This thread is intended to be a guide and learning process about the evolution of the AR-15 Magazine. The resources from which I have gathered information include years of reading this forum, The Black Rifle 1, Vickers Guide AR-15 Volume 1, and A Collectors Guide To The Colt AR-15 SP1 Sporter Rifle. I will do my best to summarize these books without infringing on copywrite. I highly encourage any serious students, retro AR enthusiasts, and collectors to purchase these books. I also hope this thread will lead to more photos and information being gathered from the members of our community. Secondly I am going to include photo's I have saved over the years that have been posted here in the forum, but I do not have credit as to who took the photo's unless they are mine. If you would like credit that it was your photo please let me know. Also many of the photo's I've collected and posted in this thread are not of the greatest quality. If you have examples you can post with better photo's that you wouldn't mind me using in the thread, I would greatly appreciate it.

Prototype Magazines:
The magazines developed by Armalite for the AR-15 prototypes were a 25 round straight body aluminum magazine. The prototype magazines did not have an overtravel stop that protruded from the left side which is why the lower receivers on prototype rifles were smooth sided on the left side. The Vickers Guide book speculates based on various reports that the magazine size was dropped to 20 rounds on production AR-15's due to the possibilities of weight savings, ammunition savings, and Army tests indicated the magazines were less reliable when loaded to full capacity. It is unknown how many prototype magazines were produced, but TBR1 states 10 rifles and 100 magazines were delivered to Ft. Benning for testing in 1958.











The 20 Round Magazine:


Steel Waffle Magazines:
Colt redesigned the magazine for the AR-15 (Colt 601 at this point) based on the proven design of the waffle magazines that were in use with the AR-10 at the time. Three variations of waffle magazine exist based on the follower. These magazines proved to be less reliable than desired and prone to corrosion. There are four known variations in the design of the waffle magazine. We know there exists a cast follower version with the letter S included, a cast version without any letters, a stamped follower with locking tabs on the floorplate, and a stamped follower of a different design without locking tabs on the floorplate.










First Aluminum 20 Round Magazines:
According to the Vickers Guide, as early as 1959 Universal Industries was contracted to develop an aluminum 20 round magazine. The early production process was labor intensive with many steps and very tight tolerances to produce reliable magazines. The early magazines were stamped, folded, and welded on the spine. Before the patent and licensing rights were finalized by Colt's, the floorplates retained the Amalite name.

Waffle mag and Armalite marked 20 round aluminum mag for comparison:




(Waffle mag on top, Aluminum on bottom)

There also has been a version of this magazine found that were black anodized with the same cast follower as the steel waffle magazines




After Colt acquired rights to the AR-15, magazines were marked with Colt name and pony logo. Early floorplates are generally silver in color and get darker through the 1960's.



Some magazines of this era feature a circle with a 1 inside on the left side towards the bottom of the magazine body. Three variations exist, a right side up 1, an upside down 1, and a circle without a 1. There is some speculation that the "Circle 1" magazines were originally made for the Piggyback system, and when that idea never came to fruition the magazines were shipped with commercial rifles . Many early SP-1's were shipped with Circle 1 magazines, up through 1966 according to the SP-1 Book. Early SP-1 rifles were also usually shipped with magazines that had a round white sticker on the bottom of one side of the magazine body.

This is a very good thread on circle 1 magazines with good photos: M16Indiana Thread on Circle 1 and SP1 magazines




Universal President Edward Ardolino patented a magazine coupling system were two floorplates could be pushed together at the base to form a "piggyback" system. Prototypes of the system were made but the idea did not reach large scale production. M16Indiana has found two versions of the piggyback system, one with circle 1 magazines and one without.





By 1966 Universal had developed a method of production that increased quality and speed of production. There were no markings on the magazine bodies.



At some point Universal Industries began stamping magazine bodies with a stamping that reads UI (Universal Industries) when read vertical, and CH (Colt Hartford) when read horizontal. Magazines with these bodies were used on both magazines made with Colt and Universal floorplates.





In 1969 Colt switched from marking rifles and magazines from ".223" to "5.56." The earliest "5.56" 20 round magazines had aluminum followers, but they were switched to black plastic soon after production started. Magazines marked: "Colt AR-15 Cal. 5.56MM Colt's Firearms Division" with plastic followers continued from this time into the 1980's.




In December 1969 a contract was awarded to Adventureline for 2.4 million magazines.








Universal also was supplying magazines under their own name. This is a (new?) magazine I took out of packaging to photograph.







The 30 Round Magazine:


The "Constant Curve" 30 round magazine:
Colt developed a 30 round magazine in 1965 to go along with their carbines to be entered into the SAWS trials. In January 1966 the Combat Developments Command required that each rifleman be equipped with five 30 round magazines. The original plan was for all new rifles shipped in  1966 be shipped with 30 round magazines. Soon after problems arose with the magazine not fitting in all lower receivers that had been made up until that time, or at least not fitting in the lowers at the right angle to function 100% of the time. Colt started redesigning the magazine in early 1966. There are some "constant curve" magazine in the hands of collectors, but they are extremely rare.

Photos of both a constant curve and "62667" type magazine together:







The first successful production 30 Round magazine:
Colt had the 30 round magazine redesigned and submitted for testing as early as April 1966. They have the curvature profile we are still familiar with today, where a straight portion extends out the lower receiver and then curves forward. In June 1966 Colt applied for a patent on the design, which also featured other improvements from the first generation of 30 round magazine including; the follower was made from a synthetic material as opposed to stamped steel, the feed lips were slightly altered, and the aluminum was slightly thicker. Colt was awarded a government contract for these magazines in May 1969. These magazines had the Colt part number for the body stamped on the right side (62667) and the followers were emerald green with the follower part number painted in white (62665A) Eventually the numbers were dropped from the production process, followers were switched to black nylon.





