M1 carbine reliability

[XBT]

I went shooting the other day, and on the third shot broke a locking lug completely off the bolt of my carbine. It’s an early Universal, one of the better ones with mostly G.I. parts. It hasn’t been shot much; I don’t know why it broke.

http://i2.photobucket.com/albums/y9/retiredBT/Bolt2.jpg

Weird….. Oh well, a new bolt is on the way.

Speaking of carbines, I’ve owned a few, both clones and G.I., and shot several more. I’ve never had one that was completely reliable. Despite my best efforts at tinkering, the best reliability I can get is an average of two jams per hundred rounds. If they weren’t such neat little guns I’d quit messing with them. I think the problem might be related to the loose fit of the magazine into the receiver, but I’m not at all sure.

Any thoughts on this?

Jim

[Scrounger]

I went shooting the other day, and on the third shot broke a locking lug completely off the bolt of my carbine. It’s an early Universal, one of the better ones with mostly G.I. parts. It hasn’t been shot much; I don’t know why it broke.

http://i2.photobucket.com/albums/y9/retiredBT/Bolt2.jpg

Weird….. Oh well, a new bolt is on the way.

Speaking of carbines, I’ve owned a few, both clones and G.I., and shot several more. I’ve never had one that was completely reliable. Despite my best efforts at tinkering, the best reliability I can get is an average of two jams per hundred rounds. If they weren’t such neat little guns I’d quit messing with them. I think the problem might be related to the loose fit of the magazine into the receiver, but I’m not at all sure.

Any thoughts on this?

Jim

I'd be tempted to try glass bedding the magazine well so the magazines had a more consistent, better, fit. It can be done without permanently attaching that one magazine in place.

[carpetman]

It unexplainably broke---maybe somebody has been tinkering with it?

[Scrounger]

It unexplainably broke---maybe somebody has been tinkering with it?


Blame it on the cats.

[waksupi]

My X wife had an M1 carbine. We shot it quite a bit, with no function problems at all. Sure do miss that little rifle.

[Linstrum]

Hi, XBT. Judging from both the situation and the looks of the broken steel surface it is a heat treat problem. You can do a simple test yourself. Take a file that is new or hasn't had much use, say a 6" or 8" mill-cut or fine-cut, and try filing on an edge or corner along the break with a medium amount of hand pressure. If the file just skids like it was greased without making hardly any cut and just makes a "zing" noise, then the steel is up around 510-Brinell, or more, and WAY too hard. Bolt lugs are supposed to give a little when over-stressed and not crack off like that, which is why I think it is a heat treat problem. The other alternative is that there was a flaw in the steel forging. A major, MAJOR problem with forged steel is getting a slag inclusion incorporated into the forging, which becomes a "point of abscission" or parting-line and a crack will propagate from that place if the weak point is under shock load stress. Forged connecting rods have this problem and in expensive engines (like aircraft engines) the forgings are X-rayed to look for flaws. Probably what happened was that your bolt was heated and quenched to full hardness, but got left out of the tempering bath. On a lot of bolts, especially on M1 Garand, M1 carbine, and M14 bolts, you will always see a little dimple pressed into the steel that looks like it was made by a little tiny ball bearing ball. This is where the steel was tested for its hardness. Just like testing boolits for hardness with a little ball, the hardness testing machine uses a tungsten carbide ball with a known pressure on it and the depth it presses into the steel is translated into Brinell hardness. Rockwell testers use a little diamond point sharpened to a 60° angle cone instead of a ball but the principle is the same.

I have a 1942 .30 carbine made by Underwood Typewriter that was re-arsenaled in 1952 that I bought in 1965 from Sears for $35 and I have never had one single failure to function with it in 40 years. I used G.I. surplus ammo until that dried up and my reloads are with the Lyman #313226 93-grain round nose sized to 0.308" with 2400 and the Lee .309-113F with a medium burning WC820.

[XBT]

I got this carbine in a trade at a gun show over twenty years ago, and have probably only shot two or three thousand rounds through it since I got it. I never looked closely at the bolt until after it broke, but I think I would have noticed a small crack or something similar. I think it failed “all at once�.

