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M1/M2 carbine magazine catch question.
Marv
Member Posts: 76 ✭✭
I've got a M1 carbine made by I.B.M. It was most likely started as an M2 due to the round bolt and "eared" magazine catch and converted to semi-auto configuration when it was imported back in from Korea in the late 80's by Exel of Gardenia, MA. The magazines have alway had side to side play or wobble when seated. 15 rounders worked and fed fine but the 30 rounders were iffy. At the range the other day I had several FTF's with a 15 rounder. I discovered one of the spot welded "tits" or nubs on the back of the magazine had popped off and was causing the immediate problem but prompted a review of the "wobble" problem and why it doesn't like 30 rounders.
The thing that I observed is that the "eared" piece of the magazine catch does not go in far enough to touch the side of the magazine or to lock under the projection on the side of the 30 round magazines. The ear actually sticks out farther than the nub and leads me to believe something ain't right. I've read the M-2 catches were backwards compatible on the M1 and M1A1 but do they require fitting? If so, how would that be done? Also, would the housing have needed to have been changed or just the selector, sear, hammer, etc. to make it a semi-auto? Any info or help pointing me in the right direction would help. Thanks in advance.
The thing that I observed is that the "eared" piece of the magazine catch does not go in far enough to touch the side of the magazine or to lock under the projection on the side of the 30 round magazines. The ear actually sticks out farther than the nub and leads me to believe something ain't right. I've read the M-2 catches were backwards compatible on the M1 and M1A1 but do they require fitting? If so, how would that be done? Also, would the housing have needed to have been changed or just the selector, sear, hammer, etc. to make it a semi-auto? Any info or help pointing me in the right direction would help. Thanks in advance.
Comments
Initially, the M1 carbine was intended to have a selective-fire capability, but the decision was made to put the M1 into production without this feature. Fully automatic capability was incorporated into the design of the M2 (an improved, selective-fire version of the M1), introduced in 1944. The M2 featured the late M1 improvements to the rear sight, addition of a bayonet lug, and other minor changes.
Research into a conversion kit for selective fire began May 1944; the first kit was developed by Inland engineers, and known as the T4. Inland was awarded a contract for 500 T4 carbines in September 1944. Although the conversion was seen as satisfactory, the heavier 30-round magazine put greater strain on the magazine catch, necessitating the development of a sturdier catch. The slide, sear, and stock design also had to be modified. On fully automatic fire, the T4 model could fire about 750 rounds per minute, but generated a manageable recoil.[78]
Although some carbines were marked at the factory as M2, the only significant difference between an M1 and M2 carbine is in the fire control group. The military issued field conversion kits (T17 and T18) to convert an M1 to an M2. Legally a carbine marked M2 is always a machine gun for national firearms registry purposes.
These M2 parts including the heavier M2 stock were standardized for arsenal rebuild of M1 and M1A1 carbines.
A modified round bolt replaced the original flat top bolt to save machining steps in manufacture. Many sources erroneously refer to this round bolt as an 'M2 bolt' but it was developed as a standard part for new manufacture M1 and later M2 carbines and as a replacement part, with priority given to use on M1A1 and M2 carbines.[79] The slightly heavier round bolt did moderate the cyclic rate of the M2 on full automatic.[80
Exel bought most of the "good" Korean carbines; other importers often got carbines that had been poorly repaired & refinished by Korean Army armorers.
The only mag catch that will work with 30 round mags are stamped M. Period. You may have a problem with your trigger housing, but it is unlikely.
Most 30 round mags are commercial, not USGI. The only genuine USGI mags that I have are Seymour Products (marked SEY), & unknown maker marked K1/M2. There are counterfeits out there. Some mags marked AYP work well, some don't.
If you want your carbine to function properly every time, use only USGI 15 round mags, readily available & reasonably prices.
Neal
http://www.bavarianm1carbines.com/index.html
I have one 15 rounder that won't work in any of them. Not sure who made it but it's out of spec. It won't engage deeply enough for the rounds to feed out, the bolt always overrides it.
I've never had an M marked mag catch and never had an issue with a 30 rounder. Huh.
This all said, I have read this thread with interest, hoping to work out some of my own wobble issues. What I did personally was to use a small punch to ever so slightly peen the catch with a few dimples. Seemed to increase the surface area and tighten it up, but be aware, it could also ruin the part... just an idea to try since you have a new one on the way.