if unusually, heavily-armed. >> justin mcmillion: our muzzle break is the only kind that actually reduces recoil, muzzle rise, and flash. >> anthony: they own "jmac customs," a home business that designs and builds custom weapons and parts. >> justin: so this keeps you on target, makes sure that you're safe while you're shooting. put the mag in. >> justin: 3, 2, 1. [ rapid fire ] >> anthony: now, to be clear, these are fully automatic firearms. they cannot be purchased legally by individuals anywhere. but as they're in the business, these guys can apply for special, highly-vetted atf licenses for purposes of product development and testing. >> anthony: that was just really -- that was a lot of fun. i'm a child, what can i say? >> ashley: who wants to blow up pumpkins? ♪ >> justin: just mixed up a binary explosive. ♪