Can someone help clarify this for me?  I know what the difference is between the A1 and A2----not sure about all the others.

Thanks in advance! CR

As far as I know, it depends on if you're talking AR's or M-16's.

AR-15A1 (similar to M-16A1)
AR-15A2 (similar to M16-A2, namely in sights)
AR-15A3/A4 (both refer to flat-top receivers)
M4/AR-15 M4Gery (styled after the M4 variant of the M16 system with unique barrel, collapsable stock, and flat-top receiver)

M16A1 - full auto capable, old sight system
M16A2 - Three round burst, new sight system
M16A3 - Same as A2, but full auto capable
M16A4 - Three round burst, flat-top receiver

Now I'm confused.  That's what I understood, but my Armalite 20" stainless came in a box marked M15A2NM, and the serial numbers match, but the upper is configured exactly like the M15A4 (T), except for the fiberglass handguard and 4" longer barrel.  It's a 20" flat top with single rail stainless gas block, but the handguard is the free floater that looks like the standard and there were no sights on it.  Because of that, I thought I misunderstood what A2 and A4 meant.  

So what exactly do I have?  Does Armalite do special order guns for dealers, or could this be a prior year config?

Not this thread again [rolleyes]...

Your answer is here:

[url]http://groups.msn.com/TheMarylandAR15ShootersSite/whatisana1a2a3ora4.msnw[/url]