M1 Carbine Broken Bolt

[Gary D. Funderburg]

I have a comment on the broken bolt.
The problem is caused by a bad recoil spring and or poor lubrication. The carbine will fire out of battery. If you look at the front bottom of receiver there will be a white line on receiver and a line on the back of bolt where the bolt is hitting the receiver. What happens when weapon is fired is the slide hits receiver and recoil spring does not have enough power to get the bolt back in battery and it recoils with no hesitation, cracks a bolt or jerks the ear completely off. I have had both happen. " But I am very careful to clean and oil my Carbine" I hear that all the time. Carbine runs on Grease not oil. Good rule of thumb is if it rotates oil it, if it slides Grease it. For those of you that thinks I am wrong? Take your favorite carbine out to the range load it up, pull the slide back about one half inch and fire it. Anyone wants to tell me how wrong I am email me at garys615@aol.com

[George in NH]

If memory serves me correctly (I am at work and my FM's are at home) the Carbine Field Manual describes "oil" for treating the moving parts of the carbine. I have been using "Slip 2000" on my carbine and it seems to stay where I apply it. George in NH

[Litt'le Lee]

if you read futher it describes using grease for parts that wear heavy as also 3 or 4 oils including motor oil--FM23-7-jan52

[Tuna]

Gary, Everything you stated is so very true but it's not the only thing that can cause bolts to let go. If a burr does develop on the receiver where the left bolt lug sits it can cause the bolt not to close properly and then cause the bolt to break when fired. This happens with a lot of the type 3 bolts letting go. But then there are type 2 bolts that also break and they have been closed when fired. The military was well aware of this problem which did lead to the type 2 bolt replacing they type 1 and later the type 3 bolt. There is a lot of stress on the bolt when a round is fired and that can cause the weakest point of the bolt to start to let go at the extractor. But again your right about a properly cleaned and lubed carbine preventing a lot of problems.