A2 FSB gas bushing

T

tangolima

New member
My A2 clone with front sight base (FSB) overgases. Ejected brass lands at 1 o'clock. Not that I obssess with the ejection pattern, it is caused by the brass striking the defector. The shallow dents in the brass body are there to prove that.

There are adjustable FSB for a small fortune. There are drill and tap mods to make ordinary fFSB adjustable. I don't like either. For the latter, should the screw fail, the set screw could become a projectile flying sideways. Then I saw the gas bushing for mini-14, and I decided to give it a try.

Basically I tap #8-32 threads into the gas orifice. I drill a small hole into a 1/8" long stainless steel set screw to turn it into a gas bushing. The diameter of the hole regulate the gassing. The first one I tried is 0.07", which cuts down the gas passage area by half. Test fired and it worked almost perfectly. 4 o'clock means the ejected brass just misses the deflector.

That will do. The rifle's felt recoil is a bit better.

I may change mind when I practice weak hand. I may like the 2-3 o'clock ejection better. I'm going make a few bushings with bigger holes.

-TL

Sent from my SM-N960U using Tapatalk
 
This may be the neatest thing I've read in a long time. How is this idea not presented in a kit commercially?

I've hand drilled a Yankee Hill suppressor only gas block, but that process isn't reversable.
 
Thanks!

This mod is a bit too complicated to turn into a product. I do have a simpler version that I may test. It has much better chance.

However I doubt it will fly. There are plenty of adjustable gas blocks for AR. The market is too crowded. Users of FSB are the minority. Only weirdo like your truly would care to do such things.

-TL

Sent from my SM-N960U using Tapatalk
 
You must log in or register to reply here.
Back
Top