Spring $3.95) Note: I puchased one
and it would not fit, not for the 68-Special, probably for the 98-custom.
Replacements may be available soon, pending specs details to a manufacturer.

68SP14 - Tippmann ID: Valve Body
Tippmann part : Replacement: parts salvage only. Note original SMG models are not compatible.
Machining required to adapt. Specs pending.

68SP14B - Tippmann ID: Valve Body (Early style not milled for part 04, retained with part 08)
Tippmann part : Replacement: parts salvage only.

68SP15 - Tippmann ID: Bolt Spring Rod
Tippmann part : Main Spring Stabilizing Rod
Listed as still available at PB sports. (Tippmann 68 Special Bolt Spring Rod $5.95) Note: I puchased
one and it would work for the 68-Special.

68SP16 - Tippmann ID: Front Bolt
Tippmann part : Moulded plastic part made only for the 68-Special
Listed as still available at PB sports. (Tippmann 68 Special Front Bolt $9.95)

68SP17 - Tippmann ID: Bolt Linkage Arm
Tippmann part : Replacement: parts salvage only
Specs pending for home fabrication

68SP18 - Tippmann ID: Ball Latch
Tippmann part : Replacement: parts salvage only

68SP19 - Tippmann ID: Front Bolt O-Ring

This one has been a challenge. Some kits had Duro90 and some Duro70. To reduce the friction damage from sand and dirt, I am changing this to the softer Duro 70.
AS568A Dash No. -015, 9/16" x 11/16" x 1/16" Black Buna Duro 70
Part is Available from http://www.theoringstore.com/
Stock Match
015 U70 Urethane O-ring Model: U70015 $1.15 ea (Factory)
015 B70 Buna-N 70 O-ring Model B70015 $0.15 ea

68SP20 - Tippmann ID: Ball Latch Spring
Tippmann part : Light Spring
Listed as still available at PB sports. (Tippmann 68 Special Ball Latch Spring $1.95)
Replacements may be available soon, pending specs details to a manufacturer.

68SP21 - Tippmann ID: Ball latch Roll Pin [2 total]
Steel roll pins 3/32 x 3/4" [2 total]
Part is Available from http://www.fastenermart.com/
Stock Match
PN146-9132 3/32 x 3/4" Spring Pin, Plain Finish (no rust protection), $3.12 pkg/100pcs
Stainless not available in this size and length.

68SP22 - Tippmann ID: Power Tube & Bushing
Tippmann part : Replacement: parts salvage only

68SP22B - Tippmann ID: Power Tube & Bushing (Early style with steel pin across center)
Tippmann part : Replacement: parts salvage only

68SP23 - Tippmann ID: Power Tube Bushing O-Ring
AS568A Dash No. -116, 3/4" x 15/16" x 3/32" - Black Buna Duro 70
Part is Available from http://www.theoringstore.com/
Stock Match
116 B70 Buna-N 70 O-ring Model: B70116 $0.08 ea

68SP24 - Tippmann ID: Velocity Adjuster Screw
Velocity Adjustment Screw Late generation original appears to be plain zinc plated steel and early generation black oil finish, both with one 3/16" spot of red threadlock compound, 1/8" from cup (inside)
Part is Available from http://www.boltdepot.com/
Equivalent Replacement
Set screws,Allen,Cup point,Alloy steel black oil finish,#10-32 x 1/2" Bolt Depot Product #: 8491 $0.08ea
Deluxe Stainless
Set screws, Allen, Cup point, Stainless steel 18-8, #10-32 x 1/2" Bolt Depot Product #: 7023 $0.09 ea

68SP25 - Tippmann ID: Valve O-Ring
AS568A Dash No. -020, 7/8" x 1" x 1/16" - Black Buna (Milky urethane from factory) Duro 90
Part is Available from http://www.theoringstore.com/
Stock Match
020 B90 Buna-N Nitrile O-ring Model: B90020 $0.15 ea
020 U90 Urethane O-ring Model: U90020 $1.40 ea Recommended

68SP26 - Tippmann ID: Valve Spring
Appears to be a stainless heavy spring
Listed as still available at PB sports. (Tippmann 68 Special Valve Spring $1.95)
Replacements may be available soon, pending specs details to a manufacturer.

68SP27 - Tippmann ID: Valve Seats [2 total]
Tippmann part : Brass
Listed as still available at PB sports. (Tippmann 68 Special Valve Seat $9.95) or in (Tippmann 68
Special Valve Rebuild Kit $29.95)

68SP28 - Tippmann ID: Valve Plungers [ 2 total]
Tippmann part : Brass and Stainless
Listed as still available at PB sports. (Tippmann 68 Special Valve Plunger $9.95) or in (Tippmann 68
Special Valve Rebuild Kit $29.95)

68SP29 - Tippmann ID: Valve Snap Ring [2 total]
Standard fastener : specs and alternate source pending
Listed as still available at PB sports. In (Tippmann 68 Special Valve Rebuild Kit $29.95)

68SP30 - Tippmann ID: Valve "Seat" O-Rings [2 total]
AS568A Dash No. -012, 3/8" x 1/2" x 1/16" - Factory Urethane Duro 70 (Though shown in TIL documents as Black Buna, I verified that later models have factory Urethane. Better for liquid CO2 contact.)
Part is Available from http://www.theoringstore.com/
Stock match
012 U70 Urethane O-ring Model: U70012 $0.41 ea Recommended
012 B70 Buna-N 70 O-ring Model: B70012 $0.06 ea

68SP31 - Tippmann ID: Valve Elbow
Micro plumbing part : Searching for source

68SP32 - Tippmann ID: Valve Elbow "Flathead" Furrow
Micro plumbing part : Searching for source
Listed as still available at PB sports. In (Tippmann 68 Special Gas Line Kit $11.95)

68SP33 - Tippmann ID: Internal Gas Line Tubing
Nylotube Nylon -12 part # 233 0216 Semi-rigid Grade: ID 0.075", OD 0.125", Wall .025", WORKING
PSI AT 70°F 1000 PSI, BURST PSI AT 70°F 3000 PSI, BEND RADIUS 0.25", Shore Hardness D ±5 72, Cold Impact Resistance -40°F, Max. Operating Temp. 212°F
Sold as 500' spool
New Age Industries
145 James Way
Southampton, PA 18966
www.newageindustries.com
Careful when buying microline as most are actually over 1/8" outside diameter. The flexible equivalent has too low of a burst rating.
Listed as still available at PB sports. In (Tippmann 68 Special Gas Line Kit $11.95)

68SP34 - Tippmann ID: Gas Line Inserts [2 total]
Micro plumbing part : Searching for source
Listed as still available at PB sports. In (Tippmann 68 Special Gas Line Kit $11.95)

68SP35 - Tippmann ID: Gas Line Spring
Tippmann part : Light spring to reinforce and protect gas tube.
Listed as still available at PB sports. In (Tippmann 68 Special Gas Line Kit $11.95)
Replacements may be available soon, pending specs details to a manufacturer.

