30-Round Mags for the M1

[Minnesota Joe]

Just bought a Type IV 30 round mag for my M1 Carbine (IBM) only to discover that it won't lock into the receiver. So now what? My magazine catch is a standard "M" variety -- not underlined "M". Is this simply a question of getting a different magazine catch, or do 30-round mags only fit in an M2?

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[Tired Retired]

Your non-locking problem may be caused by a number of reasons. Check the tabs on the back of the mag and see if they are worn or rusted. Also check the mag catch on your weapon and make sure than it also is not worn or is loose.

You can use the 30 rounds mags with the standard Mag catch. The M2 catch does have an added tab on the left side to assist in holding the 30 round mag in place, mostly under combat and/or auto fire conditions. I also have a standard catch and I have no prob with the mag falling out - I just don't run, jump, crawl, etc with them.

You may also want to consider the source of your mag - is it a real one or a poorly made commercial fake? I don't have the source info on mags, but alot of guys on here can tell you all about your mag.

[Minnesota Joe]

Upon learning that my mag should work, I found the problem. The locking lugs on the back of the mag were a hair too long to allow the mag catch to close. Solved the problem by giving the lugs a few quick passes with a file. Now the mag seats in the receiver perfectly.