I did the file test as suggested by Linstrum and it doesn’t seem to be overly hard. The file would “bite� and I made a shallow cut in only one pass. It looks like it may have been a flaw in the metal. I did find a small dimple in the bolt where it was tested for hardness.

Only about an hour after my first post the mailman brought my new bolt. After I installed the bolt I tinkered the trigger group some to tighten its fit on the receiver. That helped the loose magazine problem and when I test fired the gun, it went over one hundred rounds with no problems.

Compared to the current crop of pistol caliber carbines, (Beretta, Hi-Point, Ruger and others) the M1 carbine really shines. It has decent ballistics and looks so much better. My grandson brought out his Hi-Point 9MM carbine the other day and though it is reliable and accurate, it’s so ugly that you can’t look directly at it or it will hurt your eyes.

I have done some testing with cast loads in this gun and it shoots them fine. I intend to switch to cast only as soon as I use up my existing stock of “other� boolits.

Thanks to all and especially to Linstrum for the information, Jim

[Scrounger]

Compared to the current crop of pistol caliber carbines, (Beretta, Hi-Point, Ruger and others) the M1 carbine really shines. It has decent ballistics and looks so much better. My grandson brought out his Hi-Point 9MM carbine the other day and though it is reliable and accurate, it’s so ugly that you can’t look directly at it or it will hurt your eyes.

AMEN

[StarMetal]

Art

You're right (everyone hear that, Arts right) those Hi Points are gawful ugly. The just did a write up bout one in a gunrag and it got raving reviews. Chewed throught alot of ammo which even a hiccup. Wonder if Shaw makes their barrels? har har har

Joe

[NVcurmudgeon]

In my Navy days in the middle fifties, the standard weapon for in-port watches on deck was the M1 Carbine. Occasionally we would shoot them at floating trash, or in the case of one deadeye officer, clay targets from a hand trap. I never saw any malfunction despite poor, or no, maintenance. I have shot several XGI examples since, and they just don't ever burp. Accuracy is a lot better than an issue 1911A1, which Carbines were intended to replace.

[Pop_No_Kick]

Just checked my Universal M1 (pawn shop) for stress cracks on the lugs,, so far so good.. thax's for the heads up.
also glad your OK.... noth'n beats catch'n a bgolt in the face...

Chuck

[Frank46]

XBT, I seem to remember that the flat bolts were the early ones and when the round bolts were introduced for the M2 carbine the older bolts were supposed to be no longer used in either the M1 or M2 carbines. Knhnhausen states in his carbine manual that bolt bodies are off spec in regards to heat treatment too soft that were used in commercial carbines. Good thing that you were not damaged. Frank

[Buckshot]

............I suppose it could be chalked up to the fact too, that over 6 million complete carbines were built and possibly 3 times that many USGI spare bolts. Something somewhere is going to happen. A member here, VP was shooting his at the range one time several years ago and the gas piston nut broke. Pretty serious if you were in a firefight, but no big otherwise.

I like to keep what I consider consumable parts on hand for all my non-commercial rifles. These don't include bolts :-) but are such things as springs, sears, extractors, ejectors and firing pinss and such like.

I've only owned one M1 carbine and that was one produced by Iver Johnson, which was fully faithfull to the GI one. Never had a moments problem with it and it was sure a fun gun to shoot. I ended up selling it for some unknown reason. a few years later when the first big lend lease re-importaion of them took place you could pick them up all day long for $125.

A buddy bought a couple of'em and needing something to do, had our gunsmith accurize the action on one. Meaning both lugs bore evenly on the action with the bolt 'on' axis with the barrel, and the barrel faced square with the reciever and rechambered. Stuff reserved for high powered rifles.

One of the major problems with accuracy is the way the barreled action is retained in the stock. All this work he did himself. He bedded the action lug into the stock and fitted the rear of the action to it. The stock was inlet with the barrel bedded at the front and the front band was fit so the barrel didn't bind in it. The action was bedded using much the same things used on the Garand of which the carbine is a recognizeable relative.

He was able to turn it into a reliable deliberate 100 yard varmint rig which would pot 5 rounds into an inch and sometimes better. That was good consistant accuracy with all GI parts, just tuned as they couldn't do in wartime production.

..............Buckshot