The Colt AR-15 is closely related to the military M16 and M4 Carbine rifles, which all share the same core design, first patented for use in the AR-10, featuring a gas-operated, rotating bolt (combined with an integral piston) instead of conventional direct impingement, operating system patented under U.S. Patent 2,951,424 by Eugene Stoner.[15][16]Huey » 09 Jun 2022, 8:55 am » wrote: ↑ I'm good. Keep posting. A good laugh is always cool in the mornings.