I've seen several flash hiders that, when used with the A2 style crush washer, required more than a full rotation to index correctly at 12 o'clock (they originally indexed, finger tight, just shy of 12 o'clock). This is putting way more than the specified 15-20 lbs of torque that Colt recommends and even more than the 25-30 lbs that the KAC M4QD recommends.

I just installed an Armalite AR-10 flash hider with an Armalite crush washer. It only required a 90 degree turn but at least 90 lbs of torque was required to move that 90 degrees.

What's the story with over torquing flash hiders? I'm told it's a quick way to destroy a barrel/accuracy?