If Sig, Glock, S&W, and Beretta will sign on, it will REALLY put the pressure on them.
Of those, only Smith & Wesson is a major domestic manufacturer. Sure, the others have significant investments here, but only S&W is the name in that group that shouts out "American".
If that company would like to forever bury the Clinton-era agreement that tarnished its name, now is the time.