68SP36 - Tippmann ID: Gas Line "Barrel" Furrow
Micro plumbing part : Searching for source
Listed as still available at PB sports. In (Tippmann 68 Special Gas Line Kit $11.95)

68SP37 - Tippmann ID: Hex Nut for Gun Valve Elbow
Micro plumbing part :

68SP38 - Tippmann ID: Rear Gas Line Fitting (silver)
Tippmann part :
Listed as still available at PB sports. (Tippmann 68 Special Rear Gas Line Fitting $3.95)

68SP39 - Tippmann ID: Trigger (Semi-Auto)
Tippmann part : Replacement: parts salvage only

68SP40 - Tippmann ID: Trigger Spring
Tippmann part : Replacement: parts salvage only
Replacements may be available soon, pending specs details to a manufacturer.

68SP41 - Tippmann ID: Sear
Tippmann part : Replacement: parts salvage only

68SP42 - Tippmann ID: Sear Spring
Tippmann part : Replacement: parts salvage only
Replacements may be available soon, pending specs details to a manufacturer.

68SP43 - Tippmann ID: Barrel Screw [1 total]
Socket cap, Alloy steel black oil finish, 1/4"-20 x 3/4"
Part is Available from http://www.boltdepot.com/
Stock match
Socket cap, Alloy steel black oil finish, 1/4"-20 x 3/4" Bolt Depot Product #: 5026 $0.11 each
Deluxe Stainless
Socket cap, Stainless steel 18-8, 1/4"-20 x 3/4" Bolt Depot Product #: 4883 $0.18 each

68SP44 - Tippmann ID: Ammo Box & Pistol Grip Screw [2 total] 1/4" x 7/8"
Socket cap, Alloy steel black oil finish, 1/4"-20 x 7/8"
Part is Available from http://www.boltdepot.com/
Stock match
Socket cap, Alloy steel black oil finish, 1/4"-20 x 7/8" Bolt Depot Product #: 8029 $0.11 each
Deluxe Stainless
Socket cap, Stainless steel 18-8, 1/4"-20 x 7/8" Bolt Depot Product #: 5513 $0.20 each

68SP45 - Tippmann ID: 11" Standard Barrel Stock, 16" Sniper Barrel Available
Tippmann part : Replacement: parts salvage only, Both were aluminum with no porting or rifling. They are
non-threaded and held by the pinch bolt. Compatible with first generation SL 68 markers.
Pictures and specs pending.

68SP46 - Tippmann ID: Front Grip
Tippmann part : Replacement: parts salvage only

68SP47 - Tippmann ID: Rear Hand Grip
Lonestar Compartment Grip : Baccipaintball has new old-stock for $15.00 each

68SP48 - Tippmann ID: Cylinder pin Valve seal O-Ring
AS568A Dash No. -015, 9/16" x 11/16" x 1/16" White Teflon (Milky urethane from factory) Duro 90
Part is Available from http://www.theoringstore.com/
Stock match
015 U90 Urethane O-ring Model: U90015 $0.99 ea
015T PTFE White Teflon O-ring Model: TEF015 $0.96 ea (Place in hot water prior to placement
to reduce deformation and cuts.)

68SP49 - Tippmann ID: 7 oz Siphon Tank Stock, 20 oz Siphon Tank Available and recommended
Tippmann part : Replacement: parts salvage only (Unless damaged, the 7 oz tanks do not require
hydro-testing. The 20 oz does require testing every 5 years. Inspect and/or repair siphon tubes at this
time.)
Do you have a siphon tank? Hold the tank near the valve and swing it back and forth like a bell. If you hear something swinging and clanking inside, its a siphon tank. If it sounds like something rolling around, then the weight or tube is loose and must be repaired before use. Siphon tanks should be clearly marked with the word "SIPHON TANK". Using a siphon tank on a non-siphon marker can damage or destroy the marker.
Replacement Siphon tanks can be built. Watch for my future Blog. (Read Warning)
Warning - Modifications to CO2 tanks Should be completed by a Certified Airsmith for Safety
and Liability reasons. Improper valve assembly can fail or come apart creating life threatening conditions.

68SP50 - Tippmann ID: Butt Stock for 7 oz Cylinders
Tippmann part : Replacement: parts salvage only

68SP51 - Tippmann ID: NONE
Butt Stock Round Head Bolt 10-32 x 1/2" [2 total]
Tank Buttstock Pinch Machine Screws, #10-32 x 1/2" The stock screws may be alloy steel black oil
finished or blued steel. [2 total]
Part is Available from http://www.boltdepot.com/
Equivalent Replacement (These must painted black to match.)
Machine screws,Slotted round head, Zinc plated steel,#10-32 x 1/2" Bolt Depot Product# 1762 $0.05ea
Deluxe
Silicon Bronze Tank Buttstock Pinch Machine Screw, I chose these over stainless, as stainless to stainless
contact tends to gaul. [2 total]
Slotted round head, Silicon bronze, #10-32 x 1/2" Bolt Depot Product #: 3439 $0.40 each

68SP52 - Tippmann ID: NONE
Butt Stock Hex Nut 10-32 [2 total]
Part is Available from http://www.boltdepot.com/
Equivalent Replacement (These must painted black to match.)
Tank Buttstock Pinch Machine Nut, The stock nuts may be the alloy steel black oil finish or blued steel.
These must be painted black to match. [2 total]
Hex machine screw nuts, Zinc plated steel, #10-32 Bolt Depot Product #: 2646 $0.05 each
Deluxe
Silicon Bronze Tank Buttstock Pinch Machine Nut, I chose these over stainless, as stainless to stainless
contact tends to gall. [2 total]
Hex machine screw nuts, Silicon bronze, #10-32 Bolt Depot Product #: 3479 $0.24 each

