Those of you who have frequented this site will see that there have been some huge changes in this section. I was never really satisfied with the troubleshooting section I had before. It was OK, but really not complete and poorly organized. I set myself to the task of putting together solutions for every Autococker problem I could think of. The result was a series of three articles that appeared in Paintball Games International. The first was an article on how to time the Autococker. It only covered timing and did not address any problems that could complicate timing. The second covered every Autococker leak I could think of. The third was the wastebasket. It covered every other problem I could come up with, including all of the things that can make timing a nightmare. These appeared in PGI during 1999 and 2000. I've decided to put them in here with some links to make navagation easier. I think you'll find this to be the single most complete Autococker troubleshooting text around.


Timing the Autococker Coping with Autococker Leaks Every Other Autococker Problem You Coud Ever Hate to Have

4 Easy Steps to a Properly Timed Autococker

Timing an Autococker is seen by many as being a black art, known and practiced by only a select few who have the "touch" to get an Autococker running properly. In fact, timing an Autococker is pretty simple, but there are a lot of little things to pay attention to when you're doing it to get it right. It's most often these little details and a fundamental misunderstanding as to how the Autococker works that trips people up.

I'll start by saying that the most effective way to make sure that your Autococker works well for the long term is to NOT fiddle around with it. If you're Autococker is in good time and is working properly, you should stop reading this article now. This guide is only for those who's 'guns are hopelessly out of time, and who don't have an experienced Autococker tech to help them out. I promise you that if you're 'gun is working now and you try to use this article to make it "even better," it will almost certainly come out worse. It is not a guide on how to do a trigger-job. It is not a comprehensive trouble-shooting guide (I'll be writing one later). This is a very basic guide to tell you how to get an Autococker (or Minicocker) properly timed. The first time you try it, it probably won't work very well. But with time and practice you should eventually become quite proficient at timing Autocockers using these basic principals as your guide.

Before I begin, you should know that I'm making some assumptions about the 'gun that is being timed. I'm assuming that the autococking system regulator (on the front of the 'gun) is properly set and is feeding sufficient pressure to the autococking system to cycle the 'gun. I'm assuming that the trigger and sear are sprung properly such that there is enough tension to close the 4-way valve when the trigger is released, and enough tension to keep the sear-lug from slipping over the sear. I'm assuming that your sear lug and sear are not worn out to the point where they will no longer catch. If any of these things are pre-existing problems, you will not be able to time your Autococker.

Step 1: Set back block position

The block is the part at the back of the 'gun that is screwed onto the pump rod, connecting it to the ram. The bolt and cocking rod go through the block and are drawn back by it when the 'gun is cycled. Positioning the block properly is probably the single most neglected setting on Autocockers. The block position is very important to ensure that there is enough backward movement of the block to cock the 'gun and allow another paintball to drop into the breech.

Having the block screwed in too far can lead to several problems. Obviously if it's in way too far, it could not move back far enough to cock the 'gun or allow a paintball to drop into the breech. In less extreme cases, the ram has to push all the way to the back of it's stroke (where it is weakest) to draw the hammer back far enough to catch the sear. In this case, any reduction in pressure through the autococking system will lead to the block not being pushed back far enough to cock the 'gun or completely feed the next paintball. During slow-fire, this isn't a problem. But during rapid fire, when the regulator may not be fast enough to provide a steady flow of pressure it leads to stumbling, double-firing, and chopped paintballs.

You want to screw on the block such that, when the ram is all the way forward, the block just touches the back of the body. This accomplishes a few things. First, it ensures that the block can definately be pushed back far enough to cock the 'gun and that ram is in the middle of it's stroke (where it's strongest) when the hammer has been drawn back far enough to catch the sear. Second, it ensures that the block will definately be able to draw the bolt back far enough to allow a paintball to drop into the breech. Finally, with some work, you can actually position the block such that the block comes right up to the body, but doesn't actually meet it. This eliminates much of the clacking sound characteristic of an Autococker cycling.

Block positioning

Step 2: Set cocking rod length

The cocking rod is the rod that goes through the block and velocity adjuster below the bolt and screws into the back of the hammer in the lower half of the 'gun body. It has a knob at it's end and must be removed to set the velocity on most Autocockers. Oddly, this is also a commonly neglected aspect of timing the Autococker. Setting the rod's length properly is absolutely crucial to ensuring that the bolt can move back far enough to allow paint to feed, and to ensuring that the hammer is drawn back far enough to catch the sear.

Rod length problems manifest in two ways. If the rod is set too short, the block's backward travel will be limited such that paint will chop during rapid fire, or not feed at all in extreme cases. If the rod is set too long, you run into the same problem you have when the block is screwed in too far; during rapid fire, the 'gun will sometimes stumble and double fire (the hammer doesn't catch the sear and stay back).

The rod's length is set by it's knob, which screws onto the rod. To lengthen the rod, unscrew the knob from the rod. To shorten it, screw the knob on further. The knob is locked in place with loc-tite on older knobs, and with a small allen screw through the back of the knob on newer stock and aftermarket rods. I'll admit that these can be a total pain in the ass. Shocktech has a new rod that makes life much easier. I highly recommend it.

You want to set the rod's length such that, when the hammer catches the sear, the bolt has completely cleared the breech. This is most easily done with the 'gun degassed. When you pull the block back it will catch the rod and draw it back, pulling the hammer with it. When the hammer catches the sear, you'll hear a light click and the rod won't try to pull the block forward anymore. You can pull the block back further, but spring tension will return it to that point. This point, with the block as far back as it will rest with the 'gun cocked (ie. the hammer caught), is where you want the bolt to be completely clear of the breech. Look into the feed tube and see where the tip of the bolt is positioned. You want it to be completely clear of the breech, but not drawn too far back beyond the back of the breech. Ideally, you want the bolt to just clear the breech when the hammer catches. This ensures that every time the 'gun cocks, the bolt is drawn back far enough to feed another paintball.

