Marui GBB pistols

[Styrak]

Originally Posted by S_Okita

Id like to tack on a question about maruis, what if any mods are needed for propane?? ive read a lot about people saying you need hi flow valves and enhanced recoil springs etc. otherwise you run the risk of cracking the frame or the slide from the excess pressure.

I don't think you understand what highflow valves do. They allow MORE gas to run through the gun, increasing FPS of the BB and recoil of the slide.

[ap27]

You wouldn't need a high flow valve just to run propane in a stock marui pistol. If you add on a steel slide and a 200% recoil spring onto that pistol, then you would need a high flow valve as more gas would be needed to cycle the heavier slide and stiffer recoil spring.
I could be wrong on this, but I think if you go for a high flow valve you also need a stronger hammer spring to hit the valve hard enough.

[Jamroxorz]

Yeah i think you're right ap27, remember hearing that about the hammer spring.

[S_Okita]

Originally Posted by Styrak

I don't think you understand what highflow valves do. They allow MORE gas to run through the gun, increasing FPS of the BB and recoil of the slide.

i realise that much, just thought higher pressure = more back pressure (a larger valve will allow more volume but usually lower pressure) creating a harder recocking charge and that was the issue. For the most part what i gather is that i should run an enhanced recoil spring to absorb some of the shock, and dampers if possible and i should be ok. thanks.

[Styrak]

For what, propane in a TM gun? A stock TM can handle propane just fine.

[S_Okita]

yep. was just checking, wanted to be sure first dont want to explode my investment on the first shot, nor do i want it to be a constant problem to rebuild either.

[Kozzie]

Modern marui pistols are much more robust than they used to be. While not designed for it they hold up well to use with propane.

The common stock parts that MAY break on you would be the slide or the nozzel. This however is nothing to really worry about since those parts only cost around $10 each and are both easy to swap out.

[Slono]

Originally Posted by S_Okita

i realise that much, just thought higher pressure = more back pressure (a larger valve will allow more volume but usually lower pressure) creating a harder recocking charge and that was the issue. For the most part what i gather is that i should run an enhanced recoil spring to absorb some of the shock, and dampers if possible and i should be ok. thanks.

Actually, the opposite is true. You do not want to have a stronger recoil spring because your upper assembly will slam back into battery after the blowback action Stronger springs are only needed when you're running metal slides.

[Styrak]

Originally Posted by Slono

Actually, the opposite is true. You do not want to have a stronger recoil spring because your upper assembly will slam back into battery after the blowback action Stronger springs are only needed when you're running metal slides.

I like running an upgraded recoil spring with my stock plastic slide and barrel for the added snappiness. But that's just me.