68SP53 - Tippmann ID: Owners Manual (Not Shown on Drawing)
Tippmann part : Printed manual (Original)
Listed as still available at PB sports. (Tippmann 68 Special Manual $6.95)

68SP54 - Tippmann ID: O-ring Kit (Not Shown on Drawing)
O-ring replacement kit. Purchased one from PB sports and it looks new and good. Installed the o-rings using Tippmann certified oil and grease, worked perfectly.
Listed as still available at PB sports. (Tippmann 68 Special Oring Kit $10.95)

68SP55 - Tippmann ID: NONE
Sling (Not Shown on Drawing)
Nylon Webbing : Specs pending

68SP56 - Tippmann ID: NONE
Sling Buckles (Not Shown on Drawing)
Generic part : Specs pending

68SP57 - Tippmann ID: Tank fill Coupling (Not Shown on Drawing)
Plumbing part : Specs pending

68SP58 - Tippmann ID: Tank fill Coupling Seal (Not Shown on Drawing)
Nitrile or Buna Flat Washer : Specs pending

68SP59 - Tippmann ID: NONE
68 Special Iron-on Patch (Upper right on Drawing)
Tippmann part : Replacement: parts salvage only

68SP60 - Tippmann ID: Tank Rupture Disc O-rings [4 Total per tank] (Not Shown on Drawing)
AS568A Dash No. -008, 3/16" x 5/16" x 1/16" - Black Buna Duro 70
Part is Available from http://www.theoringstore.com/
Stock match
008 B70 Buna-N 70 O-ring Model: B70008 $0.06 ea

Note on O-rings: O-rings hardness is affected by temperature. The colder it is, the harder the material. For example- On the rear bolt seal Duro 90 would be optimal. Shore "A" scale is used on these o-rings. For use in colder climate, softer o-rings may be in order. A temperature vs hardness scale may helpful when selecting. There may likewise be an optimal hardness for Summer and Winter or Northern and Southern states. Factory levels are good starting points but environmental conditions will be the deciding factor. The usage chart in the TIL may be compared to the hardness characteristic chart to establish optimum selection. The up side is if you buy direct you can get the BEST for a fraction of the price for the mystery ring kits others are selling. Also if a vendor changes the Duro hardness between orders, You may not be told. This makes marker firing discrepancies and leaks hard to track and remedy.
SML
Blogger.com user StrayBlackCatsMeow

Address http://68-special.blogspot.com/
Blog "The 68-Special from Tippmann Pneumatics Inc"
Blog Reference page number 07
Title - The Parts List.
Revised - 06/18/22

Wednesday, April 3, 2013

68 Special Owners Manual

The Model 68-Special Operator's Manual

Sorry for the scan quality. I will post cleaner copies when I figure out the editor. If an image shows blank then try reloading this page. There are a few .pdf copies available on the web if you search. I am reluctant to link at this time due to issues I have with some of the other data posted on the sites. Maybe after I finished my blog and calmed down.

Blank

I am currently gathering together relevant CO2 technical documents to show the actual physics involved with this marker. The actual formula calculations will not be possible due to environmental and marker variables, but the concepts can be clarified. As of now I have not found a single web site that doesn't use "Dry CO2" data when referring to the operation of the 68 Special. I have even found a few that make me say WTF? It's obvious they have only used HPA electronic markers.

I don't like to be a cynic but we'll see how popular HPA becomes when atrophy begins showing itself on aging HPA systems. Considering that an old tire over inflated to 70 psi can kill you. Imagine the fun to be had with 3 to 4.5 thousand psi. Darwin awards are in the works for the ones that say " Get the compressor, Let's see if it still works!"

Ok, I vented, I feel much better now....

SML
Blogger.com user StrayBlackCatsMeow

Address http://68-special.blogspot.com/
Blog "The 68-Special from Tippmann Pneumatics Inc"
Blog Reference page number 05
Title - The Model 68-Special Operator's Manual
Revised - 08/22/13

Monday, April 1, 2013

TIL-SMGSPG

TECHNICAL INFORMATION LETTER - SMGSPG (121398)

Tippmann SMG Series, Bolt Main Springs

REVISION C - DESTROY ALL OTHER COPIES

OBSERVED PROBLEM: Pellet velocities other than stated for standard and high pressure bolt main springs. Varying velocities from similar main springs. Problem in identification of springs. Adjustment of gun velocities.

SOURCE OR CAUSE: Different steels, coil diameters, wire sizes, coil spacing, spring length, heat treatment and tensile strength,singly or in combination, will give different spring energies. The supplier's changing of a machine and/or machine operator between orders may also have an effect on each different lot of springs. A long spring may well be of a lower power than a short one.

In measuring the static energies of a particular set of springs in both standard and high pressure, we found that they varied from 2 1/2 to 3 pounds added energy in the standard, and 3 1/4 to 4 1/4 pounds in the high pressure. The averages were 2 3/4 pounds and 3 3/4 pounds. The maximum difference's between different lots of the same type were as much as thirty-five percent!

REPAIR OR PROBLEM REDUCTION: Simple measuring of the spring length or its superficial color will have no bearing on the spring energy as the factory can only specify an energy at a certain compression length to the supplier and take what they get. Springs normally cannot be identified by simple means.

The uncompressed length of the springs ranges from 180mm to 200mm. At the rest, or un-cocked bolt position, the spring is compressed to 137mm. In the armed, or cocked bolt position the spring is further compressed 50mm more to 87mm. The difference in measurement is not kinetic energy. When the bolt hits the gun valve body, it has gained a lot more force. It is however, sufficient for our purposes.

To measure yours, obtain a simple kitchen or mail scale which has a range of ten pounds or more. Slide the spring over a 1/8" rod of nine inches or more in length. If possible, thread a 6X32 nut on the end to keep the spring from forcing off the end and then bending upon release. Slide a 1/8" washer over the rod on top of the spring the a larger washer or spacer to gain grip. Place the nut end of the rod in the center of the scale top and with a metric ruler, compress the spring to 137mm. Read the weight from the scale. Continue compressing to 87mm and read the scale weight again. Subtract the 137mm reading from the 87mm reading. This is the static or added energy of the spring.

The above is all academic though. All guns are different. The prime rule in both internal and external ballistics is, "You can engineer the hell out of a weapons system, but you never know what it will do until after you pull the trigger." The moral is simple. Clean your gun, lube it, then take it out to your field's chronograph. That is the only way you will know what velocity that spring will give in that gun.

