I walked into Adco Firearms this morning and they had a BCM Mod4 hanging on the wall. I grabbed it and figure I'd give it a try.

Model No# BCMGFH762M4 - BCM CHARGING HNDL 7.62/308 MOD4 BK 083

Brought it home, dropped it in and it fit with no binding anywhere.

Either S&W changed something or BCM did because early reports from last year indicated that most M&P users had to modify it to get it to work. I did notice comparing the CH's side by side that the BCM I have doe not have a pronounced hump in the groove near the front like some early reports said needed to be filed down.

Anyway, I'm happy mine works unmolested. YMMV