The VM-68 FAQ to-end-all-FAQs

v5.2 Last Updated 1/10/96
Written by Nick 'Jinxed' Brassard TIP #173
VM Faq up to v2.0 written by Doug Seman TIP #11
HTML version by Bill Mills TIP #86

This Document is Public-Domain, and can be distributed freely. I made this FAQ for those who love paintball and their VMs. I do not care if its copied, and hacked up, but I would appreciate it if my name and Doug's was kept in it somewhere. Thanks


1. GENERAL 2. Maintenance/Trouble Shooting.
    1. GENERAL

    The purpose of this FAQ is for all those PMI3/VM68/VM-Magnum/ VM-EXC users, who are sick of seeing all those giant AUTOMAG/ AUTOOCKER/PROAM mega-bandwidth FAQS. This IS the paintball FAQ to-end-all-FAQS. The PMI3/VM68/VM-Magnum/VM-EXC is, for the most part, the same paintball gun. The PMI3 is an early version of the VM-68, and all parts are compatible (except early PMI3's have NON-reversible hammers, Reversible bolts, and liquid UNfriendly cup-seals). The VM-Magnum is the same as the VM-68, plus a nice "Bull" barrel, dual-bottle adapter, field strip screws, black (or "REAL TREE") anodization, and is truly ambidextrous. The VM-exc is also the same as the VM-68, except with a built-in expansion chamber, bottom line, sight-rail, and is also ambidextrous. The typical price of VM68 is $190-230, VM-magnum is $230-290, and VM-exc is $240-290. Throughout this FAQ will refer to them simply as the 'VM', except when special differences are noted.
    The VM-68 is a .68 calibre, true blow-back semi, firing from an open bolt. The VM is based on a design that Benjamin/Sheridan designed about 20 years ago (for pellet guns). In many ways, the VM has the same basic internal structure as the PGP, PMI-x, KP-x, and Sheridan BB guns. Other famous guns that are derivatives of the Sheridan design, are: BudOrr Sniper/Cocker, Promasters, F1/2s, Sterlings, and Spyders.
    NOTE: The Sheridan EQUALIZER has compatible barrels and feed blocks with the VM, but otherwise they are TOTALLY DIFFERENT guns (more similar to a 'mag then a Sheridan).

    While Sheriden has been around for a very long time, but has recently been bought by CrossMan airguns. (rather like Daisy buying BrassEagle). Also, up until 1992, all Sheriden paintball guns were distributed by Pursuit Marketing Inc. (hence: PMI-x). This is only important because it means all the phone numbers and addresses may be different then when you originally bought the marker. The current address and phone number is:


    Unlike most others semi's, the VM requires no general maintenance. This is often the main reason why people choose the VM over the semi's available. However, its important to keep the gun clean, and well lubricated.

    In my years, I have talked to 1000 people about their VMs. Each one of them has their own separate idea on proper VM lubrication. 2-E of the AllAmerican's says that Sesame seed oil for the internal hoses (if any), keeps any liquid co2 from clogging up the system. The VM manual suggests vegetable oil, or vaseline, which I don't suggest. Some local VM teams use a thin layer of AXLE grease, mixed with vegetable oil. However, I have found that ordinary gun lubricant, like GOLD-CUP or 3in1, works plenty fine. For the most part, ANY lubricant will work fine, just as long as it doesn't contain 2 things: 1. Anything petroleum based, 2. Thicken when it gets colder. This means DON'T put WD-40 in your VM. All petroleum based lubricants EAT o-rings. While I realize VMs have far fewer O-rings then many other GUNS. When your CUP-SEAL goes in the middle of a battle, you'll wish you didn't use that WD-40. Also, LITHIUM grease, and other automotive lubricants tend to thicken in cold weather, causing cycling problems (see below). Plenty of fine paintball-only lubricants are available, though, are expensive.

    You would be surprised the number of newbies I find who cannot properly adjust the velocity of a VM. Dont feel bad, though. The VM is by far the most complicated paintball gun to change the velocity on. (even more then changing springs). There are 2 methods of adjusting the velocity on a stock VM: the bolt, and the valve. (plus a few 'trick' methods further in the FAQ).


