Ok really now, what are the differences?  Iwnt to colts website, and they dont show the ar-15, only the M16, and of course thats only available to "law inforcement" any input?

M-16 is the US Government designation for AR-15. I think Canada calls it the C7 for example.

The difference between the govt. and civilian models are the fire control group, and possibly a flash suppressor and bayonet lug.

All M-16s are AR-15s, but the reverse is not true.

Kyle

Bolt carrier, hammer, trigger, selector, and disconnector. The M16 also adds an auto sear.

Can I put an AR15 upper (bolt and all) onto a M16 lower and fire?

Sure, but it will only fire semi-auto

Unless it is a select fire......it is not a m16................

Wow, what happened to the web site?

The M16 is nothing like the AR15.

An M16 is a select fire weapon that is "defined" as an "assault rifle".

An AR15 is a semi-auto fire only weapon that is "defined" as an "assault weapon".

If you go to the Colt website to look for AR15 firearms you need to go to the "Match Target" link or the "Colt Acurized" link.

An M16 is not an AR15. An AR15 is not an M16.

You can put an M16 upper on an AR15 lower. You CAN NOT use the bolt carrier from the M16 on an AR15 for "legal" reasons.

Your AR15 lower must be a pre-ban lower in order to put a 100% M16 upper on it. If you remove the bayo lug, flash suppressor and the threads from the barrel it will then be legal to use on a post ban lower.
Why bother, just buy a complete AR15 upper in the style you want.

You should check out the rest of the AR15.com website, head over to the articles link at the top of the header.

Quoted: Joe, Technically, you're wrong.  In fact, all early M16s were also stamped "Armalite AR-15" along with "Colt M16".  Although most folks use AR-15 to mean "semi-auto-only" and M16 to mean "select-fire", that's not 100% correct. The term "M16" is merely a designation given by the military to what was originally a civilian design that anyone could buy.  Just like the military M9 is identical to a Beretta 92FS except for the markings on the slide.  M9 is merely the military designation. Again, we often use terms incorrectly because it's much faster then getting into a 20-minute discussion of the history of the rifle, and because most folks with know, more or less, what you mean.  But don't confuse language laziness with fact or truth. -Troy

In the early 60's, the AR15 was full auto and was a prototype.  As it was adopted, it became the M16.  As soon as it was adopted by the military, the full auto version manufactured as such was the M16 and was stamped that way. The semiauto version sold to the public has always been the AR15, with different companies applying variations to that name.  Not to say that there aren't AR15s that have not been legally converted to full auto, but they did not come from the factory that way.  There may even be some of the original AR15 full autos that the military accepted that had both markings, but again that was the very early days.  To say that the AR15 is the commercial designation and the M16 is the military designation is incorrect.  The AR15 is semiauto plus many other changes while the M16 is either burst or full and you will not find an AR15 in that configuration unless it has been modified or is old and rare.  To use the Beretta M9/92FS analogy is flawed because both pistols are semiauto while the rifles have completely different capabilities from each other.  Of course, this would not apply to LEO rifles, which various manufacturers sell to LE as the same model number as the non-LE semi only, but are in reality M16s.  That brings up a question about Colt listing their select fire rifle as an M16.  Can they do that since FN is the official supplier of M16s to the military?  Just wondering.  Why don't they in this case, call it the AR15, or do they think the M16 name would be more recognized?  Here would be a case were the AR15 and the M16 are the same.  But I believe the original question is referring to the difference between our AR15s and the M16.  Different rifles.