Looking for a non obvious reason for the curve design of a 30 round magazine ended up stumbling in this older post.

(Posted by Augee) "...Armalite originally designed a twenty five round capacity straight magazine, but it was discontinued. "

And this related info from the "Technical Notes on Small Arms Design 1968" under the "Magazine Design" section.



From: http://www.forgottenweapons.com/small-arms-design-literature/



Eugene Stoner straight magazine illustration

A 1969 Patent for a rectilinear magazine.



FIG. I is a side elevation of a magazine in accordance with the invention;

FIG. 2 is a cross section on the line IIII of FIG. 1;

FIG. 3 is a fragmentary side elevation of the spring in its free state;

FIG. 4 is a schematic view showing the different positions of the follower at different conditions ofloading.

In this Patent,the idea is not to have the ammo stacked vertically inside but so that the magazine fabrication can be made cheaper.

A 1967 Patent by Robert Fremont from Colt for a "Firearm box magazine with straight end and intermediate arcuate portions".



FIG. 1 is a side elevation, partly broken away, of a magazine embodying the present invention;

FIG. 2 is a front elevation, partly broken away, of the magazine illustrated in FIG. 1 and showing several cartridges in place therein;

FIG. 3 is a perspective view of the lip and magazine housing segment and follower of the magazine illustrated in FIG. 1.

Is this the patent for the magazine still in use today?

Robert Fremont,is this the same Robert Fremont that,with Jim Sullivan,helped to design the AR-15 at ArmaLite?

In this 1977 Patent for a plastic magazine,one can see the tumbling of the feed plate inside.

One variat of the AR-10 used a curved magazine with the  7.62x39mm caliber.



7.62x39mm caliber variant

Hey that's me holding a Hollywood.
This was taken at the attick of the Legermuseum in Delft, 25 years ago.
The 7.62x39 was a project for Norway, Finland or Sweden. (not sure wich one)
Only a few were made and this one blew up when they shot it to show it to a collector who wanted to buy it.
If you look at the internet page of the legermuseum now, they show a full lenght rifle as the 7.62x39 but it's not.

That was a fun day at the attick.
At that time they had more than 30 different types of AR10 rifles.
Every one of them had a small modification, different from the other.

R.I.P Kick Koster

Hi,thank you for the feedback ar10stef.

Due to the tendency that the case as to tilt tip down (and the magazine inner design works) that the AR-10A (last AR-10) had the magazine receiver section and magazine placed with a slight tilt,to compensate for this natural case angle so feed could be made better?



As this AR-10A was done based on the AR-15,can this mean that the AR-15 was to evolve,as this case angle tilt was also to be found in the AR-15 ammo?

Wy does the West,apart from the Austrians/Swiss/Germans,use metal magazines as the Soviet Union changed from metal to plastic in 1974 with the AR-74,did the Soviet Union changed from metal to plastic for the same reason the U.S. almost changed the  one cent coin to Bakelite?

"The thermosetting phenolic resin was at one point considered for the manufacture of coins, due to a shortage of traditional material; in 1943, Bakelite and other non-metal materials were tested for usage for the one cent coin in the US before the Mint settled on zinc-coated steel."

The Spanish Cetme also uses a curve magazine,this was later changed in the German G3 for a staight magazine.