Before chronographing, wait until after the temperature of the gun, CO2 cylinder and paint have stabilized. Normalize your gas system with three shots pointed up in the air, and then shoot three round sequences holding the barrel level without pointing it down until done.Keep the muzzle well to the rear of the light cell to prevent falsing. Keep in mind that changes in the ambient temperature, and hence the CO2 pressure will vary velocities considerably. Guns equipped with an All Weather Tank will record higher velocities with the same spring. You should make a set of springs cut to different lengths.

To adjust spring energies, cut off several coils at a time and retest. Use nippers, not your side cutters if you value them. Do not attempt to increase the tension by stretching the spring. You will be torquing the wire coils beyond design specs and weakening them. The length will recede in time and the spring will have less energy than it started with. If you want more tension, order one or more high pressure springs and chronograph them to get the tension you desire. USE ONLY FACTORY SPRINGS! Spring design is very intricate. One that, "looks about right", may eventually damage the gun valve internals, receiver, or end cap threads. Cutting more than 10% of spring length may give erratic velocities. High pressure springs cannot be cut down far enough to equal a low pressure one.

To verify one claim that adding spring coils to a regular spring increased velocity, we conducted our own experiments. We found that very little extra spring can be added as there is only a small amount of available room. The additional spring coils crowding into this space resulted in a binding and over-compression of the springs, AND A NET LOSS OF ENERGY OF APPROXIMATELY 10%! Therefore, only a spring DESIGNED with a certain amount of energy, at a certain compression will work in the SMG Series of guns.

RELATED INFORMATION: All SMG-68's were equipped with the standard 2.5 lb. spring until late 1988. All are now equipped with the 4.0 lb. high pressure spring. Some guns sneaked thru with 5.0 lb. winter springs. These yield 400 fps in summer and are dangerous. SMG-68's and Special's normally only use a standard pressure spring. Springs must be kept very clean and well lubed, as they will wear from friction and lose energy over a period of time. See also TIL-GENVEL, TIL-SPCVEA, TIL-SMGCLN and TIL-SMGOIL.

This document is retyped from a low quality copy that was hard to read. I don't type but the information is so important that it had to be done. Note that because the 68s are liquid fed, seasonal spring changes are not needed. SML

Blogger.com user StrayBlackCatsMeow

Address http://68-special.blogspot.com/
Blog "The 68-Special from Tippmann Pneumatics Inc"
Blog Reference page number 04
Title - TIL-SMGSPG
Revised - 10/18/14

TIL-GENORID

INSTRUCTION SHEET - GENORID (030891)

Tippman O-Ring Identification and Use

REVISION B - DESTROY ALL OTHER COPIES

DISCUSSION: User trouble in identifying o-rings purchased in kits for Tippmanns Pneumatic's paintball guns, and in determining when to replace them or where to use them. See also TIL-SMGSEAL AND TIL-SMGOIL. Pneumatic Ordnance o-ring kits are total kits, comprising ALL the o-rings in the guns concerned. Certain kits have extra tank valve o-rings. Some o-rings are used less often than other's or only in specific situations. All are also sold separately or in packages of two.

One o-ring can have different uses in the same gun and unrelated uses in other models. It is therefore difficult to name them separately. They are identified by size, and are measured by their internal diameter and cross section thickness. The outer diameter is rarely used but is given here for ease of identification. The color, material, particular gun, service and probable usage rate are also listed for consumer information.

Whenever an o-ring is suspect, replace it without hesitation. Never attempt to salvage one, or try to determine if it is usable by eye or touch. These methods are unreliable and problem prone. Junk it for the slightest reason. Noeprene o-rings should not be used in conjunction with petroleum based oils or in high pressure conditions unless well restrained. Urethane tolerates oils and high pressure better but may be more expensive. Buna resists chemical attack very well, and is more cost effective than urethane. Teflon should not be used in sliding applications. Viton strikes a balance between rough service, attack and absorption. Liquid operation and using siphon cylinders may cause gas and gun valve seals to erode and leak sooner.

7/8" x 1" x 1/16" - Black Buna (Milky urethane from factory)
SMG60 1st Gen, SMG60 2nd Gen, SMG-68 and 68 Special - Used as main or rear bolt seal, and as gun valve ring seal. Low pressure and only under fire. High movement on bolt, moderate movement on gun valve ring, dirty environment. Moderate usage, replace at the beginning of season and more often if regular use or in dusty conditions. Set of two.

3/4" x 15/16" x 3/32" - Black Buna
68 Special Only - Used as power tube face seal. Low pressure and under fire. No movement, clean environment. Zero to low usage, replace only if lost or damaged. One o-ring.

5/8" x 3/4" x 1/16" - Black Buna
SMG60 1st Gen Only - Used as gun valve body seal. High and constant pressure. Moderate movement, clean environment. Moderate usage, replace at beginning of season, when in heavy use or whenever the gun valve is removed. Set of two.

9/16" x 11/16" x 1/16" White Teflon (Milky urethane from factory)
SMG60 1st Gen, SMG60 2nd Gen, SMG68, 68 Special and SL68 - Used as cylinder pin valve seal. High and constant pressure. Low movement but dirty environment and rough service. High usage if not kept clean and greased, or if cylinder is not inserted vertically. Clean, inspect and re-grease whenever cylinder is refilled. Replace instantly if the slightest imperfection is seen. Do not use black neoprene or buna. One o-ring, spares recommended.

9/16" x 11/16" x 1/16" - Black Buna
68 Special - Used as front bolt breech seal. Low pressure and only under fire. Moderate movement, dirty environment. Moderate usage, replace each season, more often if in regular use or in dusty conditions. One o-ring.
SL68 II - Used as receiver end cap seal. High and constant pressure. Low movement, but dirty environment and rough service. High usage if not kept clean and greased. One o-ring, spares recommended.
1/2" x 11/16" x 3/32" - Black Buna (Milky Urethane from factory)
SL68 Only - Used as bolt breech seal. Low pressure area and only when under fire. Moderate movement, dirty environment. Low usage, replace each season or if no compression is felt on closing bolt. One o-ring.

7/16" x 5/8" x 3/32" - Brown Viton (black neoprene or buna from factory)
CAM Constant Air Magnum Steel 4.5 and 9 Ounce CO2 Cylinders - Used for pin valve end seal. High and constant pressure. No movement, but dirty environment and rough service. High usage if not glued in with gasket cement. Buna or urethane o-rings will pop out easily from CO2 absorption and expansion on depressurization. Replace as necessary from loss or damage. Do not peen in, keep greased. One o-ring.

