A Couple Minor M1 Carbine Malfunctions - Help Please

Hi Everyone.

I took my newly purchased National Postal Meter M1 carbine (arenal rework with flip safety)to the range for the first time today, and I had a couple of minor issues.

First, the flip safety would occasionally drift from "fire" to "safe'. The safety switch would drop down about 30 degrees and freeze the trigger. If I flipped the safety all the way to the safe position and back to the fire position, it would clear. This happened about once every ten round magazine. I suppose if it's going to swap positions it's better to drift to safe rather than to fire.

Secondly, the slide did not catch in the open and locked position after the last round in the mag was fired. The slide doesn't seem to lock in the open position very easily when opened manually.

Your thoughts? Any help would be greatly appreciated.

BTW, what a sweet, fun little firearm! I may have found a rival to my first love, the Garand.

Thanks!

Sounds like the spring or plunger need to be changed in the safety. Not difficult to do. The bolt hold open may just be worn, they were never great to hold open the op handle. If the bolt doesn't stay back when last round is fired, you need the mag followers that are cut square for that. The 30s had those, not all the 15s did. Just a few I've seen...you can get or modify the followers to hold open though.

The outside followers are angled, the inside two cut flat.

As BAR says check the spring and end plungers. They could just be gunked up with crud.

https://www.milsurps.com/images/impo..._zpsvnvu-1.jpg

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Originally Posted by browningautorifle

Sounds like the spring or plunger need to be changed in the safety. Not difficult to do. The bolt hold open may just be worn, they were never great to hold open the op handle. If the bolt doesn't stay back when last round is fired, you need the mag followers that are cut square for that. The 30s had those, not all the 15s did. Just a few I've seen...you can get or modify the followers to hold open though.

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Thanks BAR. I'll try giving the spring and plunger to see if they're gunked up. I've started looking for mags with squared off followers, and it looks like they're pretty rare. I've seen some postings here and there for South Korean manufactured 15 round mags with squared off followers.

'Preciate it!

Greg B

---------- Post added at 06:00 PM ---------- Previous post was at 05:58 PM ----------

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Originally Posted by JimF4M1s

The outside followers are angled, the inside two cut flat.

As BAR says check the spring and end plungers. They could just be gunked up with crud.

https://www.milsurps.com/images/impo..._zpsvnvu-1.jpg

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Thanks Jim. I'll start looking for the mags with the squared off follower. From what I've seen so far, it might take quite a bit of looking.

Cheers,
Greg B

The carbine does not have a bolt catch. The slide catch is kind of an afterthought and you shouldn't trust it by putting your hand in the action with it locked back. Lock back followers like the G.I. 30-rounder work, but the slide still slams shut when you pull the magazine out.
On the safety, most likely its as the others have said, its gunked up in the trigger housing. Put some solvent oil in the oil hole for the mag catch and safety springs and plungers and work those items to see if function improves.

If you look closely at the slide stop you will understand how it works. There is a hole with a sloped ramp toward the butt end of the weapon. When you pull the slide back and push the slide stop down it drops into the hole in the receiver. The stop pin is just held in place with a spring that side loads the pin around a barrel shaped center. When you pull back the slide the pin goes up the ramp which pushes it back into its unset position. It is actually a really slick piece of design. The two wear points are the hole and the pin. The hole can get buggered up and not hold the pin in place and the pin can be worn and have no sharp edge to hold the slide. You can simply turn the slide stop pin around 180 degrees to the fresh side and see if that works better. This can be done without taking it apart, Just a pair of needle nose pliers and turn the thing. The hole in the receiver can be dressed with a small jewelers file.

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Originally Posted by DaveHH

If you look closely at the slide stop you will understand how it works. There is a hole with a sloped ramp toward the butt end of the weapon. When you pull the slide back and push the slide stop down it drops into the hole in the receiver. The stop pin is just held in place with a spring that side loads the pin around a barrel shaped center. When you pull back the slide the pin goes up the ramp which pushes it back into its unset position. It is actually a really slick piece of design. The two wear points are the hole and the pin. The hole can get buggered up and not hold the pin in place and the pin can be worn and have no sharp edge to hold the slide. You can simply turn the slide stop pin around 180 degrees to the fresh side and see if that works better. This can be done without taking it apart, Just a pair of needle nose pliers and turn the thing. The hole in the receiver can be dressed with a small jewelers file.

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Thanks Dave. I used a bit of solvent and tried to clean it out as thoroughly as possible, and it did seem to work a bit better. I'll try your suggestion of turning the pin around and let you know how it works out.

And thanks to everyone for your suggestions and help. I know it was a noob question, but I'd quickly figured out how the side catch worked; it just didn't seem to work very well. Once the slide was all the way back, it would occasionally slam forward by simply picking up the carbine. Good info, and I'm an (already) older and wiser carbine owner.

---------- Post added at 08:44 AM ---------- Previous post was at 08:40 AM ----------

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Originally Posted by INLAND44

The carbine does not have a bolt catch. The slide catch is kind of an afterthought and you shouldn't trust it by putting your hand in the action with it locked back. Lock back followers like the G.I. 30-rounder work, but the slide still slams shut when you pull the magazine out.
On the safety, most likely its as the others have said, its gunked up in the trigger housing. Put some solvent oil in the oil hole for the mag catch and safety springs and plungers and work those items to see if function improves.

