Video courtesy of and copyright owned by Discovery Communications* Mack takes a look at the XM307 Launcher/50 calibre machinegun. And has some fun blowing stuff up.:) The program was canceled in 2007. www.globalsecurity.org Category: Science & Technology Tags: future weapons xm307 auto-grenade launcher 50 calibre machinegun mark 19 40 richard machowiz navy seal iraq afghanistan