Correct cocking rod setting

If the bolt is partially occluding the breech, it may still be drawn back far enough to clear the breech, but any decrease in cocking pressure through the reg could result in a small reduction in the distance the block is drawn back. If this is the case, it could still be drawn back far enough to cock the 'gun, but not far enough for the bolt to clear the breech, resulting in incomplete feeding and possibly a chopped ball. Lengthen the rod by unscrewing the knob until the bolt is completely clear of the breech with the 'gun cocked.

Incorrect cocking rod length (too short)

If the rod is too long, the ram may have to go all the way to the back of it's throw to cock the 'gun. This can lead to the same problems as with the block screwed on too far. If you see the bolt going more than 2 mm past the breech, shorten the rod by screwing the knob further on.

I should note here that others do this differently. They are happy if the bolt clears the breech completely with the 'gun gassed up and the trigger pulled. This is fine as well if you absolutely know that your low pressure reg is perfectly reliable in recharging quickly or you have the pressure turned up higher than necessary (an extra 1/2 turn or more on an adjustable reg).

After adjusting the rod, always remember to lock it back in place with the locking screw or with loc-tite.

Step 3: Set sear-lug length (firing point)

The third step is setting the point where the 'gun fires in the trigger-pull. This is set by setting the sear-lug length. The sear lug is a screw that goes through the hammer, and is the part of the hammer that catches the sear in the grip frame when the 'gun is cocked. If you have a stock Autococker, you have to remove the grip frame to adjust the sear-lug. If you have a 'cocker with an external sear access hole, you can drop a wrench through the top of the'gun to adjust the sear lug without having to remove the frame.

Lug adjustment

When setting the length of the sear-lug, there are a couple of things to keep in mind. First, you want to make sure that there is enough lug catching the sear for the two to hold reliably with each fire of the 'gun. Setting the lug too short (a common mistake made by people trying to shorten their trigger pulls) can allow the sear-lug to slip over the sear once the parts get worn in some so the 'gun won't stay cocked on every shot. Second, you want to make sure that the 'gun fires early enough in the pull for you to set the cocking point (step 4) past it.

Screwing the lug back into the hammer such that less of it protrudes below the hammer moves the firing point forward in the pull (makes it fire earlier). Screwing the lug further out of the hammer so more of it sticks out below the hammer moves the firing point back in the trigger pull (makes it fire later).

In my time with the Autococker, I've found that the lug has to be set to allow the 'gun to fire at least half-way through the trigger pull for reliable operation. Though you can set it to fire earlier than that, I've found that eventually sear and lug-wear lead to the hammer slipping over the sear. A good marker I use to set the firing point is the alignment of the holes in the trigger-plate and grip frame that the timing rod goes through. The trigger is about half-way back when the hole in the trigger-plate is centered in the hole in the grip frame. I typically set the 'gun to fire at that point. You can set it to fire further back in the trigger-pull, but I haven't found any real tangible benefit from that.

Centered holes

Step 4: Set the timing rod length (cocking point)

The final step to bringing your Autococker into proper time is to set the point in the trigger-pull where the autococking system is triggered to cock the 'gun. This is set by adjusting the length of the timing rod. This is the only step in timing the Autococker where the 'gun actually needs to be gassed up.

The timing rod is the bent rod on the right side of the 'gun that attaches to the 4-way valve at it's front and bends to go through the trigger frame and plate at its back. You'll note a small collar that the front end of the rod goes into. This collar couples the rod to the 4-way. There are two screws in this collar. The front screw attaches the collar to the 4-way. DO NOT REMOVE OR LOOSEN THIS SCREW! The back screw is the one that holds the rod in place. This is the screw that you have to loosen to adjust rod length. If you have a stock timing rod, the rod simply slides into the collar. It can be adjusted by loosening the back screw and sliding the rod in or out as needed. If you have a threaded timing rod, the rod screws into the collar, requiring you to rotate the collar around the rod to shorten or lengthen the rod after loosening the screw. Shortening the timing rod moves the cocking point of the trigger pull forward. Lengthening the rod moves the point where the 'gun cocks back in the pull.

Setting the timing rod

Since the way an Autococker works is to fire with the first part of the trigger pull, and to cock with the second part, obviously you want to set the point in the trigger pull where the 'gun cycles behind where it releases the hammer and fires the 'gun. To minimize blow-back (gas blown up the feed-tube), you want to set the trigger-up such that when the 'gun fires the bolt is still being held firmly forward, and only after that does it cock. I check this by slowly pulling the trigger back until it fires. When it fires, I watch the block. If the block starts to move back before, or jumps back when the 'gun fires, I lengthen the rod slightly and try it again. I repeat this procedure until when the 'gun fires, the block stays firmly forward, and doesn't start to move back until I slide the trigger further back. This ensures that the 'gun has fired before it starts to cock, and reduces blow-back to a minimum.

A too-long timing rod can result in several problems. If the rod is extremely long, the block will always stay forward no matter how far you pull the trigger since it can't pull the 4-way piston back far enough. In less extreme cases the 'gun will cock close to the back of the trigger pull and will start to move forward on trigger-release before the sear has come forward far enough for the sear to catch the lug. In this case, the block will cycle without the 'gun firing and the cocking rod slips forward on each return of the block. In the least extreme cases, the sear-lug will only sometimes slip over the sear, resulting in occasional double fires followed by dropped shots.

A too-short timing rod has several consequences as well. If the rod is far too short, the block will always stay back, even with the trigger completely released. In less extreme cases, the block will begin to cycle before the sear can release the hammer and the 'gun will cycle without firing. It differs from a the too-long rod instance in that the 'gun stays cocked with the cocking rod staying back in the cocked position between cycles rather than returning all the way forward. In the least severe cases, the 'gun will appear to function normally, but excessive blow-back will result in poor velocity consistency and occasional chopped balls during rapid fire and when your hopper runs low on paint.