OKAY Magazines

In 1968 Edward Okay, the magazine production manager at Universal Industries; bought a manufacturing business and renamed it after himself. His new business started making 20 round magazines for Colt and was given a government contract for 30 round magazines in December 1973. Okay and Colt had a close relationship in the manufacture of AR15 magazines for decades. They were granted CAGE Code 33710 in November 1974. Magazines with this CAGE code would be produced with both Colt and Okay branded magazine bodies and floorplates.




Non-Colt 30 Round Magazines:

Adventureline 30 round magazine with "87" date code stamped on the inside, along with 010 and K10 on the opposite side. The meanings of those stampings are unknown to me.




Adventureline was bought out by Parsons, which was later bought by Center Industries. CAGE Code 6P199 was issued March 1978


FN America was granded CAGE Code 3S679 in October 1979


CAGE Code 30389 was issued in November 1974

There’s a post in a thread where I speculated on the number of 25 round mags that were made but it’ll be impossible to find now. I believe I said it would be more like 100-300 - the reason being the fact that each AR-15 tested was delivered with 10 magazines each. With #27 being the highest known serial, that could be up to 270. And I'm not convinced that #27 was the last rifle either. It’s possible only the first 10 rifles were delivered with 10 mags, but considering the numerous iterations of testing for the same rifles at different installations, I don't think 1 set of 10 would have sufficed.

I doubt we'll ever know, but thats sound logic. Thanks for sharing.

This should be a sticky. I know I'm going to request it. My requests sent to both moderators. If anyone else thinks it should be a sticky or prevented from archiving, may want to shoot them a PM.


Nice job kid.

Universal Industries is missing, and I think they date from 1969 before Adventure Line, which I thought was post 1971.

Floorplate:

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Front with the UI logo and follower:

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And side view:

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Im not an expert, just a guy thats read a few books so Im hoping more people chime in. Im also not really sure what the best way to organize the OP is, but I went with Chronologically by type.

The Vickers Guide book basically says that UI was contracted by Colt to make all the aluminum 20 round mags up until the Adventureline contract is how I read it.

UI was a long time sub to Colt, but I think also got a direct contract with the military sometime 1967 / 1968.

Do to the style of the UI logo marking, , turn it 90 degrees it's CH. (Colt Hartford)

Biggerhammer Forum and TROYS MAG FAQS both have good info regarding mags.

Added some UI and Adventureline mags ^

Place holder an Adventure line 30rd mags I have and some of its friends.

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Ask and I shall receive, awesome job with this thread!

Thanks for posting, do they have date codes inside the magazine?

Thanks

Well done!  This os one of the most informative threads i have ever read on any forum!

Outstanding!
Insert the clapping Orson Wells gif here.
Very nice.

I pulled them apart today and did not find any date codes.   Happy to provide any other pics / info if it is useful.   The Center industries mag is 10/91 on the outside.

Thanks for checking and for your contribution! I rotated and added your photos to the OP.

According to the Vickers Guide, Okay started supplying mags in the 1970's. Does anyone here have an early Okay mag?

Here is one of my “piggy-back” mag sets.  This one has circle 1 mags, and the other had plain mags

I have another variety of waffle mag with sheet metal follower, and it does have the locking tabs on the floor plate

I have found that there are TWO distinct varieties of the Colt/Armalite aluminum magazines. First is the standard variety as shown upthread with gold or silver anodizing, and standard aluminum follower.  Second, is the black anodized variety, and every one that I have found (about a dozen) has the same follower as the waffle magazine.  Pure CONJECTURE on my part, but I wonder if the black anodized ones were designed to be issued black, with no silver paint on them, and they later painted them with the standard silver paint.  My THEORY is that the black anodized mags with waffle mag followers were 1st model Colt/Armalite aluminum mags, and the gold and silver anodized mags with standard 20 round mag followers were the 2nd, later model.  Here are four of my black anodized Colt/Armalite mags with waffle followers, with a standard gold one above them



Here are the followers of the four black mags on the left, with the standard follower found in a gold mag on the right


Floorplates appear to be the same on both varieties

The prototype magazine shown upthread belongs to me.  It came with an interesting story - it was found in a surplus M-16 magazine pouch in a container of M16 mag pouches sold off in a government auction in the 80’s or 90’s.  How it got there is anyone’s guess.  The unique thing about this magazine is that it was professionally modified to fit in a prototype rifle, OR ANY M-16 variant from the 601 on. A normal 25 round prototype magazine will not fit and function in ANY M16, and the standard 20 and 30 round M16 magazines will not fit and function in a prototype rifle.

@M16indiana Thank you for sharing, I was hoping you would contribute! Im going to add your photo's to the original post.

Thank you for the extra information on the 4th type of waffle mag, the second type Armalite aluminum mag (I think your logic with the followers is sound), and the additional info on the prototype magazine.

Added OKAY and Center Industries to the OP.

It seems like the CAGE code system was implemented in November 1974 and any manufacturer that was already doing business prior to that time shows a "Nov 1974" CAGE code issue date.

https://cage.dla.mil/search

Good info.

I will try to check, unfortunately a few years ago, I had a friend on here sell my many of my old magazines to the ones here behind E. lines.  So you all could have more than what ever it was.