3/8" x 1/2" x 1/16" - Black Buna (Milky Urethane from factory for SL68 only)
SMG60 1st Gen, SMG60 2nd Gen, SMG68 and 68 Special - Used for gun valve plunger cup seals (gun valve plunger collars or seats). High and constant pressure area. no movement, clean environment. Low usage, replace if gun valve is disassembled or leaking. Easily damaged on removal of plunger. Do not mistake for plunger seal leakage. Set of two.
SL68 - Used for gas valve body seal. High and constant pressure area. Low movement, clean environment. Low usage on SL II, high on 1st gen. SL. Easily damaged on 1st gen SL68 valve removal. Do not mistake for valve seal leakage. One o-ring on 1st gen., two on SL68 II.

5/16" x 7/16" x 1/16" - Black Buna
68 Special Only - Used for retaining bolt link to bolt handle and front bolt arm. No pressure. Low usage, replace as necessary or if visibly damaged or worn. Set of two.

3/16" x 5/16" x 1/16" - Black Buna
SMG 1st Gen - Used for gas line elbow and gun valve screw (rear sight) seals. High and constant pressure. No movement, dirty environment. Low usage, replace if damaged or slow leaks develop. Set of three.
SMG60 2nd Gen, SMG68 and 68 Special - Used as packing for rear gas tube ferrule compression screw protrusion adjustment. High and constant pressure. No movement, clean environment. Zero to low usage, replace equal number when gas tube is replaced, add or remove as necessary to change protrusion of screw. One to three may be needed.
Tippmann Pneumatic's 3.5, 7 and 20 Ounce CO2 Cylinders - Used as pin valve rupture disk seal. High and constant pressure. No movement. clean environment. Low usage, replace whenever rupture disk is replaced. One o-ring.

5/32" x 7/32" x 1/32" - Black Buna
SMG60 1st Gen Only - Used for gas line screw seals. High and constant pressure. No movement, clean environment. Low usage, not available except when purchasing the entire gas line assembly. Use 3/16" x 1/4" x 1/32" o-rings with slight bevel on the edge of the screw hole, or automotive form-a-gasket compounds.

This document is retyped from a low quality copy that was hard to read. I don't type but the information is so important that it had to be done. SML

Blogger.com user StrayBlackCatsMeow

Address http://68-special.blogspot.com/
Blog "The 68-Special from Tippmann Pneumatics Inc"
Blog Reference page number 03
Title - TIL-GENORID
Revised - 08/22/13

68 Special: Out of the box Specifications

Tippmann Pneumatics 68 SPECIAL

Top half are the accessories that were available at the time: Stock Tippmann 20oz Siphon tank with generic buttstock, 100 Rnd Viewloader hopper (the biggest the store had but its expandable), Stock Tippmann Sniper Barrel, generic hopper adapter (painted pipe fitting). Shown in the lower half of the box is what you got. Owners manual, patch, spare O-rings, The 68 SPECIAL, 40 Rnd hopper, 7oz siphon tank, squeegee, sling and filler adapter with rubber washer. The marker with no accessories was purchased new in 1991 for $369.00+tax. This was their display marker, the 68 Specials were back-ordered with no scheduled delivery date. I can't remember what the accessories cost, they were purchased later. In those days stock Tippmann parts were expensive.
I have seen a number of recent 68 Special sales, all claiming to be in excellent condition, complete and original straight from the box. Most were actually in poor condition and damaged with ill fitted mods, as well as having non-Tippmann or missing original parts. I am posting this to show what really came in the box. Sorry, It's NOT FOR SALE, so please don't ask.

This is from the manual. Compare this to the ridiculous number of parts in modern markers. The earliest 68-Special design is shown on this diagram. Receiver tube is SMG-60 without the safety, the receiver is not yet milled for the valve retainer spacer which is not shown. Valve has not been milled for the valve retainer spacer. Trigger is SMG-60 Gen2. Power tube is of first run design.. There is a roll pin under valve from SMG-60 Gen2 on this model. I have rendered from this diagram an accurate exploded view and parts list of the last model that I will upload at a later date.

Specifications of the Tippmann 68 SPECIAL

Caliber:........................................................................................................68
Power:.................................................................CO2 (7 oz. siphon cylinder)
Mag. Capacity...........................................................................................50+
CO2 Capacity..............................................................225 shots per cylinder
Cycle Rate:......................................................................................300 RPM
Standard Barrel Length.............................................................................11"
Length-Overall:..........................................................................................32"
Weight:....................................................................................................4.8 lb.
Effective Range:..................................................................................150+ ft.
Action:..........................................................Semi-auto (open bolt blow-back)
Tippmann Stock SNIPER Barrel Length...................................................16"

One thing to consider along with the roundness quality when selecting paint is the paint ball diameter size and size consistency. The 68 cal paintballs vary in size depending on the manufacturers or brands. They can range from .684" to .694". Modern paintball markers favor the smaller size. These can result in lower velocities, poor accuracy, and breakage issues in the 68 Special. The optimum size for consistent velocity and accuracy is .692". Charts are available on the net to check the nominal sizes of the brands your field carries for the best selection.

Due to the nature of the liquid CO2 "Wet System" , After the tank is installed and before paintballs are added at the chronograph station. The marker should be pointed upward and rapidly fired three to four times to "wet the system" (remove all gas from the lines and valve). This puts the marker at its maximum velocity for chronograph purposes. [Note that doing this with a dry CO2 marker will temporarily lower the velocity, a primary difference in the two systems.] Most likely your field will not be familiar with wet systems and rather than argue the fact chronograph the first seven shots, the last three being your velocity. Been there. done that.
To save on tank seals when removing a still charged tank. Unscrew the tank 3/4 turn, invert marker to dump balls from feedneck back to hopper and fire marker in a safe direction. It will fire three to four times with remaining CO2 in the receiver The bolt will remain closed when empty. The tank can then be removed without the hiss and O-ring damage. Lube the o-ring for longer life.

I am posting on this site the only two Technical Information Letters from Tippmann that I have found so far, TIL-SMGSPG and TIL-GENORID. These Refer to all early Tippmann markers but contain extremely useful information on the 68 Special's main spring and O-rings. I wish I had these when I bought my marker, I probably didn't need to replace the valve seats, only the o-rings. If anyone is aware of the location of the following TILs, Please direct me to them in comments so I can get and post them. The needed TILs are:
TIL-GENVEL

TIL-SMGCLN
TIL-SMGOIL
TIL-SMGSEAL

TIL-SPCVEA < This one is of great interest as it may supply extremely useful information on the 68 Specials velocity adjustment system.The others may have useful references.