Addendum for 2000 and later Autocockers, 1999 and later STOs, and ANS Autococker users: In all STOs since 1999, Autocockers after model year 2000 and all ANS Autocockers, the trigger plates have been modified to have a hole for the timing rod rather than a slot. The result of this is that you can not time in that ideal gap between firing and cycling that I describe above. The reason for this is that there is no longer a lag between forward movement of the trigger (and thus raising the sear) and switching the 4-way valve back. As a result, since you time the sear to drop first then switch the 4-way, when you release the trigger the events reverse and the 4-way switches back before the sear can ride up high enough to catch the lug.

Because of this change caused by the new trigger plates, you have to set the cocking point of the trigger pull very close to, if not directly coinciding with the point where the sear is released and the paintgun fires. The advantage of this is that your trigger pull is made much shorter and the trigger is much harder to short-stroke. There is some delay in the buildup of pressure as the 4-way switches allowing this to work without massive blowback. None the less, you should expect more blowback and the need to replace your sear/lug more frequently since this new system slips out of time with much less wear.

By the way, if you have one of these new plates and do not like this new arrangement, you can get old-style slotted plates for both pre-1998 and post-1998 trigger frames. Both RAGE Sports and P&P carry them.

That's it! Assuming that nothing is wrong with the rest of the 'gun, these four steps should get your 'gun back in time and working properly. Since I gave a lot of detail above, I'll just summarize the four steps one more time.

  1. Set the block such that it just touches the back of the 'gun body with the ram all the way forward.
  2. Set the cocking rod length such that the bolt completely clears the breech when the sear catches.
  3. Set the sear lug such that the 'gun fires at or past the half-way point of the trigger pull.
  4. If you have a slotted trigger plate, set the timing rod such that the block stays firmly forward when the 'gun fires, and such that the 'gun cocks after it fires. If you have a new Autococker with the slotless plate, set the cocking point right at the point where the paintgun fires.

Coping With Autococker Leaks

The leaky paintgun has to be one of the most frustrating things in the sport. They can be an irritating hiss that nags you through a game, or a full-blown gale that forces you to sit out a game tearing down your paintgun or air system to replace a small seal. Let’s face it, though: most leaks are pretty easy to fix. At a hose joint, a little teflon tape or loc-tite seals things up nicely. A tank that leaks when screwed in usually calls for a new tank O-ring. Rarely, a barrel leak requires a new cup seal. With most paintguns, these are obvious and easy fixes.

The Autococker, though, is an entirely different beast. Due to it’s more complex pneumatic design, large number of parts, and comparatively easy access to operating settings, the Autococker offers a much wider variety of leaks and causes than most other paintguns on the market. While with most paintguns the cause of a leak is nothing more than a bad seal, the Autococker as often has some setting or adjustment at the root of the problem. As a result, inexperienced players give up in frustration. Some people just learn to live with air leaks. Others switch ’guns entirely just to escape a persistent leak. You don’t have to resort to either of these options if you know just a little bit about how the Autococker works. My goal here is to tell you how to diagnose and fix the most common (and some of the very rare) leaks that can present in the Autococker. I’ve broken this down into sections corresponding to the source of the leak — barrel leaks, 3-way valve leaks, and miscellaneous other leaks.

Barrel Leaks

  • Cock the paintgun before gassing up: Probably the most common cause of barrel leaks is nothing more than the hammer resting against the valve and holding it open when the paintgun is first gassed up. This isn’t really a problem, just the new Autococker-user’s misunderstanding. If your Autococker starts to vent air down the barrel when you first gas it up, it’s probably because you haven’t cocked the hammer back first. Just make sure to pull back the cocking rod or the back block until the hammer locks back before attaching or turning on your air source.

  • Dry cup seal: If you notice a slow leak down your barrel, you may just have a dry cup seal. Put a few drops of oil in your ASA before gassing the ’gun up and cycle the oil through the paintgun. This will often help seal up very minor leaks. Tip: take your barrel off or turn your bolt upside-down before doing this to avoid spraying the inside of your barrel with oil.

  • Blown/damaged cup-seal: If a little oil doesn’t clear up your leak, or you have a more vigorous leak, it may be that the cup seal in your valve is damaged or blown out completely. If this is the case, you’ll need to buy a new cup seal (remember to buy the right one if you have an aftermarket valve!) and replace it. Replacing the cup seal is rather involved and requires a special tool to pull the valve. If you don’t know what you’re doing, you may want to send your Autococker back to the shop (WGP or custom shop of your choice) to have the cup seal replaced.

  • Blown/damaged valve-guide O-ring: If you pull your valve out and find that your cup seal is perfectly fine, check the O-ring that sits around the front edge of the valve guide (the main body of the valve) and replace it if damaged. As this is not a moving O-ring, it doesn’t commonly get damaged during normal use. Look to it as the problem if you have recently had the valve replaced or repaired as it is commonly damaged when the valve is pulled out or installed.

  • Blown shaft O-ring on RAT valve or other custom valve: If you have a custom valve that has an extra O-ring on the shaft of the cup-seal stem (the Shocktech RAT valve was the first valve to include this feature), check it for wear or damage as well if you are having barrel leaks.

  • New cup-seal: If you have a new Autococker, or you’ve just had the valve or cup-seal replaced, you may find that you have a slow leak down the barrel when you first gas the paintgun up. This problem is particularly prevalent with some aftermarket valves with very hard cup-seal materials (the Tornado valve is notorious for this). The problem here is usually that the new cup seal material has not yet broken in to perfectly seal against the front edge of the valve guide. This will go away in time as the face of the cup-seal wears in. To seal things up and hasten the valve’s breaking in, turn up your input pressure until the valve seals, then cycle the ’gun a few hundred times. You should then be able to turn the pressure back down and keep a good seal.