    If your VM leaks for any reason, 99% of the time, it is the CUP- SEAL (other wise its a valve o-ring, or bottle o-ring). The cup-seal is a small cup-shaped seal, attached to a pole and a spring, that sits inside the valve. In VM's, its the ONLY thing that holds the Co2 inside the gun. All VMs made after May, 1992, have the 'new' cup seal. Its the same as the old one, except, its much shorter, and friendlier to liquid. Either way, any of them can go bad. If you ever screw in your bottle, and co2 flies out of your gun like crazy (turning the VM into an aluminum ICE CUBE), or even a small leak coming out of your barrel, means the CUP-SEAL is going bad. If a new cup-seal is unavailable, their is 2 temporary solutions. First, disassemble the gun completely, and cover the cup seal with a THICK lubricant, like WHITE LITHIUM or vaseline (temporary). Re-assemble, and pressurize. If this doesn't work, disassemble the VM again, and SQUEEZE the VALVE and CUP-SEAL tightly, while turning, to make a better 'seat' for the cup-seal. Re-assemble, and pressurize. If this doesn't work, you must get a new one. If you had the older style, get the new style, they last longer.
    In desperate emergencies, a cup-seal from some other SHeridan based gun (Sniper/Cocker/Pmi-x/etc) may or may not work. I have had mixed results. Borrowing someone's spare cup-seal is alot better then going home WITHOUT war-stories....

    d. VM CYCLING.
    It seems that everyone has a problem with their VM cycling at one time or another (the 'full' auto effect). Below is a step-by-step guide to solving the cycling problem.

    vi. MISCELLANEOUS TROUBLESHOOTING. A. ** Screws **. Keep in mind that the body of a VM is made from soft aluminum and magnesium. It is very to strip the threads for a screw. If the threads become stripped, they needs to be re- drilled and tapped to a larger drill size. Plus, it is also easy to strip the faces of the allen-bolts from over-tightening (which means you can't get the screw out). If this happens, try using a bolt-removal tool. If this fails, the bolt needs to be drilled out, as well as the hole. Then re-tapped to a larger size. This is a good reason to buy the field-strip kit for the VM. It is much harder to strip the screws with it. B. ** Bolt-Stick. Bolt-stick is a very rare occurrence of a bolt 'stopping' within mid-cycle. This often occurs with aftermarket parts, and can come from a variety of places. Often the bolt orings will become worn and cracked (especially stock), and can sometimes create enough friction to stop the bolt. Sometimes paintshells can get behind the bolt, and jam it (especially delrin). Some after-market hammers cause this. Probably becuase the sear is getting caught when sliding across the hammer (or maybe its the sear release pin)... still studying this phenom. C. ** Double-Feeding **. Double feeding can only mean one thing. Your "Magic Fingers" have gone bad. The Magic Fingers is my name for the rubber ball-detent found in the feed block. They can become damaged for a variety of reasons (including aftermarket bolts). Fortunately, they are cheap and you can get them at most pro-shops. D. ** Excessive Ball Breakage **. The VM rarely breaks paint, so if ball breakage becomes excessive, something might be broke. First: The VM might be double-feeding (see above). Second: You might be missing a bolt o-ring. Missing a bolt o-ring would cause excessive co2 to enter the feed elbow when firing, slowing the feed rate, pinching balls. Third: the stock brass barrels bends easily if dropped. Plus, check inside the barrel for excessive scratches. See if you can easily BLOW a paintball through the barrel with your lungs. Forth: Perhaps you are using bad paint, or even firing the VM faster then it can feed (unlikely).

    3. ** UPGRADES **

    a. GOING 'STOCK'

    I just want to make this note about a stock VM. A stock VM is a fine gun. The only reason 'mag owners, and 'cocker owners make fun of it is that they paid $1000+ for their guns, and are jealous that some newbies $200 gun is just as good!

    b. BARRELS.

    c. C/A

    i. SETUPS.

    For some odd reason, ALL SHERIDEN guns take in co2 from the front off the gun. (Piranhas, VM-EXC, and VM-Magnums don't count since they are custom versions of front-co2 sheridens). During the 12gram days, this was no problem. Unfortunately, the front-bottle system on the VM severely limits it. In the stock form, only a 7-10oz can be used.

    Fortunately, there are many options for barrel re-placement. The most common is BOTTOM-LINES. Plus there is also BACK-BOTTLE setups. Both these have versions that allow for dual-bottle setups. Many VMs experience problems with screws loosening with back-bottles, you may need to use LOC-TOURNAMENT or LOC-TITE on the field strip screws. Plus, the bottle can be run on remote, or, the bottle can be retained in the frontal position, but at a 90 degree, or 45 degree angle. Still yet are intruder systems, which put the bottle on a bottom line, but on a frontal grip.

    The VM has more c/a setup options that ANY OTHER GUN. This allows the VM some freedom, as well as some distinct looks. All these allow the VM to use a co2 bottle of 3-40oz. Most people opt for the bottom line, with an expansion chamber (like the Black-Rain). Bottle re-placement kits are usually inexpensive, around $30-50. You can also use on/off valves, filters, and quick disconnects. These little brass pieces can run from $5-$30. IMO filters are a waste of money, and have NEVER HEARD of a VM going down because of dirty CO2.


