forget it, man, Hard Rock's just a liar.
smg's suck uniformly, not enough power, no lighter or more compact than a good 223 carbine, no AP capability. all in all a STUPID choice. But then, so is a bolt action rifle. For ranges beyond the 500 yds that an AR 15 handles easily, the proper choice is a smithed UP BAR, in 300 win mag. It's plenty accurate enough, its 9 lbs and gas op means you dont get beaten up in practice, it has a threaded muzzle if you order it with the BOSS compensator, and it offers rapidfire if you need it. So there's no NEED of the smg, dummy, unless you stupidly choose a bolt action for long range, dummy.