  • Improperly-installed valve/valve-spring: If you’ve just had your valve replaced or repaired and you are now getting a vigorous leak down the barrel, another possibility is simply human error. If the valve isn’t in straight, or the valve spring is kinked or at a funny angle, the cup seal may not seat flush against the front of the valve guide. Pull the valve and reinstall it taking care to ensure everything goes in straight.

  • Make sure ’gun cocks with each shot: Similar to #1 above, if your hammer doesn’t catch the sear with each shot, it can end up staying forward holding the valve open and allowing air to vent down the barrel. If you find that your Autococker occasionally skips a shot and vents down the barrel until you pull the trigger or pull the block back by hand, you’re probably experiencing hammer slip-over. This is the case where the hammer slips over or doesn’t catch the sear, allowing it to stay pressed forward against the valve. This is usually be caused by the Autococker being mistimed (for timing directions, read my previous article from PGI June 1998, No. 111, or at my web page: If you find that your Autococker is properly timed but are still experiencing this problem, your sear and/or lug is worn so much that there is no longer enough friction for them to catch when the hammer is cocked. Replace your lug first — it’s cheaper and more commonly is the culprit. If changing the lug doesn’t correct the problem, you’ll need to get a new sear.

  • Operating pressure too low: If you find that your Autococker initially seals up properly, but the first time you pull the trigger it fires and vents vigorously down the barrel without cocking, your input pressure may be set too low. With a low input pressure, the free rush of air through the valve may be such that not enough is left to operate your autococking system. Try turning up your input pressure (using the regulator in your vertical ASA) to assist in closing the valve and allowing more pressure to run the ram. If this problem presents only after a few shots during rapid fire, you may have a problem with your air system. Check the regulator in your vertical ASA or your nitrogen system for bad O-rings or seals that may not be allowing it to recharge quickly.

  • Paintgun is not cocking: If you’re having problems like in #9 above, but increasing the input pressure has not lternately, you may have a flaw in your autococking system (eg. blown regulator, blown ram, etc.) or a serious problem with your timing such that the ram is not being activated to cock the hammer back. Check your front-end components and timing for problems.

3-Way Valve Leaks

  • Frozen O-rings: If you shoot CO2, your Autococker has been working just fine, and you’ve just developed a new leak from the front, back, or both ends of your 3-way, there’s a very good chance you’ve gotten some liquid CO2 into the valve and frozen up the O-rings. This is a temporary state and it should seal back up once the liquid is cleared and the O-rings warm back up. To prevent this from happening in the future, you should take measures to prevent CO2 from entering your Autococker using such things as remote systems, expansion chambers, pressure regulators, and anti-siphon tanks. Keep in mind that when liquid CO2 comes in contact with the O-rings in most 3-way valves, the seals swell and stiffen the valve’s action as well as making it much more prone to failure in the future.

  • Dry O-rings: Another possibility when you get a new leak, particularly if it starts slowly and gradually gets worse, is that the valve’s O-rings are dry. You can run a little oil through the paintgun via the ASA or you can just put a drop or two in the front of the valve with the ’gun degassed and pull the trigger a few times to work the oil through.

  • Pressure too low: With the preponderance of super-smooth aftermarket 3-way valves on the market, this has become a very common problem. Aftermarket valves often have looser fitting O-rings to allow for smoother action. As a result, they don’t make very tight contact with the inner walls of the valve. The ironic result is that you actually need a higher pressure in the valve to allow the O-rings to seal properly. In some cases, this pressure can be so high, that it’s actually quite a bit higher than required to run the ram and cock the paintgun. If your Autococker is properly timed and shooting well apart from a persistent leak from the 3-way regardless of trigger position, try turning up your front-end regulator (Sledgehammer, Rock, Jackhammer, etc.). That will often seat the O-rings more tightly and stop the leak.

  • Timing rod too short: Another very common cause of 3-way front-end leaks results from everyone trying to time their own triggers as short as humanly possible. Commonly people will set their timing rods very short to get the 3-way to switch early in the trigger pull. The result is that they don’t allow the 3-way piston to move far enough forward to seal reliably and a slow, intermittent leak from the front of the valve. This usually presents as a slow leak from the front of the 3-way that goes away when the trigger is pulled and held back (assuming you don’t have other timing problems or bad O-rings in the valve). Some will also find that they can make the leak go away by tapping the side of the timing rod (this can nudge the O-ring in just tight enough to create a good seal). The fix is very simple. Lengthen the timing rod until the piston is far enough forward to seal reliably when the trigger is all the way forward. Note: this problem can be more prevalent in valves that have been overpolished and in some poorly-designed aftermarket 3-ways. Palmer’s QuickSwitch is one valve that is notably and impressively resistant to this problem.

  • Bent or kinked timing rod: Not only does the timing rod have to be long enough to allow the 3-way to seal forward, it also must be perfectly straight and in-line with the 3-way to work properly. If the timing rod is bent off to the side it will bend the 3-way piston to the side as well. This increases friction (making for a stiffer trigger pull and causing the 3-way to stick) and pulls one side of the piston O-rings away from the valve inner wall, allowing it to leak. This most commonly occurrs with Autocockers that have aftermarket timing rods with aluminum couplers. The aluminum coupler does not fit the stainless steel rod very well, so when you tighten the set screw down after adjusting the rod length the coupler kinks off to the side. If the Autococker is gassed up while you’re doing this, you can actually hear the leak start and stop as you tighten and loosen the set screw. There are a couple fixes for this. First, you can just lengthen the timing rod further to force the O-ring further forward to seal more tightly. If you’re trying to get the shortest possible trigger pull, you’ll probably want to get a tight-fitting, all stainless steel threaded timing rod that does not kink when tightened in place. Both LAPCO and P&P make excellent aftermarket stainless timing rods. The new stock threaded rods on Autocockers and STO’s are superb as well.