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Thanks Inland for the suggestion. I did apply some oil and it seemed to help. I'll find out for sure when I take it to the range. Thanks for offering to help with the Noob question. It could save me from replacing those parts.

Greg B

Thanks everyone for the help provided to a couple of Noob questions.

I've cleaned the slide lock and it's working much better. I've purchased a couple of new magazines of South Korean manufacture, which do have the straight cut mag followers. I hope to get to the range next week to see if they're functioning properly. Again, it's my first M1 carbine and I was making some (wrong) assumptions that it functioned similarly to my Garand.

I've also used some solved on the safety latch and it appears to be working much better than before. I'll find out for sure when I put some more rounds down range.

Finally, I love this latest addition to my WWII collection. When I was at the range last week, there were two young veterans (an Army reservist and a Marine) shooting in the bay next to me. They had all the latest toys (M4 carbine, a customized AK47, AR15, etc.) with high tech optics and add-ons. We started chatting, and they were really impressed by my little carbine. I let them each shoot a magazine through it, and they were grinning ear to ear afterwards. There's just something about handling and shooting a piece of history that makes a connection, especially for veterans. I know a 90-year-old gent who carried an M1 carbine across Europe in WWII, and he not only swears by its accuracy, he still shoots one at the range from time to time. He was an artilleryman, and said he wouldn't have carried anything else because of its 15-round magazine, light weight, accuracy, and that he could carry more "rounds per pound" than if he'd carried a Garand or Thompson.

Thanks again for your help!

Greg B

W&E:

Welcome to the Forum. If you have not already done so, you can very easily take the safety/magazine catch plunger assembly out and thoroughly clean the gunk out of the plunger assembly spring and the channel in the trigger housing. This is what should be done priodically and you don't even have to dissaemble the carbine to do it.

If you don't know how to remove the mag catch yet you just turn the carbine upside down and use a small steel drift or other pin type tool to retract the mag catch plunger by prying it back (toward the rear) through the small hole in the bottom of the trigger housing just behind the mag catch. When you get it back far enough the mag catch should release and pop out a little under pressure from the mag catch spring in the side of the trigger housing. Slide the mag catch the rest of the way out of the trigger housing and remove the mag catch spring/plunger from the right side of the trigger housing and the safety/mag catch plunger assembly from the front (in the mag well). You might have a hard time getting the safety/mag catch plunger assembly out due to the built-up gunk and/or rust but a pair of needle nose pliers and a shot of WD-40 or Liquid Wrench will get it done. When the safety/mag catch plunger assembly is removed the safety will just slide out of the trigger housing.

Then you can really clean the safety, magazine catch, safety/mag catch plunger assembly and the mag catch spring/plunger good with a brush and solvent. You can also really clean out the channels in the lower trigger housing using Q-tips and pipe cleaners to get all of the offending garbage out before you reassemble the parts in the reverse order of disassembly. Remember to oil the parts and trigger housing channels before reassembly.

FYI, the operating spring guide in your carbine was designed as a tool to be used in the field for prying back the safety/mag catch plunger assembly to remove the mag catch and safety as described above, as well as other maintenance disassembly tasks. Once you have taken the thing apart and put it back together it will seem very simple. You shouldn't have to remove and clean these safety/mag catch parts more than about once a year unless you really get down in the dirt with your carbine. HTH ChipS

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Originally Posted by ChipS

W&E:

Welcome to the Forum. If you have not already done so, you can very easily take the safety/magazine catch plunger assembly out and thoroughly clean the gunk out of the plunger assembly spring and the channel in the trigger housing. This is what should be done priodically and you don't even have to dissaemble the carbine to do it.

If you don't know how to remove the mag catch yet you just turn the carbine upside down and use a small steel drift or other pin type tool to retract the mag catch plunger by prying it back (toward the rear) through the small hole in the bottom of the trigger housing just behind the mag catch. When you get it back far enough the mag catch should release and pop out a little under pressure from the mag catch spring in the side of the trigger housing. Slide the mag catch the rest of the way out of the trigger housing and remove the mag catch spring/plunger from the right side of the trigger housing and the safety/mag catch plunger assembly from the front (in the mag well). You might have a hard time getting the safety/mag catch plunger assembly out due to the built-up gunk and/or rust but a pair of needle nose pliers and a shot of WD-40 or Liquid Wrench will get it done. When the safety/mag catch plunger assembly is removed the safety will just slide out of the trigger housing.

Then you can really clean the safety, magazine catch, safety/mag catch plunger assembly and the mag catch spring/plunger good with a brush and solvent. You can also really clean out the channels in the lower trigger housing using Q-tips and pipe cleaners to get all of the offending garbage out before you reassemble the parts in the reverse order of disassembly. Remember to oil the parts and trigger housing channels before reassembly.

FYI, the operating spring guide in your carbine was designed as a tool to be used in the field for prying back the safety/mag catch plunger assembly to remove the mag catch and safety as described above, as well as other maintenance disassembly tasks. Once you have taken the thing apart and put it back together it will seem very simple. You shouldn't have to remove and clean these safety/mag catch parts more than about once a year unless you really get down in the dirt with your carbine. HTH ChipS

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ChipS,

Thanks for the info and suggestion. I followed your suggestion and took down the mag catch and safety assemblies and gave them a thorough cleaning. There was quite a bit of gunk built up in the channel, but some solvent, Q-tips and pipe cleaners did the job. Everything is oiled and reassembled and working better.

Again, thanks for the help!

Greg B