The M16A2, M16A4, and M4 are all select- fire, 3-round burst. The M4A1 in current use is select-fire, fully automatic.
The .223 was originally selected because of it's high velocity, low recoil, and because a rifleman could carry more rounds of .223 than 7.62/.308. Current 5.56 M855 is an effective anti personnel round (high velocity tumbling) at medium range. As a home defense weapon the AR15 is superior IMHO due to its better accuracy, better followup shot capability, and better maneuverability, not to mention the capability to mount a light, a supressor, and fast-acquisition CQB red dot sighting systems. Appropriate defensive round selection and an AR15 over-penetrates significantly less than buckshot (or handgun ammo, for that matter), either in tissue or sheet rock.
'04 MariStar 230VRS/MCX
Last edited by bigmac; 09-28-2013 at 08:49 AM.