  • Timing rod bumping trigger-frame: The timing rod can also be forced to the side by bumping against the trigger frame. Some aftermarket timing rods are not bent sufficiently sharply where they turn to go through the hole in the frame and trigger. When the trigger is all the way forward, the bend of the rod may press against the front edge of the hole in the trigger frame and be pushed out to the side, causing the same kind of leak as found with a kinked timing rod. There are quite a few ways to correct this problem. Obviously, you can buy a timing rod that is bent sharply enough not to bump the trigger frame in that way. You can grind away either the rod or the trigger-frame where the parts are bumping together. Finally, if a short trigger pull is not a priority, you can just lengthen the timing rod to the point where the 3-way bottoms-out against its forward-most position before the rod moves far enough forward to bump the frame. This final option is only possible in 3-ways that have a forward stop (the stock valve, Palmer’s QuickSwitch, KAPP’s 3-way).

  • Too soft trigger-return spring/trigger-binding: As with the too-short timing-rod, any time the piston doesn’t go far enough forward to seal in the front of the valve, the 3-way will leak from it’s front end. If your trigger-return spring isn’t strong enough or something else is causing your trigger to stick back, you will have 3-way leaks that go away when you pull and hold the trigger back, and when you actively push the trigger all the way forward. To fix these leaks, install a stiffer trigger-return spring or correct the cause of the binding.

  • Blown/damaged piston O-rings: The thing that everyone thinks of first is actually probably the least common cause of 3-way leaks. 3-way piston O-rings actually only very rarely go bad. If you have a bothersome 3-way leak that just doesn’t go away no matter what you do, try replacing the piston O-rings to see if that clears up your leak.

  • Blown/damaged ram O-ring: Now we’re getting to the real zebra. You can have a persistent 3-way leak as the result of a blown piston O-ring in your ram. What you’ll find is that your 3-way will leak from the back at rest, but switches to a front-leak when the trigger is pulled and held back. If you have that funky leak pattern and you’ve tried everything else to eliminate the leak to no avail, try swapping rams to see if that clears it up.

Other Leaks

  • Low Pressure hose leaks: If you are having a slow leak around the small, low pressure hoses at the front of your Autococker, they’re probably just too stretched out to seal properly. You can usually correct this by pulling the hose off of the barb, trimming the loose end with a knife or scissors, and shoving the clean end back onto the hose barb. You can sometimes run into a situation where the hose you’re using it actually too big for the hose barb on one of your front-end pneumatic components. If this is the case, you can get new, smaller ID hoses that fit more tightly, or your can get a set of hose clamps. Hose clamps are the small metal (brass and aluminum are most common) rings that fit over the hose and are shoved down over the barb after the hose is in place. These result in a tighter fit and a better seal.

  • Blown low pressure hose: If one of your low pressures hose pops off just once, it’s probably not a big deal. Just trim the end of the hose as described above and put it back in place. If you find that your low pressure hoses pop off very frequently, it may be because you have loose hoses that require hose clamps to stay in place (see above), or it may be that you have your pressure set too high. Try resetting your front-end regulator (Sledgehammer, Rock, Jackhammer, etc.) pressure to the lowest point that still allows your Autococker to cycle properly. If you find that your hoses blow off frequently regardless of where you set your pressure, you may have a blown regulator that is allowing full pressure to pass through. Replace or service your front-end reg to correct this problem. Finally, if you shoot CO2, your hoses can blow off if any liquid makes it past your front-end regulator. I strongly recommend the use of hose-clamps if you shoot CO2.

  • Front-block screw leak: Though this is very uncommon, you can have slow leaks around the edge of the front-block screw or the front block where it meets the ’gun body. You’ll really only run into this if someone has recently worked on your front block, taking it off or replacing it. There are O-rings on the front and back face of the front block that seal around the front-block screw. If one of these O-rings is damaged, you can get leaks around the edge of this screw or at the junction of the front-block and body. Unscrew the front-block and replace the damaged O-ring to correct the leak.

  • Leak at the ASA: These leaks can occurr at any ASA — vertical, bottom-line, or remote system. Most commonly they’re the result of a bad O-ring on the fitting or tank you have screwed into the ASA. Try replacing that O-ring first. Some aftermarket fittings actually don’t screw into the ASA far enough to seal up properly. If this is the case, you’ll either need a new ASA or a new fitting that screws in far enough for the O-ring to seal. Keep in mind that some tanks have pin valves that can start to open before the O-ring seals completely. Even if air starts to vent, screw the tank in the rest of the way quickly to see if it eventually seals up.

Every Other Autococker Problem You Coud Ever Hate to Have

Velocity Problems

Too Low/Too High

  • Bolt upside-down: If your ‘gun seems to be working properly but isn’t firing paintballs, check your bolt. One of the most common, simple problems is people installing the bolt upside-down.

  • Out of air: Sometimes people don’t check their HPA or CO2 tank. If you can’t get enough velocity, check to make sure your tank isn’t empty.

  • Improper velocity adjuster setting: First things first. If your velocity is too low or too high, give the velocity adjuster a twist. Take out the cocking rod under the bolt at the back of the ‘gun. Insert a 3/16" allen wrench through the lower hole in the back-block and turn the screw in front of it. Clockwise increases tension on the main spring and increases velocity. Counterclockwise does the opposite.

  • Mainspring too stiff/soft: If your velocity adjuster doesn’t allow you to get the velocity high enough or low enough, you may have a mainspring that is too soft or too stiff. This is most likely if you have a custom valve, or aftermarket hammer kit. Take out your bolt, cocking rod, back-block, and velocity adjuster to get to the mainspring. Replace the spring with a stiffer one to get higher velocity or a softer one to get a lower velocity. Many companies sell custom spring kits for the Autococker so they shouldn’t be too hard to find.