    The most common complaint of the VM is its co2 efficiency. A stock VM, with 7oz usually gets 100-220 shots from a 7oz. The large range is shots is due to weather, temp, and condition of the VM. This is hardly enough for a game, let alone for a whole day. Different setup can be used to allow for bigger or multiple bottles, but, special co2 devices can be used to allow for 350-450 shots from a 7oz. These devices are expansion chambers, regulators and/or remotes.

    iii. SIPHON.

    The one cure-all for velocity problems, cycling problems, cold weather problems, and consistent velocity problems is to use a SIPHON tank. Siphon tanks allow the VM to drink straight LIQUID co2. This allows for a GREATER operating pressure. Most other blow- back semis use SIPHON tanks (ICON Z1/2, PROAM/LIte). The only drawback is efficiency. With a siphon, expect only 100-150 shots from a 7oz. This means a 20/32/40oz is a MUST. Although, if the VALVE it drilled out bigger, you'll get 130-175 shots from the 7oz. VMs CANNOT run on a SIPHON and EXPANSION chamber at the same time, as they are contradictions (people really ask me that). Plus, the VM will blow giant VAPOR clouds which impress the newbies (and give away your position). Make sure your VM was made after MAY 1992, as it may have the 'old' cup-seal. Siphon tanks are the same as regular PV tanks, except have a special $10-15 SIPHON VALVE. (TIPPMAN or TPI makes the best). It should be noted that since running on a SIPHON means your velocity rises when rapid firing, you should crono this way, to get an accurate fps reading. NOTE: Most tournaments require you to chrono this way if you use SIPHON, which is a GOOD thing becuase its nearly IMPOSSIBLE to get a HOT shot if you chrono on 'liquid'.


    The VM can run on NITROGEN/HPA just like the 'mag. Many quality kits (ie expensive) will allow the VM to get nearly 1000 shots between fills. Running on NITROGEN has same benefits that SIPHON tanks provide like stable velocity, and all-weather performance (without the cloud). Most NITRO kits run from about $200 (low pressure), to about $500 (HIgh pressure). I should point out that NITROGEN is quickly becoming the choice of tournament players. Mostly becuase 'Cockers and 'Mags are sensitive to liquid co2 (unlike the VM). So if you are worried about the availibility of nitrogen in the future, I wouldnt worry. I predict all tournaments, and most fields will have NITROGEN capabilities in the near future.

    The VM is an UNUSUAL gun, in that it can run on an EXPANSION CHAMBER and NITROGEN like a 'mag or 'cocker, with great results. Plus also run on SIPHON like a ICON Z1/2 or PROAM/LITE also with good results. This ability makes the VM an EXCEPTIONAL paintball GUN.

    d. ** INTERNALS **


    i. Various Custom Setups

    Often, I get E-MAIL from people asking how they should customize their VM, and I always tell them..."Any way you want". Below is some example of Custom 'HOT-ROD' VM configurations from different posters:

    ii. Should I buy a VM?

    Before buying -ANY- paintball gun. Ask yourself, how much do you plan on playing? Also, ask, do you want to ability to upgrade in the future? For the NEWBIE, there are basically 5 choices of ENTRY level SEMIs: 1 Stingray ($100), 2: VM ($200), 3: PRO-LITE ($250) 4: F1/2 ($250). 5: SPYDER ($200). If you plan to play a couple times a year, with friends, perhaps the STINGRAY is best, but otherwise, I would recommend the VM. Its cheaper then the PRO-LITE and F2, and can be UPGRADED much further then the SPYDER, and is superior in many ways to all 4 guns. BEFORE you make the choice, go to your local field, and ask to TRY some guns out. Different people have different opinions.

    iii. general

    Information in this FAQ came from a variety of places. Much came from my 4 year experience with a VM. ALso Doug Seman, author of the original FAQ, David Bowden, Brian Quan, Jay Tu, and whatever stuff I could swipe from WARPIG. The VM can range from the ENTRY LEVEL marker, to the TOURNAMENT level mega-marker. This is the main reason why there are more VMs then any other paintball gun. Sure, the VM has its idiosyncrasies, and may not be the gun for some, but is a fine gun, made from one of the oldest paintball/bb gun companies. No matter how you look at it, the VM is a piece of QUALITY and HISTORY.


    In the last 9 years of playing paintball, I have used nearly every paintball gun ever made. Out of all of these, the VM remains my favorite. I still have the first one I bought 4 years ago (though it has been hacked up). My teamates think I am crazy, which I am. Plus, being my teams TECH-man/Air-Smith (guy who gets to fix all the guns), I have a rather good idea about a VM also. I would love any suggestions or ideas to be added/deleted.

    JINXED! Master of the Pan Flute!!

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