I’ve seen your posts about the L1A1 rifle and I’m asking you for some help. I would like to change the original flash hider, for a new one like the Vortex. But they make only 9/16 x 24 threaded devices with left hand threads [for Metric FALs]. Where can I buy an adaptor, or do I have to transform the barrel? Thanks for your help. – Philippe
JWR Replies: The original L1A1 military-issue flash hiders are actually quite efficient. (The only exception is the short Papua New Guinea (“PNG”) variant flash hiders, which has about 20% more flash than with the standard “bird cage” flash hider.) Therefore, I’d recommend leaving your rifle as is.
But if for some reason you must put on a Vortex, then you’d have to re-thread the barrel. Keep in mind that this will detract from the resale value of the gun. If you do go aheabd nad have it re-threaded, then I suggest that you specify a 1/2 x 28right hand thread, for versatility. This is because there are lots of different 1/2 x 28 muzzle devices available. WARNING: You’ll need to get a .30 caliber specification Vortex (the one made for AR-10s), or have a .223 Vortex drilled out to at least .328″ (or any dimension slightly larger), for safe bullet clearance! Failure to do so would be catastrophic.