...I swapped flash hiders....only there's one problem...
The rounds seem to be skimming the top of the flash hider (it's a non NM). I can see where it looks like the rounds have stripped the finish, or left copper streaks. In addition, the flash hider is a little loose now, and has some play / wiggle when gripped where as before there was none and it was tight...
How can the flash hider be installed crooked? The splines line up directly with the grooves in the barrel, they lock right in, you can't really adjust them!!
Any help would be GREATLY appreciated, as before my rifle was perfectly zeroed in and now it's a mess.
Thank you.
Apart from violating the old rule "if it works, leave it alone", how about the FS being a little loose now. When you installed it, did you have to use some force, such as a rubber mallet, to get it on, or did it slide on easily? Was it tight before because you tightened the castle nut, or was it already tight before that? The alignment of the FS will generally be determined by the splines if they're all tight in the barrel's grooves. If they're not tight, any wobble will have the FS shifting position from shot to shot. And even if it feels tight when you grip it, forces applied by the expanding gas are considerably more.
Moreover, consider where the FS contacts the barrel. The splines in the grooves contact at the back end of the FS assembly, but the muzzle passes through that and the space the castle nut fits into and presses against the rear of the FS itself. Inside that is a recess which receives and encloses the face of the muzzle. If the back and front ends of the FS are not perfectly aligned, that recess will push the front of the FS in some direction away from dead center. I had that happen with an SAI muzzle brake; you could see the brake slide on straight but when the muzzle reached all the way in, the brake would be forced to tip up. An SAI FS alignment gauge just barely made it through without contacting the mouth of the brake (which was thus still within spec according to SAI). But the mouth of the SAI brake is the same size as a
NM reamed FS; if it was the size of a
standard FS, I'm not sure I could even have gotten the alignment gauge in without damaging the barrel. And in any case, the bullets would have clipped the brake on the way out, just like you're experiencing.
The Reader's Digest version is that your new FS may be defective, causing an alignment problem and bullet contact.
...but I know there MUST be a way to install this flash hider so that there are no issues!
Well, maybe not
that FS. GI4 With my SAI brake, I eventually gave up and switched to an SEI USCG brake.