I copied my owners manual and will soon be posting it after I crop and size the scans.

SML

Blogger.com user StrayBlackCatsMeow

Address http://68-special.blogspot.com/
Blog "The 68-Special from Tippmann Pneumatics Inc"
Blog Reference page number 03
Title - 68 Special: Out of the box Specifications
Revised - 08/22/13

Sunday, March 31, 2013

The Serendipitous Paintball Marker

My 68 Special with Tippmanns stock 16 inch sniper barrel, 20oz tank, 100 round Viewloader vl-90v2 loader, Palmers SHER085 muzzle brake, Tyler #3 trigger shoe, generic buttstock and padded rifle sling. Missing in this picture is the Aimpoint 5000 2X red dot scope with grooved receiver mounts. When fully loaded, it is heavy. It's length is almost the width of the car. The best 1992 Woodsball Marker.

The Model 68 Special from Tippmann Pneumatics Inc.

The Serendipitous Paintball Marker

I am writing this due to the lack of available information on what I consider one of the best and unique paintball markers ever made. The Tippmann 68 Special was a marker ahead of its time and then abruptly abandoned. My goal is to try to fill in the gaps and clear up misunderstandings about the Wet CO2 system markers compared to standard Dry CO2 system markers, Something that I wish Tippmann had done. Had they tried, they might have realized what they had and what could have been done with it. I also hope that the information I can provide will increase interest in and help to return the 68 Special to the field of play. Look out Mil Sims, Old school is pushing back. So here is my blog of what I discovered was the Serendipitous Paint Marker, the 68 SPECIAL. Enjoy.

An advertisement for the 68 Special in paintball magazines

Though very reliable and durable in the field, the 68 Special had two Achilles heals.

The first was a production issue. The 68 Specials started by hand assembling from chopped pre-made SMG 68 frames and toolings. These were hand fitted to a chopped SL-68 style feed and barrel system. This meant that the markers had slight variations and did not have easy interchangeability where it was most critical for the evolution of the marker to take place. Even when the markers were being hand greensand cast dedicated for the 68-Special, it still restrained the much of the cut and fit construction of the original. SMG 60 conversions had more delicate frames and the receiver could not stand up to the increased forces generated by the use of liquid CO2. Some cracked at the setscrew on the receiver tube support. Others just cracked at the forward bolt hole locations that remained after the conversion. The pinch was made exclusively for the SL-68's 40 rnd hopper, Not the standard hoppers that were on the market. The pinch would break if someone attempted to force a fit.

The second was that much of the material it was made of rusted. Most of the markers of the time were aluminum, brass, and/or plastic. After a game it was typical to rinse and hang the markers to dry. Soap that washed off the oil based paint also washed off the protective oil coat on the Tippmanns. This was also true of its SMG predecessors. That is the main reason functioning markers are getting harder to find. You will notice the brown receiver sleeves and hammers on most markers that come up for sale, rust damage. I fortunately owned real weapons and was used to detail cleaning and oiling, so my markers were well regulated [Kept in good working order, if your unfamiliar with the term.] I will be using pictures of them in my discussions. Yes I do have more than one.

The greatest and most unique feature of this Marker was the push into Wet Systems Technology. Most likely accidental while studying a flaw in the SMG series, accidental liquid feed. A feature that was turned from a liability to an asset. A marker that did not suffer the chill effect of rapid fire even while spitting frozen vapor itself. A marker with no regulator yet could maintain safe velocities where others failed and still fail. A marker that could rival HP Air markers decades before they even existed. Then suddenly, abandoned. Never to be raised to reach its full potential, but left to fade out of existence because its parent chose to dote over a less perplexing child, the SL.

I have since determined that despite being the greatest feature, liquid feed was also THE death knell for the 68 Special. Tippmann's failure to change the design on the Siphon tank valve allowed the siphon tanks to be used on non-siphon markers. This became more painfully obvious when they were being used with factory SMG-60s. The SMG-60 was only COMPATIBLE AFTER the mainspring was clipped, a fact never listed in any manual. Its use on other markers proved more disastrous. The liability was high. Rather then draw attention to the issue, the 68 line was quietly dropped and all replacement parts sold off. At the time of this writing, Tippmann still does not have copies of the owners manual for the 60's or 68's on its web site. You will also find no mention of siphon tanks.

The New Beginning

If you plan to acquire a 68 SPECIAL for play you will need a Full face mask with a soft flexible chin and cheek area that will flex around the tank. The 68 Special shoulder mounts high like a real rifle. Rigid masks will not let you look down the sites. The 1990 masks were smaller and did not have the clearance problem. I use a JT Proteus mask with my markers and it has just enough give to sight in.

1990 field legal mask and a current field legal mask that works with the 68 Specials high shoulder mount. Left is my JT Thermal Spectra goggles. You can't see the plastic ear cups that I purchased after seeing an earshot drop a player. On the right is a JT Proteus. When I tried to play again they disallowed my first mask and all they had in the shop was an insanely expensive Proteus. I wanted to play so I bought it. After all that, I found that they only gassed the tanks for one game play. No liquid CO2 so I couldn't play anyway. The silver lining was that the Proteus lays right into the 68 Special for comfortable sighting in.

An introduction to my 68 Specials

My initial experience with the marker was not a good one, but getting an understanding and taking corrective action changed that experience from bad to great, making it my preferred marker of choice. I started paintball in about 1990 using a Splatmaster Rapide. This was at the request of a coworker who was invited to a between radio stations challenge and was requested to bring friends. I never played paintball before and somewhat reluctant, purchased a new marker and gear. The game went well and I was hooked. I eventually modded the marker with Gator and other parts and played regularly.

My first marker. A Splatmaster Rapide with Gator upgrades plus. My favorite tactic was to sprint the flag line on the whistle to flank the enemy before they positioned themselves, then come back and take them out with the 1x power Red Dot scope. The scope had poly-carbonate shields over the lenses but they have long been lost.

