Crosman Air Pistol Trigger Rework

The Crosman 24xx Air Pistol series are very nice co2 Target Air Pistols, however they share the same trigger system that has a less than great response. When the gun is cocked and the trigger is slowly pulled, significant internal movement distortions are felt that really impact the aiming and firing of the gun. I applied the various remedies found on the web to my 2240, which helped a little but after looking at other gun triggers, I wanted to see if there was something that could be done with mine.

Be aware that the processes described here, once done, cannot be undone. This mod is tricky and could make your gun unstable, not cock reliably, and cause it to fire unexpectedly,

A good idea would be to acquire a new Striker and Sear beforehand so that you can put the gun back to original if needed.

Drill press and vise (or Bridgeport Milling Machine), rotary file or milling cutter bit, C-clamps, bar clamp end, files, propane torch, toaster oven, etc.

Here's how all guns work. When a gun is cocked, a Hammer or Striker is is put under pressure by a Spring and is held in this position by a lever called a Sear. When the Trigger is pulled, the Sear moves and disengages the Striker allowing it move "forward" and hit the thing that will cause the gun to fire. This illustration shows a center fire semi-auto pistol configuration, but the same basics apply to our project.

The way this disengagement happens makes all the difference in the performance of the trigger system.

This photo illustration shows the trigger system on this 22xx series of Crosman air pistols. The Sear is the slanted element that will rotate counter clockwise downward and release the Striker when pushed up by the Trigger.

Clearly this is a rudimentary trigger system. Owners of these guns try to improve the operation by polishing surfaces that meet, lubricating them, buying trigger components with little wheels, other odd gadgets, and trick springs (we'll talk about that later!). These actions help a little, but the real problem is how the Sear releases the Striker.

First is a crossbow trigger design from the 1300's. In cocked position, the Striker (bowstring) is under tension and held by the hook cut into the Sear. The Trigger locks the Sear from turning. When the trigger is pressed, the Sear is released and rotates counterclockwise and releases the Striker (bowstring), and launches the arrow. The key part is this notch.

The next picture shows a modern gun trigger mechanism that uses this same rotating sear. Note the notch. The other pics show various triggers that all have the common characteristic of a triggering point that has a very small seat. This allows the Sear to have a crisp, clean, break with minimum drag.

Here again is the stock trigger system. The sketch shows the interface between the Sear and the Striker on this gun. The Striker has it's beveled edge pressed against the angled face of the Sear by a spring when cocked. As the trigger presses up, the Sear teeter-totters down dragging and grinding it's way down that beveled edge. Not even close to a clean, crisp release situation. I polished and put all that Moly lube and whatever on that and it was still be a crappy, jerky, stuttering, release.

Here is the much upgraded trigger system. The thing to notice is that there is a greatly improved release mechanism with a small interface that will break cleanly. Someone else makes this other trigger system that also seems to solve the problem. Maybe I'll go for a "professional" solution if available some day, but for now...

I decided to try and alter both the Striker and the Sear to improve their interface. I want to reduce the amount of contact and the angle of contact between the two. Step one is to mill a recess into the Striker. I don't have a milling machine so I made one using my drill press. I will only be moving the Striker about 1/8" so what i did worked well enough for that.

To work on the Striker, I first heated it up to red hot hot and then let it cool slowly to anneal it to make it more machinable. Drill a 3/4" hole in a piece of wood and then cut it in half. Secure the Striker into the vise using the wood blocks to hold the work. Chuck in a milling cutter up tight to the jaw for stability. Set the height so that the bottom of the cutter lines up with the bevel. Clamp the vise to the drill press table with two C clamps. These should be firm but not tight tight to allow the vise to slide. I clamped the active end from a Pony bar clamp to the table to act as a "screw feed" for my Milling Machine.

Get this setup to work correctly with a few dry runs. Ready? Start the drill press. I wasn't sure about these Dremel cutters so I proceeded to very slowly feed the part into the cutter. I kept it oiled and surprisingly it cut into the steel Striker better than expected. Carry on feeding ever so slowly. I went about 1/8" into the Striker. As this machine is experimental, and you only have one shot, go slow!

Clean up your work and get the recess flat and insure you have a sharp, right angle edge. Polish it smooth. You can also polish side of striker.

These diagrams show first the original interface. The second diagram shows the material removed from the Striker with the milling process. The Sear has the indicated material removed by careful hand filing. Finally, the new interface shows a greatly improved action with a nearly vertical breakaway.

To get this as right as possible means going slow with the filing. Remove the end plug and Striker Spring so that you can apply pressure by hand to the Striker as you fit the notch in the Sear to it. I ended up with about 1/16" overlap.

Be careful not to go too far or the gun won't cock!!!

When all seems good, go ahead and re-harden the parts. Heat to red with propane torch then plunge into cold water. Then temper the parts at 400º for 3 hours then air cool. Is this the right way? I think so. If you know better, do it that way.

Altering these parts will place the Striker in a position farther forward when cocked. This means that the bolt will also be in a more forward position and so the space to load a pellet is decreased. There's still enough room but removing about 1/8" from the back of the bolt will give you more. Because the cocked Striker is now farther forward it will have a little less travel distance and so will hit the gas valve a tiny bit little less hard. I think this gave me 4 more pellets per cartridge. This was not a goal, just a consequence.

What the hell is happening with this stock Sear Spring? This Spring, of course, pushes up on the Sear for it to make contact with the Striker, but should it be bent and contacting the frame? When the Sear moves down to release the Striker, should the Spring be further distorted as it's compressed out of shape and go dragging and bumping along the frame? No!

The Spring needs to be straight. I tried a strip of polycarb, which was fast and easy, and worked, but it rubbed a bit. I now have a piece of 3/16" plex rod that works better. Notice back in Step 8 that I filed a small notch on the bottom of the Sear. This locates the top front edge of the Spring and keeps it from creeping rearwards when the Trigger is pulled.

Should you buy a $25 Adjustable Spring Gadget to adjust Trigger Pull? No! This gun comes with one already installed!

The Sear Spring is surprisingly malleable. I removed it from the gun and it measured 33mm. I squeezed it between my fingers a little and then measured it. It was shorter. I did this until I had reduced the length by about 10% or 3mm. This caused the Trigger Pull to go from 4.2 lbs. to 1.7 lbs. as measured with my scientific device. That was easy.

That is what the "Adjustable Trigger Spring Assemblies" do. Maybe they are a little more Precise, but this worked for me.

So there you go. I was amazed. No more of that clunk, clunk, scrape, maybe-somewhere-around-here-the-gun-will-go-off stuff. This trigger has turned out to have a slightly more crisp release than my Sig P220! Very Happy!

Now you can have a Single Stage Trigger that is set AT the Wall and then goes Bang. No more suffering.

***If you try this, let me know how it goes and if you have other insights, share those too. Thanx!