View Full Version : M16 info

November 19, 2002, 06:44 PM
Lately ive been wondering what are the differences of some m16 rifles. Here is a list of different m16 rifles can anyone tell me the differences between any of them or if their the same. THx

M4 Carbine
M16 Commando

November 19, 2002, 07:09 PM
M16 origional design adopted by USAF in 1961

M16A1 Improved design with forward assist mech and numerous other small cahnges. Adopted in 1967

M16A2 Adopted in 1982. 800M rear sight, cylindrical handguards, 1:7 rifling, etc, etc 3-shot burst rather than full-auto

M16A3 Date of introduction??? A2 with removable carry handle/MilStd 1913 rail This gun came about after the M4 carbine was introduced.

M16A4 Not certain.

M4 14.5-inch A2 spec barrel, sliding stock, 3-shot burst, removable carry handle

M4A1 same thing, but full-auto rather than burst.

M16 Commando designation used by colt for most any sliding stock or fixed stock short barreled AR15/M16 throughout the 70s and 80s. Origionally refered to the Xm177 series guns that were never officially adopted by the Army.

For more detailed info, check out www.AR15.com

Jeff White
November 19, 2002, 08:35 PM
Good answer..one correction though:

M16: Original design. 1/12 twist light 20" barrel, triangle handguards, open 3 prong flash hider, safe-semi-auto fire control parts.

M16A1: Same as M16 except trapdoor buttstock, forward assist, closed "birdcage" flashhider and some internal changes.

M16A2: buttstock 5/8 longer, furniture made from different material, barrel is light under handguards, heavy in front. Round handguards, 800 meter click adjustable rear sight, square front sight post, 1/7 twist barrel, bottom slot in flashider closed, safe-semi-burst trigger group, finger swell added to pistol grip. Swell behind ejection port for brass deflector.

M16A3: Identical to M16A2 except for safe-semi-auto trigger group.

M16A4: Identical to M16A2 except flattop upper receiver with removable carry handle and 600 meter sight. Usually found with Knights Armament M5 rail adapter system on it.

M4 Carbine: Basically an M16A4 with a 14.5 inch barrel that has a cut milled in it in front of the front sight base so that the M203 grenade launcher can be attached. and a collapsible stock. The first M4s had fixed carry handles.

M4A1: Same as the M4 except has safe-semi-auto trigger group. Many M4A1s are being refitted with full heavy barrels. No M4A1s were procured with the fixed carry handle.

M16 Commando: Colt commercial designation for several different model carbines.

Both the M4 and M4A1 can be found in service with the Knights Armament M4 RAS. After the Army adopted the M16A2 in 1985 (3 years after the USMC who designed it) they stopped procuring any M16A1 spares that were applicable to both weapons. It's not unusual to find M16A1s with bits and pieces of M16A2 furniture or square front sight posts.



November 19, 2002, 09:03 PM

Thanks for the clarifications on the A3/A4 point. Those designations came around after I had left active duty and settled into my "short and light are the way the AR was ment to be" phase and I just haven't followed the rifle variants.

Origionally the M4 was introduced with fixed carry handles, but once the flattop was introduced, all of the older M4s were retrofitted to flattop config. A lot of people mistakenly believe that the A1 in the M4A1 designation refers to the detachable carry handle because it was the first widely issued flattop.

Jeff White
November 19, 2002, 09:13 PM
...because some commercial AR15 makers use it. The M16A4 is becoming more popular. I think the USMC just adopted it as a replacement for the M16A2. My son used an M16A4 in Infanrty OSUT last spring.

I have never actually seen an M16A3. Been told that some were made for the Navy. I doubt that there are too many in service.


November 19, 2002, 09:18 PM
Heard the thing about the civilian makers going with A3 as their variant classification for AR15s while guessing at what the military would choose to call the flattop variants.

SURE didn't help when Colt lists on their webpage the M16 A3s or some such garbage along with a majority of the other AR15 manufacturers. Funny thing was trying to explain it to others and having to tell them that Colt had it wrong, whoa nelly is that an ever loving pain and then to bring up the whole A4 thing.

