Question about 30-round M1 carbine magazines


Jack Straw from Wichita
June 20, 2006, 05:25 PM

On a recent trip to the range, I took my Inland M1 carbine, four 15-round magazines and six 30-round mags to do some plinking and evaluate the reliability of the various mags. The 15-rounders worked fine, but if I put more than 25 rounds into the 30-rounders I got poor reliability (the bolt would remain open and would have to be closed manually; the bolt was not locking back, but was resting against the topmost round in the mag). With 25 rounds or fewer, they functioned normally. This was true with every one of the six 30-rounders. As far as I can tell, the spring tension keeps the rounds in so tight that the bolt cannot feed the next round into the chamber.

The mags themselves are marked "AYP" which I understand to be postwar Dutch or Danish manufacture (I forget which). They're supposed to be pretty good mags, and I've kept them clean and rust-free.

So my questions are: has anyone else noticed this with the 30-round AYP mags? Is there a fix that doesn't require major surgery? Thanks for any help.


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June 20, 2006, 06:02 PM
I use AYP 30 rounders. Mine are very old and slighlty discolored. I have NO problem loading 30. They have never jammed with WWB ammo. They were made by FN in Belgium for European use. The AYP should be written inscript with the Y being slightly different from the A and the P.
You might have counterfeit AYP mags. Those were excellent mags but the counterfeit (knock off) were not so hot.
I took my UltiMak, Leupie mounted 30 M1 to a carbine class with Louis Awerbuck and Ken Campbell. It worked just fine. One of the most reliable guns in that particular class. It was taught in the old pit at the Turlock, CA range (now closed). The air was filled with a very fine dust mixed with dried manure. Heat was very bad in the central valley in summer. AR platforms did not do well in the dust. Ruger 9MM carbine was great!
Both instructors were great -- Ken Campbell in now a Sheriff.

June 20, 2006, 07:03 PM
106RR: I remember you!Yes that carbine worked great. I was always told not to load more than 25 rounds in a 30 round M-2 mag - back in 64! Wsh I could find the Ruger Carbine guy, we had him in my old motorhome , he was/is a REAL player!:)

June 21, 2006, 03:05 AM
I have forgotten his name, but he borrowed the Ruger from Duane.
The shooter later fell on hard times with his health deteriorating rapidly from uncontrolled diabetes. He began losing weight and seemed to perk up a bit. I lost track of him when the Turlock range was closed. I still see Duane several times a year. We shoot IDPA at Winton on the Safety First Range.
It's located on the Bettencourt Ranch. The gas to get down there is a real burden but I manage to make it most months.
Ironically, I was recently diagnosed with Agent Orange poisoning. This causes diabetes and many different kinds of cancer. No cancer so far and the Diabetes is under control. Every time I go to the VA they apologize for the way we were treated and for the poisoning. I guess it's no worse than getting shrapnel from your own artillery!

Mike aka 106rr

June 21, 2006, 03:01 PM
Sounds like you have either rusted or dirty mags. Give them a good cleaning and see what happens.

June 21, 2006, 03:22 PM
try oiling the mags and gun with synthetic motor oil. light coat on the ammo itself helps a bit too.

Dave Markowitz
June 21, 2006, 07:09 PM
...for a few reasons:

1. The oil attracts dirt which hinders reliability, not to mention the fact that oil + dirt becomes lapping compound.

2. By oiling the cases, you can increase case head thrust against the bolt, which again hurts reliability and may cause premature wear.

3. Finally, if the oil is a good penetrant and remains on the ammo for an extended period, it can kill the primer.

Dave Rishar
June 21, 2006, 09:31 PM
Since it hasn't already been mentioned...

Some folks say that the 30 rounders never did work quite as well as the 15 rounders. Besides the usual suspects with the magazine catch upgrade and such, there is a perception -- deserved or not -- in some circles that 30's don't always function.

FWIW, about half of mine are fine. The other half, not so fine. All of my 15's work. I'm hardly an expert though. YMMV. If downloading to 25 makes them reliable, download to 25; it's certainly not going to hurt anything.

June 22, 2006, 06:11 AM
30 round mags were originally made for the M-2(full auto option) carbine-the M-1 used the 15 round mags. The longer mags can be used in the M-1's,but they are not as reliable as the 15 rounders.
I'd strip the mags, clean them out with Hoppe's #9 and a long bottle brush, dry them out.
Give them a light spray with Break Free, dry them out again, then put them back together.
Check for dings in the mag body or followers or kinks in the springs. You may need new mag springs- Try Wolf Springs.
I believe A y P mags were made in Spain.


Jack Straw from Wichita
June 28, 2006, 06:52 PM
Thanks to everyone for their suggestions. I'm going to strip the mags and clean them thoroughly and see if that improves things. If not, I'll just write myself a big note to limit the load to 25 each.


Johnny Guest
June 28, 2006, 07:05 PM
Jack, have you considered that the magazines might be fine, but your recoil spring has gotten weak? Weak recoil spring combined with a full power magazine springs might cause enough binding on the bottom of the bolt to cause what you describe.

Happily, M1 USC recoil springs are inexpensive and quite easy to install. Couldn't hurt.

Back to the earlier line of thinking, though - - Does your Inland carbine have the M2 mag latch, with the added little catch on the side to engage the third luc on the longer, heavier magazines? If not, substituting the M2 latch might hold the 30 round mags in a slightly better position.


Art Eatman
June 28, 2006, 10:52 PM
Original GI 30-round mags worked just fine from full-up. I used to "liberate" a 600-round can of ammo from the arms shack and go to the beach at Inchon and shoot seagulls. We were issued M2 Carbines. Everything functioned, whether semi- or full-auto.


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