SpudFiles

So today I bought two crossman pump masters at Walmart for me n a friend and I opened mine up on the inside of the gun I found its operated by a hammer valve so here's what I wanna do I realized that when you pump it a few time and hit the valve pretty hard all the air comes out but when you tap it softer you can get around 10 burst of air depending on how hard you hit it so if I pump it around 30 times I can get a few shots before needing to pump it again basically it would be bolt action just how it was when I bought it but I dont need to constantly pump it. My theory is all I need to do is shorten the spring so there's less force behind the striker so the hammer valve only releases some air am I right??? So all I would need to do is recock it and load a bb to shoot again?

Also instead of using the built in pump to fill the air tank couldn't I make a external air tank that I'd fill to like 200 psi then I don't need to pump the gun ?

beastmode986 wrote:Also instead of using the built in pump to fill the air tank couldn't I make a external air tank that I'd fill to like 200 psi then I don't need to pump the gun ?

You are going to need a bit more than 200 psi....

In regards to the hammer part, instead of cutting up the spring, lengthen the area it travels in. Just epoxy a longer spring tube for it to travel in.

Instead of cutting the spring, replace it with a weaker one, then no modifications are need

Ok thanks! I assume this means my theory is correct ? Also why would I need more than 200 psi and by spring tube do you mean expand where the spring is house

Forget what warhead said about the tube, just put a weaker spring. But he's right about the pressure... I'm not sure about the volume or pressure of the stock reservoir but I'd say you need at least 400.

What you're describing is called an "air conserving pumper". It's been done, it works, and it works well.

Having it work is also a "tiny" bit more complicated than you think it is.

Finished! did it to both of them it works great I'm uploading a video to YouTube soon

Will be watching for it.

Gonna include a penetration test?

yes but that will be in a seperate video its a how to and in the end some dry firing but i will do a penetration test tonight or tommorow also my plans in the future are to tap the air chamber and pump housing to accept a 12 gram quick changer but would the pressure be to high and the how to is half way done up loading it started 20 min ago

I'll admit to being rather curious as to the shot count and power level you're going to get...will be watching. Best I've seen from one of these valves without pumping between shots is two shots around 500fps in .177 with 7.9grain pellets.

Have seen the front of the valves drilled and tapped for 1/8"npt and pressurized through there. It's safe if done correctly.

Some people build multishot pumpers from scratch.

What you want is more stored volume.
I'm not familiar with the exact valve but of there is any way of drilling out the aorchamber to hold more air that would fix it.

It will require more pumps but last more shots.

well first off my video didnt upload even though it said upload complete so now im uploading it again....
Anyway basically for future modification i want either a quicker way to fill it or more volume or both. Would it be possible to tap it to accept a 12 gram co2 quick changer or would the pressure be to high as far as a larger air chamber ,heres my idea first i would drill a 1/2 inch hole in the air chamber hopefully that wont be to big and then tap it to thread into 1/2 galvanized pipe in a 2 or 3 inch section then put on either an elbow and a 1ft section of pipe along with some fittings to make it acccept a 12 gram quick changer or i would screw a t fitting on it and add a 1ft section of pipe on each side one capped and one threaded for a quick changer.

would that work? im trying to get as much power as possible so what other upgrades could i do?also i noticed the sawed off one i made is more efficent but less powerful than the full size one.
would it be possible to make it semi auto?


ALSO thank you very much for all the help.

VIDEO IS UP
a damge test will be done later