m15-a1 vs. m15-a2 vs. m15-a3

[Caliber357]

Ok guys, I'm sure this has been asked somewhere else before, but darned if I could find it thru Google. What's the difference between the various types?

Oh yeah, one more quick question - I'm eyeing an Armalite m15-a2 for around $600 - is that a decent price for them? I seem to remember Armalite running around $800-$1000 back when I first got interested in Ar's.

Thanks in advance for your help!

[2ndChildhood]

Well, I just paid $759 for my new RRA A2 to give you a data point.

Very happy, it's a nice gun.

Somebody with more knowledge needs to comment on differences.

[Colorado Osprey]

There have been over 150,000 upgrades/changes from the inception of the M-16 to it's current production. It is the most tested and reliable weapon platform in use today.

Switching to the civilian version it mostly mimicks the military version, except of course being semi-auto and some changes in the bolt and trigger group. I am not taking into account barrrel contour/ profile or length.

The biggest and noticable changes to me are:
A1
5 position front site adjustment wheel
A1-style rear site...harder to adjust
Triangular hand guards
Never had tactical handguards with rails

A2
Addition of a forward assist to the bolt
4 position adjustment front site wheel
A2 800 meter rear site
Round handguards w/ addition of heat shields

An A3 M16 is not to be confused with a A3 AR-15
An M16A3 is a full auto/semi auto...no 3 round burst

A3
Upgrades of A2 plus the following
Removal of carry handle in upper receiver casting while adding a rail where the handle used to be.
Optional carry handle available

M4
All upgrades of an A3 plus the following
Cuts made in barrel extension lugs acting as a feed ramp
Different profile barrel
6 position collapsable stock as standard equipment

Obviously I have missed over 149,985 upgrades....please excuse what I've missed.
If anybody else wants to add more feel free....I will not be offended.

[Ice Pirate]

Found this site for you:
http://world.guns.ru/assault/as18-e.htm

There are pics on the site that show this all better.

This is the essence of it:
The original military issue AR-15 / M16 rifle (circa 1965), with no forward assist and with the original three-prong flash hider. Both this one and the A1 had the round post front site with 6 notches for an adjustment of 1 click = 1" at 100yds.

M16A1 rifle, with the forward assist, "bird cage" flash hider and the 20 rounds magazine (1967) Both this one and the original M-16 were selective fire with full auto.


The M-16A2 has the round hand guards, a square post front site with just 4 notches that move the strike of the bullet about 3/8" per click at 25m. The A2 also encorporated a new rear sight with a much larger appiture short range sight, and the range adjustment handwheel under the rear sight. The A2 was also the first to depart from the full auto, and go with the 3-shot burst. Internally it had 2 disconnectors, one for semi and one for burst. The Burst disconnector has a second hook that rides on a ratchet assembly mounted to the right hand side of the hammer. The A2 uses the same kind of "Bird Cage" flash suppressor as the A1, except that the bottom most hole is closed. This was done to cut down on the amount of dust being thrown up when firing from a prone position. It really has nothing to do with preventing muzzle climb as there is no muzzle climb when fired from the shoulder. The A2 also incorporated a longer stock, about 1" longer, with a storage compartment for cleaning equipment. Lastly, it incorporated a heavy barrel. The outside diameter of the barrel from the muzzle back to just behind the A-Frame, is larger and heavyer than the earlier versions, and the rifleing changed from a 1:6 to a 1:7 twist to be used with the heavier Green Tip M-855 ball ammo, and is accurate to 600m for a point target as opposed to the older version's 500m accuracy.

The A3 was the first to go with a Flat Top which allows optical sights and scopes to be attached at the same level as the rear sight. There is also a standard carrying handle with the A2 style rear sight available that can attatch to the flat top, picitinny rail.

Finally the M-4 with the 6 position tele-stock is technically a Carbine and evolved along a completely different line. You can read more about that here:
http://catm.com/cgi-bin/yabb2/YaBB.pl?num=1085979171
This is the unofficial website/message board for USAF Weapons Instructors. This thread was answered by Captain Richards who's done a lot of research on the carbines.

Basicaly though, the M-4 is found in 2 forms, A2 style with a fixed A2 style Carrying handle and rear sight, and A3 style with the flat top rail and the detatchable rear sight. The narrow band in the barrel of an M-4 is to allow the attachment of the Colt M-203 40mm Grenade Launcher and is the same diameter in that band as the barrel has just under the front of the hand guards.

One other note. Osprey, I don't mean to bag on ya' brother, and forgive an ORF if I'm missunderstanding you, but those feed ramps you mentioned under the M-4, have been there since day one. Even in the old original AR-10, the predesessor to the M-16, those bottom two locking lug slots have been milled larger than the rest for that very reason.

[Colorado Osprey]

If anybody else wants to add more feel free....I will not be offended.

I am by no means the answer to all or even remotely always correct.

[PsychoI3oy]

Brass deflectors are in there somewhere, too. I think introduced on the M16-A1, right?

[Ice Pirate]

Yep Phyc, you're right, I'd forgotten about that piramyd shapped brass deflector just aft of the ejection port. That was first seen on the A1. Good eyes lad!

[delta6]

There were about 40 production changes from the A1 to the A2, here are the most notable:

1. Flash supressor similar to the A1, except bottom 2 slots were eliminated. Also in the manuals the term muzzle break was included in description with the term flash suppressor.

2. Barrel contour is changed, heavier from the front sight base forward) and twist is changed to 1/7.

3. Front sight is a square post and has only 4 adjustment slots.

4. Handguards are round.

5. Handguard cap is round.

6. Delta ring is tapered.

7. Front upper receiver lug has been reinforced and case deflector is added.

8. New redesigned rear sight with a different aperature.

9. Forward assist button is round.

10. Pistol grip is reconfigured.

11. Selector is now safe, semi, burst.

12. Some of the fire control parts were changed to facilitate the burst only option (trigger, hammer, disconnector,some springs, etc.).

12. Butt stock is 5/8" longer as is the lower receiver extension.

13. Squared and checkered butt plate.

14. Two areas reinforced on the lower receiver: a reinforcing rib at the top rear of the receiver and a small amount of material added to the lugs at the front take down pin holes.

15. A whole host of other changes that are somewhat subtle, material composition, heat shield construction and redesigned butt stock storage door are just a few.

Hope this helps.
delta6

[Caliber357]

Well, that about answered any questions I'd be versed enough to think of! I'm just now starting to get my interest piqued in picking up a genuine AR - and finding out about the .50 BMG uppers to be had, just basically sealed the whole deal. Just out of idle curiosity - has anybody heard of a .408 Cheytac upper? I haven't, but I would imagine it would make for a handly lil' blue-helmet popper.

Anyway, thanks again for all the details and info guys - you certainly know your stuff. I appreciate your time!