Most of the markers in the field were Nelspots and pumps and I only saw one SMG 60. I was on the receiving end. Hell yes they hurt. I was strafed across the chest at close range. Its owner had so much padding on that my ball had just bounced off without breaking. It was other wise a perfect shot. I learned an absolute and clear lesson then to shoot til they break.
A few months later my coworker showed me his new prize, a 68 Special. He pleaded for me to get one and we could mop the field. I looked at the price tag and said pass. He persisted and eventually I went to the shop and purchased the display as the markers were back-ordered with no clear future delivery date. I bought it on August 21st, 1991 for $369.00 plus tax.

This is what came in the box. The display 68 Special for $369.00 plus tax purchased on Aug. 21, 1991. Contained patch, manual, spare o-rings, 68 Special, 40 rnd hopper, 7 oz siphon tank with shoulder stock, squeegee, sling, Warranty card (not in picture), and a tank fill coupling with washer. I believe there was a coupon for paintballs that I never used.

I grew to hate this marker as the valve always leaked. I should have contacted Tippmann as I later found that their customer service was pretty good, but at the time they were backed up on orders, the field called and all markers seemed to have one or more issues of some kind. It was a good shooter and replaced my Rapide but I hated the intermittent leak issue. My coworker had to buy every new marker as it came out and quickly got cross with his wife. Three was his limit, no more markers til he sold some old ones. He offered me his 68 special with only months of use, for $150.00. I declined so he threw in all its accessories for the same price. I could use the two extra tanks and one was 20oz, plus I was looking to mod some barrels and so I accepted. I tested his marker in a game for function and loved it. After a thorough cleaning and oiling, I transferred my accessories and retired my marker. I have been using this marker since. I eventually replaced the valves in my original and it is now just as reliable. After seeing the Tippmann TILs, I suspect the problem was really the valve O-rings damaged by the store owner when examining the valve system on the display. It's my backup now. My construction job eventually ended and so did the funds for game play. I cleaned everything and packed it away.
A few years ago, I started playing again but it has been hard to find fields that properly fill tanks. Most were just pressurizing the tank. This gets most markers through a game but it doesn't get the 68 Special through chronograph. Most people now have never heard of a siphon tank or say oh no, you can't use that, it will damage the marker. My local field closed up due to the economy a few years back so I have been benched again. This gave me time to find out why and how my marker was so different from the others. Despite its fame or notoriety depending on who supplies the inconsistent data, Tippmann doesn't even seem to acknowledge that this marker ever existed. They sold all remaining supplies to PB Sports and no longer mention or support it. Any questions that I sent them went unanswered. I was excited with the SL return and then depressed with no mention of the 68 Special. I now found a field in a neighboring state and am once again getting ready to play. The following is supplied for those who have had the good fortune to come into possession of a 68 Special but can't find much about it. Most sites either omit critical information or have it wrong to begin with. Other than sales brochures, documentation is rare and data had to be extrapolated from related markers with known changes taken into consideration. Help with any missing information or error identification will be appreciated.

The Short History of the 68 Special

In 1986, Tippmanns SMG 60 Gen 1 had its strengths but even more faults. It sported an efficient 62 cal ball, available in semi-auto only or select fire(semi and full auto fire depending on trigger pull), tank feed, and 15 fast shot capability. Its faults were that it had no Safety switch, no velocity adjuster (Velocity was adjusted by changing out the mainspring, This was not even stated in the manual. Also most markers at this time had no field adjustment.), 15 round bursts on full auto that threw the expensive clips into the bushes, a system that would spaz on liquid CO2 if fired at downward angles, and a frail gas line on the outside of the receiver. Tippmann then made the SMG 60 Gen 2, the gas line was moved inside, and a set screw behind the trigger could disable the full auto mode, but it still had no mechanical safety (The instructed safe position was lowering the bolt into closed position, striking the bolt handle could still fire the marker.), the liquid CO2 issues remained, had no field velocity adjustment and the 62 caliber ball was becoming increasingly harder to find. In 1987, Tippmanns response was the SMG 68. This is the first of the Wet CO2 markers. It used a siphon tank to intentionally draw and use the liquid CO2 to an advantage (I believe that the valve is the same as in the SMG 60 Gen 2 but the increased force from the previously undesired CO2 liquid feed could fire a 68 cal ball very well. Serendipity?), it still had no mechanical safety, but it was stock SEMI AUTO ONLY (full auto SMGs were being banned at some fields. Some users quickly found that installing a SMG 60 Gen 2 trigger gave this marker full auto capability, the threaded set screw hole for full auto disable was still in the receiver frame and could be used). In 1988, Tippmann released the SL 68. An economical pump that again used "Dry System" CO2 and a 40 round gravity fed hopper. In 1989, The SL 68 was doing well but for the semiautomatics, the velocity control and the lost clips were still issues. Competitor markers began sporting semi auto fire but with simpler gravity fed hoppers. In 1990, Tippmans final Solution was the 68-Special. It still had no mechanical safety, it did have a velocity adjustment screw, it had the siphon tank from the SMG 68 and a 40 round gravity fed hopper (The hopper neck was undersized and adapters had to be used for installing aftermarket hoppers, The necks were also prone to breakage if over tightened or if forced to open wider.). Tippmann then initiated a program to perform a non-reversible upgrade on sent in SMG markers for about a $100.00 fee. Later, the roll pin under the valve was omitted, the valve was milled, and a C spacer was installed to ease valve floating for more consistent velocities. Shortly after that the side notch in the bolt tube gave the marker its first mechanical safety. Now we are at the final version of the 68-Special. The evolved marker designed with on the fly improvements and corrections. This marker was built using the existing factory parts of its various SMG predecessors. It was a veritable paintball Prometheus, taking the best of all its ancestors. Sadly this was also the last model of this innovative series. The 68-Special had two main variations. The release model, which had a roll pin valve retainer under the valve, a power tube with a steel rod insert, and no mechanical safety. The final version which had the grooved valve with a C shaped valve retainer/spacer, a one piece power tube with three holes, and the mechanical safety. Because of the upgrade program and factory service upgrades, 68-Special markers may have on the nameplate SMG 60, SMG 68, or 68-SPECIAL. They may also have the later power tube, valve spacer/retainer, and the safety notch on earlier models. The distinguishing factor for a 68-Special will be the hopper clamp on the right front of the receiver.

