FS2000 gas piston removal question?

[scoob_i_e]

First, I am perfectly well aware of this post:

http://www.calguns.net/calgunforum/showthread.php?t=152456

But what I am wondering about is whether modifying the FS2000 in this way will cause any harm to the rifle during firing? (Removing the gas piston and firing it.)

I realize rifles such as the FAL and M-14 can be fired this way for the purposes of launching a grenade (but the FAL and M-14 have a valve which can be closed for doing so.) And since modern designs use under barrel grenade launchers along with the FS2000 there is no valve to shut off.

So again, would this cause any damage to the rifle by firing it after modifying it in this way?

[TangoCharlie]

It will send some very hot and high velocity gas and powder debris directly into the gun. You'll have to take the gun apart and see what lies behind the gas cylinder to see what will be exposed to that.

[dchang0]

It will send some very hot and high velocity gas and powder debris directly into the gun. You'll have to take the gun apart and see what lies behind the gas cylinder to see what will be exposed to that.

Directly behind it is the main pushrod of the charging handle assembly that reaches all the way back to the bolt carrier assembly. The gases would vent around the tip of this rod (hardened steel) into the upper receiver, which is mostly polymer. There are large vents in the upper receiver, so the gases would dissipate freely.

Mostly, it would present a cleaning problem, as the upper receiver assembly is not meant to be disassembled as part of field stripping.

If anyone's going to go this route, my recommendation is to buy a spare gas piston and simply cut it with a Dremel tool so that it is too short to engage the pushrod. It would act as a plug that would prevent gases from going back into the upper receiver.

[scoob_i_e]

Thanks kindly for the info.

[tenpercentfirearms]

When I first did it, I left the gas plug in. Then I simply realized I could leave it out. Now guess where the gas is going? Straight out the front of the rifle and not back under the furniture.

[dchang0]

When I first did it, I left the gas plug in. Then I simply realized I could leave it out. Now guess where the gas is going? Straight out the front of the rifle and not back under the furniture.

Good point--one other thing that works is to turn the gas piston plug halfway between the two holes so that the vent is completely blocked off. Of course, you still have to remove the gas piston before doing so, so that you don't inadvertently knock the plug and turn your FS2000 back into a fully-functioning semi-auto rifle. And my idea would only work if you did use the cut-down gas piston idea I mentioned earlier.