[Uchahi]

I have always been interested in what the main differences are in the civilian models are? Do they all shoot .223? Who is the best to buy from? What are some very important information that I need to know about what I am buying?
M4-Shorter in length.
AR-15 - people really like this gun and I can't figure out why?
M16- I got nothing.

[jeepcreep927]

You don't have to worry about buying an M4 or M16 unless you have several, several, several thousand dollars kicking around. The M16 was adopted by the Air Force in the early sixties, then by the remaining branches to replace the M14. M16A1 is semi/ full auto, M16A2 is semi and three round burst with an adjustable rear sight and round handguards, there are other incarnations such as the M16A3 and M16A4 which are all based on the M16 with differences in the fire control group (full auto, three round burst etc.) and handguard configuaration.

The M4 is also a modification of the M16, with the differences being in barrel length and fire control group as well. There are variations of the M4 to boot, but the basics all boil down the original M16 lower receiver and the rest is relatively unimportant unless you're a Soldier or Marine.

The AR-15 is Colt's (purchased rights from Eugene Stoner/ Armalite, the original designer and company) semi auto version. AR-15 applies only to Colt's model, with other companies that produce similar (read that the same) rifles often using bastardized designations like A15, R15, etc. since Colt's has the rights to the AR-15 model designation.

There is tons of info here compiled by dozens of members about manufacturers, components, accessories and so on, ad nauseam.

[Uchahi]

So for a civilian ( no duh ) what should I be looking at? It seems like a Colt Ar-15?

[c3shooter]

Oh, my- where to start?

First, the AR-15 is actually a brand name. It usually denotes the full sized rifle. The military caliber is 5.56mm, which is SIMILAR to, but not the same as .223. You can shoot .223 in a 5.56, but shooting 5.56 in a .223 MAY give high pressure- bad ju-ju. The AR STYLE rifle is made in a VARIETY of calibers, ranging from .22 LR to .50 Beowulf. .308 and .243 are popular, as well as some of the 6mm rounds. Within limits of case length, you can also switch uppers, having multi-caliber capabilities from one lower.

M4- term USED to denote the shorter carbine, usually with a collapsable stock. The TRUE M4 is not available to civilians in the US, since it has a burst fire or full auto mode, and was made after the 1986 full auto transfer ban. The lookalikes are semi, and simpler a shorter rifle, little handier in close quarters, a little slower bullet due to shorter bbl.

M16- the military, full auto version. Due to the 1986 transfer ban, price on a legal, transferrable full auto M16 will make you weep. Last one I saw was about $12,000, plus the $200 transfer tax. Do not even THINK about converting a semi to full auto- you need a machine shop, and in the US the penalty for making an unregistered machinegun is 10 years in a Federal prison, a $250,000 fine, and loss of your girlish laughter.

You could have a HUGE rifle collection with nothing but variations of the AR style rifle- different calibers, different barrels, different sights, different actions, different materials- left handed models, even AR style pistols- and there are now gas piston (instead of gas tube) models. The variations would make a BIG book- I have just scratched the surface in this post.