AR folks? AR 10

Honestly I'd rather keep it simple. .308 is a versatile, proven round, and plentiful. If you look what happened after Sandy Hook you couldn't find any of the "designer" rounds, reloading supplies, whatever. Hell, half of the common rounds were MIA for basically years. If I need something bigger I'll whip out my .300 win/mag, anything else my AR15 will do. JMO.