MGI: Modern Upgrades for Current Military Small Arms - Rackspace Bushmaster, Colt, stag, rock river, Remington, modular, gun, crafted, assault, maine, bangor, sales, online, quality, hydra, belt-fed, belt, clip, barrel, trigger, mgi military, versatile AR, mgi hydra, firearms, AR-15, AR15, rifle, Arms, firearm, Marck15, MARCK-15 Mack W. Gwinn, Jr. has been involved in the firearms industry for over 30 years. Listed below are some of his previous designs: Bushmaster Pistol, Rifle, & Submachine Gun QCB for .50 M-2HB FN Machine Gun SSP-86 Pistol 90 Round Magazine for M16 & Mini-14