Hey guys. I have a CMMG Sierra 22lr dedicated upper, which comes with a carbine forearm. I have a rifle forearm I'd rather use. Does anyone know what might be involved in performing such a conversion, if its possible at all?

Thanks!

I would have to measure mine, and its not close right now. BUT, the gas block on the upper is just clamped on. I know I can move mine forward to make it fit a mid-length hand guard but I have not tried a rifle length. The key is, the clamp on gas block and go anywhere the diameter of the barrel is right since it really isn't a working gas block.

We put midlengths too but I can say the rifles will be very close to working but your gasblock would nearly touch the crushwasher and may only clamp on about half of the barrel as the barrel steps down in diameter close to the flashhider out on the end. That would work fine but rifle length is really pushing it out close to the end of the barrel. Let me ask. Are the rifle lengths you have standard plastic of some sort or a freefloat of some kind,. If I ever put rifle length on the Sierra we would go with a freefloat with a top rail and just mount the sight on the handguard and eliminate the gasblock entirely.. That setup would be much better I think.  You could probably get a shorter length gas block too than the standard one on the CMMG.

I am sure you can make em work it just depends on if you would like the looks of the setup or not..

You have about 14.5" of barrel to work with. Take another couple inches off for the gas block.
Dave N

Thanks guys.  I went to take some measurements and mock things up this afternoon only to find I dont have a triangular handguard cap.  Its gonna be close, real close thoughGood thoughts, but this setup is a little weird.  I've got wood furnature I'm trying to make work.  

http://i193.photobucket.com/albums/z260/JasonWilliamPics/Guns/AR15%20BigJ1/ar1.jpg

The set came with a rifle forearm that I was considering trying out.  I think I'll pick up a handguard cap and just see...