Pre-ban= Lefty loosie (threaded on only)
Post-ban= Probably 'pinned' on, heat it up w/ a MAPP gas torch, and it will come off (well, it should anyway [:D].
If it is pre-ban, and just 'wrenching' it off doesn't work, you could try heating it up a bit (perhaps it ended up w/ a bit of Locktite on it???)...than, follow above instruction.
WARNING: HEATING UP A FH, OR MB WILL RUIN THE FINISH ON THE WEAPON...(my personal PSA, so you don't call me up and say, Hey, Carree, you made me ruin my AR. Fix it.)
Anyway, good luck. ch
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