identify magazines

[c_corrick]

i have 4 m1 carbine magazines, and they have stamps on them that identify who they were made by, i have the following, IA, U, KI, and BW, can anyone tell me who they were made by, and how many manufactures there are???

[jimb2]

U = Union Hardware (generic)
IA = Autoayre for Inland
KI = Keeler Brass for Inland
BW = Bridgport Metal Goods for Winchester
How many manufacturers? Probably around 65 or so with anywhere from 1-4 models per manufacturer. I know of over 145 different variations....

[remchuck]

ia ai the same as ia?

[jimb2]

Yes. Autoayer marked mags several different ways. A.I., I.A., IA underlined, AI underlined, and AI with lines both top and bottom. There may be some other ways as well. And they made all 5 types of base plates as well. Lots of variations just for the Inland mags.

[dockie]

How about M2, this is just the marking that i saw in my 30 rounder magazine

[jimb2]

The mag marked only M2 is a commercial mag. The USGI ones with an M2 marking are marked AI over M2 and KI over M2.

[dockie]

Ok thanks, now i knew the difference and wont get rob, telling me that kind of magazine is original GI, never thought that 30 rounders are all made in Asia, but efficient functioning of any kind of magazine depends on the owner and how they maintain it

[jimb2]

If it works well that is generally correct. But keep in mind that some mags are made with thinner steel than others. The constant pounding that they recieve can cause the feed lips to bend and separate regardless of how well they are cared for. Springs can also weaken over time and use. Either of these can eventually lead to a magazine no longer functioning properly. USGI mags are better made and usually last much longer. Another area of the mag that can go bad is the tabs that lock into the mag catch. Many commercial mags don't have that area properly hardened. Those tabs may shear off. USGI mags had to be properly heat treated to prevent that from happening.