So what are we trying to do here? This really feels like a bot... I’m in Mobile format, so is there a spam link in the signature line or what? Between this one and the SBR vs. pistol vs. rifle thread this week, I really feel like these are just bots... otherwise it’s information which can be found a thousand other places online, and in better detail with less ignorant half-truths.

M4’s, M4A1’s, Commandos, etc are standardized model designations which include specific components - like barrel length - but for the civilian AR-15, the sky is the limit. I’ve built and rebuilt over 600 AR’s and uppers in the last ~20 years, with barrels from 7” to 29”, in a couple dozen cartridges from 17 Remington to 50 Beowulf... the possibilities for the civilian AR-15 might not quite be endless, but it’s pretty damned close.