  • Incorrect input pressure: Your velocity problem can also be due to your input pressure. All Autocockers come with the WGP inline regulator, that should be properly set at the factory to allow you to get good velocity by just setting the velocity screw at the back of the ‘gun. If you’ve had custom work done to the ‘gun that involves the regulator, hammer, spring, valve, or timing, this can change. Unfortunately, there is no simple equation for setting your input pressure as valves have a bell-shaped velocity profile where velocity will increase with increasing pressure, but only up to a point. After that point, further pressure increases actually close the valve faster causing a decrease in velocity. My personal favorite way to set the input pressure for most ‘guns (the Tornado valve is a major exception) is to set the velocity adjuster to the mid point, then adjust your pressure regulator to the point where you get the highest velocity. In other words, start with a low pressure and adjust it up until your velocity maxes out and starts to drop again. At this point you are getting the highest possible flow through your valve. Now use your velocity adjuster to turn your velocity back to field-legal limits.

  • Valve spring too stiff: Another possibility when you’re having a hard time getting sufficient velocity is that your valve spring is too stiff. Installing a softer spring allows the valve to stay open longer and allows lower pressure operation and higher velocities. Conversely, if your efficiency is terrible your valve may be staying open way too long and might be improved with a slightly stiffer valve spring. Changing this spring requires taking the valve out, and thus requires a special tool, a lot of work, and retiming the ‘gun. I only recommend this for those experienced with the inner workings of the Autococker.

  • Improperly installed valve: If you’ve just had a new valve installed or had to replace your cup seal, new velocity problems can be caused by an incorrectly installed valve. The most obvious error is if the valve is installed upside-down. Another possibility is if the valve is a bit out of alignment, not allowing completely free flow. Try reinstalling the valve to see if that helps.

Erratic (Inconsistent)

  • Loose valve jam nut: This is one of the rarest causes of velocity problems, but it’s probably the most serious so I mention it first. If you are experiencing wide velocity fluctuations (+/- 30 fps or more) no matter what you do, find a quiet place and tip your ‘gun back and forth and listed for a clicking sound like something falling back and forth between the hammer and valve. If you do, you may have a loose jam nut. The valve is held in by two screws; one from below, and the jam nut which screws in behind it. If the jam nut comes loose, it can bang around in the space between the valve and hammer, destroying the threads it is supposed to be screwed into. If these threads are damaged, it can mean a very expensive fix or complete loss of your Autococker body.

  • Poor paint quality: One of the most common causes of poor velocity consistency is not the paintgun at all, but rather the consistency of your paint. If you have a case of paint where the paintballs are not all the same size, they aren’t all going to fit the barrel the same, so each shot will get a different amount of push. This also happens if your paint is out-of-round — velocity will depend on the paintball’s orientation when it drops into the barrel. You can check this by seeing how several different paintballs from your case fit your barrel.

  • Poor paint-barrel match (roll-out): If your barrel is much bigger than the paint you are shooting, the paint can roll part-way down the barrel before you pull the trigger. Velocity will depend on how far the ball has rolled out before you pull the trigger. The best way to fix this is to use a tighter barrel or larger paint so the paint can’t roll out. If you’re stuck for the game or the day, just make sure to keep your paintgun level or tilted up when chronoing.

  • Leaking regulator seat: If your paintgun shoots low on the first shot, but climbs when your rapid fire, or if you have an older Autococker (1996 or earlier) and you find the velocity gets higher the longer you wait between shots, you may have a bad seat in one of the regulators handling input pressure to the ‘gun. What happens is that the regulator quickly recharges to the set output pressure, but slowly leaks full tank pressure through to the gun. In new guns, this high pressure in the large valve chamber closes the valve too quickly, resulting in low velocities. When you rapid fire, the regulator's slow leak doesn't allow it to climb much past set pressure between shots. In older guns with their small valve chambers, the higher pressures associated with longer waits between shots result in higher velocities. To check this, gauge your in-line regulators and air system to see if they’re holding a consistent pressure. If the pressure creeps up past the set-point, replace the regulator seat.

  • Dirty regulator: If you find your velocity dropping off when you rapid fire (shoot-down), your problem may be a dirty input pressure regulator. A dirty reg seat or piston can cause the reg to refill very slowly. Gauge your regulators to make sure they’re recharging quickly and have them serviced if they aren’t.

  • Restricted flow: Another common cause of shoot-down is if there is a restriction in your gas path to the ‘gun. Check your hoses and connections to make sure there aren’t any kinks or crimped ends on your Micro-line. Replace any filters in your gas path as those can get clogged over time. Check your on-off valves to make sure they’re clear of debris and have intact O-rings. Finally, some remote systems with on-off knobs can actually be screwed down so far that they occlude the gas flow out of your CO2 tank. Make sure not to turn them in too far.

  • Improper timing - too much overlap: If your Autococker is timed with the cocking point in the trigger pull right on top of or in front of the point where it fires you can get some velocity inconsistency (as well as blow-back) if you pull the trigger slowly. See my previous article on timing the Autococker to correct this.

Timing Problems

These troubleshooting tips cover all the problems you could have getting your Autococker properly timed that weren’t covered in the original "4 easy steps to a properly timed Autococker" article.

Sear won’t catch:

This is the problem you have when the lug in the hammer slips over the sear rather than catching it when you release the trigger. This can result in a number of symptoms. The ‘gun could cycle but not fire a paintball. The ‘gun could be cycling but only fire sporadically. It could be firing (at a very low velocity) when the trigger is released rather than when it’s pulled. You could experience the "double shot" syndrome where it fires once on the trigger pull and once on the release, followed by a trigger pull where the ‘gun doesn’t fire at all. In all cases, you’ll notice that the cocking rod at the back of the ‘gun will often not stay cocked back when the trigger is released. There are several occurrences that can lead to this problem.

