The Complete Guide To Colt M-16 Models: Part I

Dan Shea — Sun, 01 Feb 1998 23:22:00 +0000

By Dan Shea

XAR 1501: The Prototype

The M16 series of rifles has had much written about them. How to fix them, how to shoot them, the history and development- is all very well covered. What has been missing is a basic guide to the models, and how to identify them properly. SAR has embarked on this mission, and the body of knowledge just keeps growing, and growing….. At present there are 4 parts to the series, the first three are devoted to the actual models, and the fourth is composed of a comparison of the distinguishing features of each major characteristic change. We hope you enjoy this series, and can utilize this guide in your understanding of what is “correct” for each model. We are looking for input, and for photos of markings and models that we are missing. In particular, we need the markings from an XM16E1, XM177E1 and 2, and the GAU-5A.

It is our sincere hope that this photographic essay will help people to identify what they have, and what should or should not be on it for features. One point that should be remembered is that many of these models were transitional in nature, and two different flash hiders might have been correct, or some other dual characteristic. It is almost impossible to sort this out- someone will always come forward later and show an original model that is “Different” from what the previous body of knowledge has ascertained. It is in this spirit of investigation SAR offers this ID Guide to the Colt Models. Please address any new info you may have to us at SAR, and we will try to incorporate it into the future parts of this four part series. (Four parts – so far!)

Colt 601: Model “01”

Armalite First AR-15’s: The first AR-15 production was 10 rifles done by Armalite for the US Military for testing. There are only a few that are still in the original configuration. Number 000001 is original except for the flash hider. Charging handle in the carrying handle, fibreglass buttstock, and one piece forend. The 25 round steel magazine was also unique to these rifles. Safe is in the center position.

Colt 601: Model “01”. The “01” is the original Colt / Armalite AR-15 rifle put into service in the early 1960ís. The ìWaffleî type magazine is correct for this model, but other magazines do work. Charging handle to the rear, 3 prong ìDuckbillî flash hider, 2 piece triangular forend and chrome bolt carrier. Safe is now ìLever to the rearî. No foreword assist.

Colt 602: Model “02”. The “02” is the initial version of the M16 rifle. Some were marked with the US property marking. These were referred to as the “XM16”, with the “X” designating ìExperimentalî. New style charging handle, 2nd style 3 prong open flash hider, 20 round steel magazine, no forward assist, chrome bolt carrier.

Colt 603: Army – M16A1. In 1967 the military dropped the “X” notation, as this was no longer an experimental model. The “603” is the common form that the M16A1 project took for the duration of the Vietnam war’s buildup and it was in use until the M16A2 project was completed. These are still in many armories today. The 603 marks the appearance of the “birdcage” (3rd model) flash hider. Forward assist, chrome bolt carrier, trap door buttstock.”

Colt 604: Air Force – M16. Air Force contract M16’s were the model ì04î, and the designation was in the serial number range -starting with ì04î. The Air Force did NOT want a forward assist on their M16ís, and initially there were bolt carriers made that did not have the serrations. Eventually, this separate carrier was dropped in the interest of standardization of parts, so either carrier can be correct. 3 prong flash hider, no forward assist, chrome bolt carrier, trap door buttstock.

Colt 605A: CAR-15 Carbine. These first CAR-15’s were made for production but never made it to general use. The shortened barrel and standard forearm made the CAR-15 into a fairly small package, but Colt had other ideas on the drawing board that were of more interest as ìShortiesî. 15î barrel, 3 prong flash hider, full fixed buttstock, forward assist, chrome bolt carrier.

Colt 605B: O5-B. This is an “Air Force” version of the 605A, in that there was no forward assist. The burst mechanism makes itís appearance in the O5B, as a four position selector giving 3 shot bursts at the bottom position. No bayonet lug. 15″ barrel, 3 prong flash hider, full fixed buttstock, no forward assist, chrome bolt carrier, burst mechanism. No bayonet lug.

Colt 606: Heavy Barrel. The 606 is the first appearance of a true heavy barrel, and it is the H-Bar version of the Model 604. The 606A had the forward assist, and was the H-Bar version of the Model 603. 20″ heavy barrel, 3 prong flash hider, full fixed buttstock, no forward assist, chrome bolt carrier

Colt 606B: O6-B. The 606-B is a true heavy barrel, that utilized a bipod. The “B” designated ìBurstî with the burst feature at the bottom position. Some of the 606 and 606A models could also be correct with the bipod assembly. 20″ heavy barrel, 3 prong flash hider, bipod, full fixed buttstock, forward assist, chrome bolt carrier,

Colt 607: 07. The model 607 is the first M16 submachine gun. The triangular sliding buttstock is unusual, and only appeared on this model. Colt has now cut down the forend to adapt to a shortened barrel, and the ìSuppressorî, which must be legally registered as a silencer, is actually a device to increase the back pressure to make the system function. Several of the “07”s” were sent to Vietnam, and there is at least one that saw serious combat- you can tell because of the 7.62 x 39mm bullet hole in the forend. Regular bolt carrier, 10″ barrel, suppressor, sliding buttstock, small handguards, no forward assist, no bayonet lug. Short pistol grip.

Colt 608: Survival Rifle. The Air Force Survival Rifle had an unusual fixed stock, and the whole purpose was to make an effective two piece carbine that would come apart at the takedown pins and be readily stowable. Regular bolt carrier, 10″ barrel, suppressor, fixed buttstock, round handguard, no forward assist, no bayonet lug. Short pistol grip.

Colt 609: The “Commando”. This is the original ìXM177î model of the M16 submachine gun. Original 609’s are marked ìCommandoî as in the illustration, and they are also U.S. Property Marked. Colt went back to the full pistol grip on the Commando. The “E1” Army version had the forward assist, and the straight XM177 did not- this was the Air Force model. 10′ barrel, short round forend, flash hider features added to the suppressor, sliding metal buttstock, forward assist, standard bolt carrier, full pistol grip, no bayonet lug

Colt 610B: 610B. The 610B toolroom guns were four position three shot burst submachine guns. The 610 series had no forward assist, and the regular 610 did not have a burst mechanism. 10î barrel, short round forend, flash hider features added to the suppressor, sliding metal buttstock, no forward assist, chrome bolt carrier, full pistol grip, no bayonet lug, experimental slip ring

SAR would like to thank Mr. Reed Knight Jr. for his help in this series

This article first appeared in Small Arms Review V1N5 (February 1998)

The Complete Guide To Colt M-16 Models: Part I – Small Arms Review

The Complete Guide To Colt M-16 Models: Part I