WET CO2 Systems (volume) VS DRY CO2 Systems (pressure)

Take everything you were told about paintball markers and trash it. It most likely does not apply to the 68-Special. Other than the early Z series and the Mega Z made by Montneel Designs, no other markers were designed to cycle liquid CO2 in them. It looks to me that this was an accidental system discovered in the SMG 60 liquid CO2 malfunctions. The Montneel markers were initially based on the 68-Special with focus on an improved valve design and on upgradability. These, the SMG 68s and the 68-Specials are referred to as "WET CO2" systems and they actually use a different physics than "DRY CO2" system markers.

Dry markers use the CO2 in gas form to fill a firing chamber. A pressure regulator limits the gas entering the chamber to a fixed pressure that on sudden opening, the escaping gas pushes the ball to its velocity. As the ball travels down the barrel, the pressure drops as the gas was already expanded in the expansion and firing chambers prior to release. This is why barrel length has limited effectiveness of about 14 inches. The upside is that you can reduce velocity and save gas. The downside is temperature sensitivity. The system cools on consecutive firing. On rapid fire, the pressure can drop to less than the regulated pressure and ball velocity suffers. Also tipping the marker to allow liquid CO2 to enter the system can cause dangerous pressures and damage the marker as well as exceed safe shooting velocities.

Wet markers run liquid CO2 directly to the valve with NO regulator and NO expansion chamber. The valve size and the force of the hammer strike pushes out a FIXED volume of CO2 liquid that expands rapidly outside the valve and in the power tube. The set screw on the side of the power tube uses turbulence to cause back pressure, this higher pressure slows the conversion of liquid to gas. After that, the liquid to gas conversion pushes the ball with increasing pressure unlike the dry system that releases all pressure at once. With a wet system the tighter the ball seal and the longer the barrel, the higher the exit speed. Longer barrels DO get higher velocities on wet systems. The limit is when the forward bolt pulls back far enough to release barrel pressure. Keep in mind that you're still limited by field velocities. 270 is 270 whether pushed violently at once (dry) or through rapid acceleration (wet). The good side is that with a wet system, you are at maximum velocity. If Gas CO2 should enter the system then the velocity will lower and not get dangerous like liquid CO2 in dry systems. There is substantial confusion about this because of velocity bursts of the SMG 60s when tipped forward and liquid enters the valve. (There was no anti-siphon device in Tippmann tanks, in fact Tippmann still does not recommend them.) SMG 60s were NOT siphon markers, They were designed as dry systems with no regulators and the tank itself being the expansion chamber. More confusion comes from POST SMG parts lists that list Siphon Tanks as an option. I have found no manuals exclusively for the SMG 68 and all evidence shows that a SMG 60 manual was sent with new SMG 68 markers. The siphon option was only intended for the 68 Cal and standard tanks for the 62 Cal but that fact was never clarified. This has resulted in all types of absurd comments on 68 Special velocities and quirks, all rumors. Rumors repeated so often that they are now regularly confused with fact. The wet system is SAFER than dry systems. The only downside is that the amount of CO2 used in shooting is much higher.

The simple fact to remember is that wet systems work on volume and dry systems work on pressure. Liquid cannot be compressed, a chamber of a fixed size holds liquid at a fixed volume. If some of the liquid turns to gas, then the volume is actually reduced. This is not true with gas, where a chamber of a fixed size can hold different volumes of gas at different pressures and are greatly affected by temperature changes. If the marker is chronographed after the system is properly wetted, three rapid shots with barrel up, then the maximum velocity is shown. Any gas entering the system or forming in the system on a hot day does not increase the velocity. Wet systems use the rate of expansion, liquid to gas, not the expanded gas pressure to push the ball. The small valve area can only release a small quantity. The more expanded gas in the valve, the less liquid there is, the less liquid there is, the less there is to convert to gas on release and therefore the less there is to push the ball with resulting in lowered velocity. All expanded gas in the valve critically lowers velocity and does not push the hammer sufficiently to catch. The wet system IS safer. Using the liquid to gas conversion is also why a wet system can be effectively used in cold snow covered areas where ""Dry" CO2 pressure systems fail to perform well. It also allows rapid-fire WITHOUT a significant drop in velocity. A real kickbutt feature before the use of HP air.

If you have ever seen a 68-Special in action. You probably saw the result of just gas in a wet system when the liquid runs out, there is not enough force to blow back the hammer to catch on the sear and the marker machine-guns chopping up balls with a loud BBBBBBBBBRRRRRRRAAP. Back then, we called those Tippmann gun farts. The barrel then required cleaning and a rush was certain. If you didn't have buddies or a back up piece, you were usually screwed. The main reason I went to a 20 oz tank. Tip: If your 68 Special starts to Machine-gun, tip it upside down and change the tank as fast as you can. Turning it over stops the ball chop and clears some debris from the barrel during the machine-gun. After tank change, right the marker, and Re-cock. It will fire some unbroken balls. The accuracy will not be there but you can take out the rushers giving you time to safely sqeegee your barrel. The MYTH about tipping the 68 Special marker certain ways and getting higher velocity has been one of the most aggravating issues that I've had to deal with in the field, even in the 90s..

On a side Note

Can you convert the 68 Special to HP air? Sorry, no. The valve capacity is too small and the feed line from the tank is a spring encased 1/16" plastic tube. It is too small to allow adequate air flow. It will overheat and/or rupture before adequate pressure can be reached for the valve size during rapid-fire. The valve seats are also not designed for the required HP pressures. On impact the valve is designed to release liquid CO2 on both sides. The valve is free-floating so roughly an equal release is on both sides. One side drives the ball and the other drives the hammer back to catch the sear. Besides not having any expansion chamber or internal regulator, The hammer itself weighs 275 grams or 9.7 ounces. That's more then a half pound cycling on each shot. The gas would have to overcome the inertia of the hammer as well as being able to reset the mainspring, furthermore it would have to propel the ball to proper velocity. Without a complete redesign of the whole system, satisfactory HP air is not possible. Most of the blown lines I have read about were during a test cycling of CO2 gas or compressed air and not the proper liquid CO2 as required.

On my future posts I will be supplying some tear down pictures for those repairing or restoring their markers. Debunking 68 Special Myths. Tippmann siphon tank innards and hopefully how to build them. I would also like to review velocity issues and supply some videos. If all goes well I will eventually supply details on a major mod on my third 68 special. [TOP SECRET ]

SML

Blogger.com user StrayBlackCatsMeow

Address http://68-special.blogspot.com/
Blog "The 68-Special from Tippmann Pneumatics Inc"
Blog Reference page number 01
Title - The Serendipitous Paintball Marker
Revised - 05/24/2017