AR 15/10-M16-M4

[LAVSCOUT]

The M-16 A2 came with either full auto or 3 round burst, the A2 designation actually referred to the sights and hand guard and other minor changes and didn’t dictate the trigger group. The A3 simply added the removable carry handle and again was delivered with either full auto or three shot burst. The A4 added the railed handguard and the sights were changed from 8/3 to 6/3. Although I have not seen anything other than 3 shot variations I would assume that they (the A4) are made in full auto as well.

 

[Bartholomew Roberts]

The M-16 A2 came with either full auto or 3 round burst, the A2 designation actually referred to the sights and hand guard and other minor changes and didn’t dictate the trigger group.

This is incorrect. Mumbles45's first post on this subject is correct. The A2 is a 3rd burst and incorporates the USMC upgrades to the M16A1. The A3 incorporates the same upgrades; but has a full-auto trigger group.

The A4 added the railed handguard and the sights were changed from 8/3 to 6/3.

The A4 is the flattop version of the A2 and usually incorporates a Knight's railed handguard (note that whether a weapon has a railed handguard doesn't change its nomenclature - an M4 with double-heat shield handguards is still an M4 when you put a Knight's RAS on it). Also, ANY USGI detachable carry handle will be marked 6/3. It is impossible to have an 8/3 marked detachable carry handle because the interface to attach it to the 1913 rail means that you cannot have a screw long enough for the 7/8 elevation on a detachable carry handle.