[Sam56]

I have a few pro/carbines lying around, and Being the genius I am ( ), I decided to modify the living heck out of one of them. Here's my plan: I'm going to do away with the front grip. For a feeing system, I plan on JB welding a PVC pipe on it, similar to a stock class setup. Now, my real question is this: Is there a way that I could alter the internals (nothing too extreme) of the pro/carbine so that it would require re-cocking the marker after each shot? I guess the real question is, Is it possible to make a pro/carbine into a pump?

I know it's not practical. Though, I think it's possible. I've seen broken blow-backs that do this exact thing, they require a re-cock after each shot. I already have a pump handle modified so that it will fit on the gun and cock it properly, now I just need to figure out how to cause the gun to fail to "Blow-Back"


Any ideas?

[Cpt_Carnage]

jb weld the pin, and take off the hammer o-ring. ( i think, i take it the tippy "power tubes" are a lot like spyder tubes... they look as if they are...)

[pfizerreg]

If it's a pre-cvx valve I think you could just grind the rear valve nub down so that it doesn't release recock gas at all. The valve I'm talking about is the free-floating design with two pins, one on the front and one in back.

[spinny2559]

There were pump conversion kits made for the 98 Custom a short while ago.
Anyway, if you want to cut off the blowback gases there are 2 ways to do this. The first is to attach a washer to the back of the valve, and the hole in the center of the washer can only be big enough for the valve pin to fit through. Another way is to modify the valve pin or create a new one so it is wide enough to completely fill the hole in the back of the valve.

As for re-cocking, this picture should help give you some ideas.
http://server6.theimagehosting.com/i...hp?img=Picture 163.227.jpg

[Sam56]

So, when you say put a washer on the valve large enough for the pin to go though, do you mean a large washer or a small one? Or would it even matter? Could I use a thick rubber spacer as well?

Small:


Large:


Rubber thingy:


Which one would work the best? Thanks!

[spinny2559]

Let me clarify, it's not to be used as a spacer, it is supposed to be secured down to not allow any blowback gases to escape out the back. The hole should be just big enough to allow the pin to freely move, not bigger.

[Sam56]

ahh, I see. Thanks. I'll try and find one to use

[pfizerreg]

So - that's a CVX valve. You can't do the mod I suggested above.

What you may be able to try is to remove the o-ring from your hammer, and grind some of it away where that o-ring is seated normally to prevent blowback while still allowing the gas to come out.

[spinny2559]

Originally Posted by pfizerreg

So - that's a CVX valve. You can't do the mod I suggested above.

What you may be able to try is to remove the o-ring from your hammer, and grind some of it away where that o-ring is seated normally to prevent blowback while still allowing the gas to come out.

Won't work, blowback gases really need to be eliminated for the most part.

[Dead_Body]

So we're back to Spinny's idea. Sam, what I think you'll find is easier will be to cut a bit of sheet aluminium that is about the same thickness as one of your washers. Then drill a hole in it that is just barely big enough for the valve pin to slide through. It needs to be really close fitting but not grabby. If you don't have the right size of drill then go one size smaller and work the hole out bigger with a small round file, CAREFULL use of a Dremel or perhaps carefully work the hole larger using some fine sandpaper curled up into a round stick shape. Once it fits over the pin draw a pencil line around the plate using the end of your valve body as the circle template. Cut it down a little inside the line. Then clean the end of your valve body and one side of the disc really well with a good degreaser. Once done you can then epoxy or CA glue the disc to the back face. That'll cut off a lot of your blowback gas flow. From there remove the Oring on the hammer and if it still bounces or farts try grinding a couple of U slots down the sides of the hammer so the gases can flow past and out easily. The grooves should be something around 1/2 a pencil in size.

Another way that may allow you to seal off the blowback would be to take apart your valve. Then clean and degrease and sand the inside of the blowback passage hole with some coarse sandpaper. Then clean and WAX the valve pin or put some Dow33 on it. Just a very light smear. Put the valve back together and tap the valve pin a bunch of times to center it. Now carefully put some JB Weld down into the blowback passage and let it mostly cure. It should be hard but if you push on it with a small screwdriver it should dent. At this point take your valve apart again and carefully push the valve pin back out. You may have to grab the end with some pliers and twist it a little while you're pushing. Once it's out let the epoxy cure overnight. The next day or two days later use some fine sandpaper to open the hole up just a hair so the pin can float in the hole easily but it's still a very close fit.

Good luck and post more pics!

[Sam56]

I've looked at the valve and I can't figure out how to take it apart..

help? ^^

[spinny2559]

Taking apart this valve is no fun, but here is a guide which should help you.
http://model98.org/manuals/cvx.php

[gamer565]

https://www.pbnation.com/showthread.php?t=56&page=56

theres a pic of a pump tippman