The TNTE XM177/GAU-5 Flash Hider & Grenade Ring is reproduction piece for your Retro carbine build. This flash hider has wrench flats, as well as flash hider cuts and grenade ring. The XM177 Flash Hider fits 5/8-24 threads are machined from 4140 heat treated steel and has a nitride finish. Flash Hider overall length is 4.3". This flash hider has a straight bore.
The shortest length barrel you can use with these and be legal for OAL is 12.5". Anything shorter after pin and weld will be an SBR. To correctly measure OAL you must insert a rod down the bore until it makes contact with the bolt face.
XM-177 Flash Hider
4140 heat treated steel
with wrench flats
3/32" hole pre-drilled for pin and weld