  • Lug set too short: This is a plain and simple timing problem. If your lug is set very short to allow the Autococker to fire very early in the trigger pull, there is not a lot of lug metal catching the sear. If there is only a tiny amount of lug catching the sear, it’s very easy for the lug to slip over. Screw the lug down further to push the fire point of your trigger pull back and give the sear more lug to catch when you release the trigger. Note, this changes the timing, so you may need to adjust your timing rod to get the cocking point of the trigger pull back into the correct relationship with the fire point. Read my timing article for more information on this.

  • Sear/lug worn out: With some custom triggers that are set for a very soft release, the friction between the sear and lug is crucial for them to catch, sometimes even more so than the overlap between the lug and sear. If your ‘gun is properly timed and the springs don’t seem to be the problem, check your lug and sear to see if the contact surfaces have been polished out to a mirror-like surface. If so, install a new sear or lug as needed.

  • Sear return spring too soft: If the spring in your grip that pushes the sear up is too soft, it can allow the sear to be bumped down too easily by the lug. Either stretch the existing spring or install a stiffer spring to correct the problem.

  • Main spring too stiff: The mainspring behind the hammer is what is pushing the hammer forward, and thus is the spring that determines how hard the lug presses against the sear when they’re trying to catch. If you have a very heavy mainspring it can push the lug right past the sear (overcoming the sear return spring. Install a softer mainspring to correct this problem. Note: installing a softer mainspring may require you to change your input pressure to get sufficient velocity.

  • Block too short/cocking rod too long: Here’s a simple one. Check to make sure your back-block can physically move far enough back to cock the ‘gun by pulling the back-block all the way back to see if the ‘gun will cock. If not, either shorten the cocking rod or unscrew the back block a turn or two until the ‘gun can cock properly. See my timing article for more information on how to do this properly.

  • Front regulator set too-low/starving out: You can also run into this problem if your Sledgehammer (Rock, Jackhammer, or whatever you have) regulator isn’t providing enough pressure to cock the ‘gun. Try turning the pressure up.

  • Blown regulator: If your Sledgehammer (or other front-end reg) is damaged and not recharging fast enough, you can run into this problem when rapid-firing. If this is the case, have the regulator repaired or replaced.

Cocking before firing ("It won’t shoot.")

If your Autococker is not properly timed, you can have a situation where it is activated to cock the back-block before the hammer is released. There are two ways to fix this, both covered in more detail in the Autococker timing article.

  • Lengthen timing rod: By lengthening the timing rod, you push the cocking point further back in the trigger pull.

  • Shorten lug: By screwing the lug further up into the hammer, you cause the Autococker to fire earlier in the trigger pull.

Ram doesn’t activate/back block stuck forward or back

  • Trigger-return spring too soft: Probably the most common cause when your back-block doesn’t come back forward all the way is that your trigger is not returning all the way to switch the 4-way valve back. This usually happens because someone has done a trigger job in which they’ve installed a softer trigger-return spring. If you install a spring that is too soft, it won’t provide enough force to switch the 4-way when under pressure. Install a stiffer trigger-return spring to correct this problem.

  • Trigger-stop set in too far: Autocockers with aftermarket .45 frames and trigger jobs can have an extra screw installed called a trigger-stop. The trigger-stop is used to limit backward travel of the trigger when the pull is shortened. If the trigger stop is turned in too far, it can stop the trigger’s backward movement before it has the chance to switch the 4-way and cock the ‘gun. If someone has just been working on your trigger and it suddenly doesn’t seem to be cocking the back block, try backing your trigger-stop out a turn or two to see if that frees things up. Note: this is also a strong possibility if the ‘gun sometimes seems to cock properly, but other times the back block hardly moves at all. This is because the momentum of the trigger pulling the timing rod back can sometimes be enough to carry the rod back just far enough to switch the 4-way on some shots. Make sure that the ‘gun fires and cocks properly when the trigger is pulled very slowly to ensure your trigger stop is allowing enough travel.

  • Timing rod slipped loose/backed out: If your trigger seems to be moving freely, but your ram is stuck in one position, check your timing rod. Old-style stock timing rods didn’t screw into the coupler, so if the retaining screw came loose the rod would just slide back and forth in the coupler without activating the 4-way valve. Reset the timing rod position and tighten the retaining screw back down. Also consider getting a new, threaded timing rod.

  • Timing rod way too long: If your timing rod is set far too long, the point where it would switch the 4-way valve may be beyond the point to which the trigger plate is physically capable of moving back. This is similar to when the trigger stop is set in too far. To fix it, shorten the timing rod. See my timing article for more information on how to properly set the timing rod length.

  • Regulator set too low: If your Sledgehammer is set too low, it may not provide sufficient pressure to cock the ‘gun so the back block only comes part-way back. Turn the pressure in the front-end reg up until the ‘gun cocks properly with each pull of the trigger.

  • Blown regulator: Just like if your Sledge is set too low, if the front-end reg is blown out and not passing enough/any air the ram won’t be able to cock the ‘gun. The difference is that turning the pressure up won’t correct the problem. Have your reg serviced or replaced.

  • Swollen 4-way O-ring: This is mostly a problem for people who shoot CO2 through their Autocockers. If some liquid CO2 gets into the ‘gun, it can cause the O-rings in your 4-way valve to swell. These swollen O-rings cause the 4-way’s action to stiffen up significantly and can result in your trigger return spring no longer providing enough force to switch the valve. Replace the tiny O-rings on the valve’s piston to correct this problem.

  • Damaged ram: If your ram has a blown out seal or is jammed up with crud it can have trouble cocking the ‘gun. With the ‘gun degassed, manually pull the back-block back and forth to see how stiff the ram’s action is. If it is very stiff and sticky, consider having your ram repaired or replaced.

