Well G22 – High Power Modification

Article by T.W.E.P.
Mar 11, 2009

This gun started life as a plain Well G-22. The barrel set is a 3/4 length (300mm) TN Parts 6.03mm ceramic coated barrel with a PDI hop-up. The receiver, bolt handle and scope mount rail are all factory parts.

I modified the gas bolt unit to improve flow. In stock form, the air passages are very small and restrictive. The main reason for this is that it’s meant to be used with 134a or green gas and filled like a gas pistol mag. The bolt has to store gas as well as house the entire firing mechanism. In addition, the gas ports on the valve stem are very small considering its size. The all brass construction limits the size of the ports since brass is a relatively soft metal and might break if the ports are too large.

To truly get the most from the gas bolt, you need to run an external gas source (CO2 or compressed air) with some kind of pressure regulator. Filling the bolt with 134a or green gas will not give you the shot to shot consistency that is necessary for long range accuracy. A compressed air or CO2 system with a regulator will keep the gas pressure consistent even if the temperature changes. Consistent pressure will give you consistent velocity, which produces a tighter shot group downrange.

The trigger box is completely stock since the hammer spring used for the gas bolt is light enough to feel like a stock G-22 spring. Also, since the microline connector is screwed into the bolt, the quick pull feature of the Zero Trigger would be wasted.  Considering how much power this gun puts out, I think it’s also a good idea to keep the safety.

As you can see, running an external gas supply does not mean having to carry a huge tank. My setup uses a 3.5 oz CO2 bottle to keep things light and compact. There is a 12 gram changer made by Component Concepts, Inc. (CCI). Many online paintball shops carry it, and it can easily be adapted to this setup.

The regulator I’m using is from a Shocker II paintball marker. It was originally a “female” ASA version with the low pressure (LP) spring pack that I have slightly modified to work in this setup. The stock spring pack has an output range of 0-700 psi, so you could use it with no problems as long as you don’t over-pressurize your gun. The main advantage of the LP springs is to allow the Regulator to have a better fine adjustment within the 0-500 psi range. What this means is that you can have better control over the exact pressure being put out from the regulator. With the 0-700 psi gauge, it is very easy to adjust the reg in 25 psi increments. Since velocity can be controlled by adjusting the input pressure, this allows the velocity to be set very precisely.

Attaching the regulator to the G-22 stock requires a bit of creativity. Since the G-22 stock is plastic, I drilled a large hole in the base between the magwell and trigger assembly as this was the only place that will accommodate its size. I also routed all the feed lines through the stock as to not get tangled during play. I had to make a special bracket to hold the regulator in place. Like I said, be creative.

To feed the gas into the bolt, I drilled and tapped the gas chamber/tank in the bolt to accept 1/8″ NPT fittings. These fittings are used for paintball guns, so they are easy to find. In this case, I’m using a microline fitting and 5/32″ (4mm) microline hose. Microline is typically rated for 800psi, so it works fine for the 300psi or less I’m feeding into the gun.

You can see where I had to mill the factory receiver to accommodate the microline fitting.

The actual length you need to pull the bolt back to cock the hammer in the gas cylinder is less than half that of the spring cylinder. The hammer spring in the gas cylinder feels about as heavy as the stock spring, so cycling the gun is fast and easy.

I did a bit of testing with various input pressures. Here are the results.
All velocities are with .43 gram BB’s.

Keep in mind these velocities are the result of EXTENSIVE valve work on the bolt. The stock gas bolt will not get the same results.