Yes, the Marines just officially adopted the A4 to replace the A2. Article was on various forums about a week or two ago. I wonder how many of them will be new purchase rifles while how many A2s get reconfigured with new upper assemblies?

November 20, 2002, 06:46 PM
OK, it just got even more confusing. I was thumbing through the 1995-96 edition of Jane's Infantry weapons and they are quite explicit about the M16A3 (Colt AR-15 Model Number 901) being a flatop M16A2 with a full-auto fire pack. They correctly identify the M4A1 (Colt AR-15 Model Number 927) as being a flatop M4 with the full-auto pack. Does anyone have a link to a current TM on the M16 family? Also, does anyone have a link for the Marine Corp article on the M16A4? Curiousity killed the cat and all that.:)

November 20, 2002, 06:56 PM
See, thing that really screws it up, when was the last time Colt was a contract source for the M16s?

M4s, yes, but I was under the impression that FN was the main contractor for M16s. Is there a special consideration made with M16 A3s? If the M16 A3 is a cosmetic duplicate to the M16 A2, I could see where they'd come from FN only with a special trigger pack. If they are a flattop and cosmetically identical to the M16 A4, I don't know what to believe really(though I don't believe that it's the case that the A3 is a flattop).

What I do know is this, Colt long ago bought the trademarks to the AR15 name from Armalite. It's become a long standing tradition to associate "AR15" or "M16" with the Colt name. For the most part, the guns on the Colt law enforcement page could be type classed anything they wanted to for the purpose of civilian sale.

But not all of Colt's rifles are fitting with what the gov't. or military calls for in their specifications. An M16 A2 must meet a defined set of criteria before it will be considered an "M16 A2" by the military. Change the trigger group and it's likely the military changes the variation/classification to fit the new gun, M16 A2 to M16 A3 with new trigger group.

For civilian sales though, Colt can get away with calling both a "safe, semi, full" and a "safe, semi, burst" M16 an A2 variant simply because they are cosmetically identical. Same applies to the A3s that they sell. Civilian sales or variant designations don't have to follow military form, though they sure do like to try.

As for Janes, anyone else here think that Janes is wrong?

Jeff White
November 20, 2002, 07:33 PM
According to TM 9-1005-319-10 October 1998 and TM 9-1005-319-23&P complete with change 7 (Sep 01) the M16A3 is as I described.

Look in the manual depot link at the Maryland AR15 Shooters Site or the files link at [email protected]

I agree Janes is wrong. As far as I know Colt's is currently only producing M4s right now. I think the current contracts are keeping their production capability tied up. FN in Columbia SC is currently producing M16A2s and A4s. I don't have any idea who is making A3s.

There is also a program to retrofit M16A1s to M16A2 and A4 configuration. The M16A4 my son had in B-2/58 Infantry OSUT was one of these. The receiver was marked Colt AR15. The M16A1 stamp had been stamped out and it was then marked M16A4.


November 20, 2002, 07:47 PM
Cool. The last time I was running an active duty arms room we had begun to get FN produced M16A2s whenever we deadlined older peices (1992). Quality control was not great. Two out of the thirteen peices we received had to be returned. The most recent 23&P that I've got sitting around is a 91 edition with changes thru 96 and the M4 & M4A1s are covered, but not M16A3s or A4s.


When I was in OSUT in 89, my issue gun was an XM177E2 reconfigured and overstamped to M16A1 config. It's amazing what turns up in the depots. I also had a cherry condition HydraMatic A1 issued while serving in a MP unit and it was flawless. :eek:

Jeff White
November 20, 2002, 07:56 PM

You'll be unhappy to know that FN's quality control hasn't gotten any better. My Guard unit received 114 brand new in box FN M16A2s last December. They didn't really get a workout till AT in June. Out of the 70 or so we took to the field, we found 4 with the firing pin retaining pins missing, two that were missing the spring and detent for the rear takedown pin, and we had problems with the finish flaking off the lower receivers. These were NIB rifles. We literally unpacked them from the carboard boxes FN shipped them in.