  • Out of air: Your velocity should be more of a clue to this problem, but if you’re just dry-firing the ‘gun and it stops cocking properly, check your air supply to make sure you haven’t emptied your tank.

Feeding/Ball breaks

  • Short stroking: By far, the single biggest reason people have chopping problems with their Autocockers is because they short-stroke the trigger. That is to say, they pull the trigger far enough to release the hammer, firing a paintball, but don’t carry the trigger all the way back to complete the cycle. You usually get the 4-way to start to switch, but don’t deliver enough air to the ram to fully complete the cycle, partially feeding a paintball and chopping it in half. The best fix for this is to learn proper Autococker trigger hygiene. Pull the trigger ALL THE WAY back with each pull. Don’t fan the trigger (no one should ever fan the trigger on any paintgun - it’s stupid and pointless). In time, your finger will learn to shoot fast without short-stroking. Trust me, it’s worth it.

  • Barrel too tight: It’s always worthwhile to check how your paint fits in your barrel. If you find that your paint is extremely tight in the barrel’s breech you’ll want to find a looser barrel or smaller paint. A too-tight barrel is a sure recipe for broken balls in the barrel.

  • Bolt not back far enough (timing): I touch on this in much more detail in my timing article. If your bolt doesn’t come back far enough when the ‘gun cocks it can lead to chopped paintballs. Make sure that the bolt completely clears the breech with each shot. If it doesn’t, lengthen your cocking rod to allow more backward travel.

  • Trigger-stop set in too far: As mentioned above, if your trigger stop is set in too far, it can stop the trigger from completely cycling the 4-way valve. If it’s only slightly too short, it can cause the ‘gun to appear to be working OK, but not allowing the ram to open the breech completely or long enough. If your trigger stop is set to stop the trigger at the exact point where the paintgun cocks, try backing it out a bit to see if that helps correct your problem.

  • Cocking point way too far back: If there’s a huge gap between the firing and cocking stages of your Autococker’s timing, it makes it much easier to short-stroke the trigger. If you find yourself short-stroking a lot, you can probably reduce it somewhat by closing the gap in your timing. Either lengthen the lug or shorten the timing rod to accomplish this.

  • Not using agitated hopper/dead batteries: An agitated hopper like the Viewloader Revolution is an absolute necessity with high-end paintguns that don’t shake very much and which can shoot very fast. The Autococker is no exception. If you have an agitated hopper but are suddenly getting a lot of breaks, make sure you have fresh batteries. Near dead batteries will still run the hopper, but don’t break jams quickly enough during rapid fire.

  • Reg pressure set too low/dead ram (lagging): A lot of chopped balls can be the result of the ram lagging too far behind the trigger pull, not allowing the breech to stay open long enough for a paintball to reliably feed. Too low Sledgehammer pressure or a blown ram can be the cause of this. If your ram seems to be moving slowly, try turning up your reg pressure. If that doesn’t correct the problem, check your trigger-stop position (see above). If that doesn’t do it, repair or replace your ram.

Bolt Jam

Bolt jam is when the bolt actually jams up in place and can’t be budged. This is different from when the ram or trigger is the problem because the bolt can’t be moved at all. This usually occurs because a piece of shell from a broken ball has gotten wedged between the edge of the bolt and the inside of the body.

  • Grab back block and pull: Most of the time the bolt can be dislodged by just grabbing the back block and hauling back with all your might. The bolt will usually break loose and the ‘gun will function properly again. I highly recommend pulling the bolt out immediately after getting it loose and running a pull-through squeegee through the ‘gun from back to front to try to pull out any loose shell that might wedge the bolt in again.

  • Remove barrel and try to knock it out from the front: If, no matter how hard you pull, you can’t get the bolt loose by pulling the back-block, take off the barrel and try to knock the bolt loose from the front with a stick or squeegee. If it pops out, squeegee the area to remove any shell fragments before reinstalling the bolt.

  • Run hot water: If you just can’t get the bolt loose by pulling or pushing, you may have to wait until the end of the day and run hot water into the front of the bolt. The hot water should soften the gelatin of the shell and allow the bolt to come loose quickly.

4-way Problems


  • Clean & Polish: 4-way valves have ends open to the environment and can get gummed up with crud both from the outside as well as dirty air supplies. Cleaning the 4-way up can significantly improve smoothness of action if it has become very stiff. After removing the hoses and taking the valve off the front-block, you just need to pull the C-clips out of each end to remove the end-plugs and piston from the valve. If you have a brass 4-way, you can use Brasso (or other brass-cleaning solution) on a cotton-tipped swab to clean out the inside of the valve and end-caps. Make sure to clean it out with mild, soapy water after doing so. After reassembly, you should find that the valve’s action is much smoother.

  • Replace swollen 4-way O-rings: As mentioned in another tip above, liquid CO2 can cause the O-rings in some 4-way valves to swell and drag, causing much stiffer action. Replacing these O-rings corrects the problem.

Can’t reassemble 4-way

  • Replace swollen end-cap O-rings: So, you’ve taken your 4-way apart to clean and polish it, but now you find that you can’t get the end-caps back in far enough to get the C-clips back in place. Some people will give you very foolish advice like filing down the end-caps. Don’t do that. The reason your valve isn’t going back together is because your end-cap O-rings have swollen. You can get these at any hardware store. Replace them and the valve should go back together with no problems.

Well, that’s about it. I’ve really tried to cover everything I can think of that can go wrong with the Autococker that you can easily fix at home. If you come up with anything else I’ve missed, please feel free to e-mail me. Always remember the most important thing; the best way to keep an Autococker working well is to not mess around with it when it’s working well. People always run into the most trouble when they try to "tweak" the trigger on an already perfectly functioning paintgun.

All text and graphics at this site are © Ravi Chopra, 1999/2000