M1 carbine gas piston nut types

[Froglegg]

I'm working on an m1 carbine for a friend. It's a universal firearms commercially produced m1 with a stuck gas piston. I was expecting a simple removal and cleaning, and installing a new nut. As I went shopping for a wrench and a new nut, I discovered that the nut installed in the gun is different. It has 4 slots instead of three. Every wrench and nut I've found on the internet has three slots.


Removing the old 4slot nut isn't a big deal. I have a little hobby lathe, files and a cheap tig set up. I can make a 4 slot wrench easily. My question is, Can I go back with a three slot gi nut? Does anyone know enough about these universal firearms M1s to have some advice? Im reluctant to just RIP it out and buy a new one only to have the replacement not fit and the old one not supposed to be reused.

 

[Carl N. Brown]

A removed M1 carbine piston nut is usually staked in place with a punch.
Removal with a wrench usually just undoes the staking leaving a burr on the housing and leaving piston nut in reusable condition.

I am going by my experience with my IBM made WWII M1 Carbine and the combined US Army Field Manual/Air Force Tech Order I have used to keep mine running in twenty plus years of matches and general plinking.

The M1 has not been made with corrosive primed ammo in US military or US commercial manufacture. The FM/TO recommends running the gas system dry and cleaning the gun "upside down" so cleaning fluid or oil does not enter the gas system. It is supposed to be self cleaning from hot noncorrosive gases in normal service. M1 Carbine gas nut and pistol would get removed and cleaned once in a blue moon by the unit armorer, usually when taken out of issue and thoroughly cleaned before going into reserve.

Universal started using surplus GI parts and as the surplus dried up they did redesign their carbines. That should not change the basic operation of the design.

The gas nut should be properly hardened steel and reusable after removal.

 

[CapnMac]

It's a universal firearms

So, atypical fixtures will be common.
GI wrenches will likely not suit at all.

You may want to include "Universal" or "Universal Carbine" in any tools searches.

The Universals are not faithful reproductions of the M-1 Carbines, but just copies that shared some parts to start, but had an increasing number of non-GI parts over their years of production.

 

[Froglegg]

The gas nut should be properly hardened steel and reusable after removal.

I kind of figured it would depend on how badly the stake marred the nut on removal. I can get a small needle file into the staked area to remove a little of the upset metal and maybe give the nut an easier time out. I have lots of taps, and can clean up the threads in the gas block if needed. I guess I will try to remove the nut without damaging it to much, and try to reuse it. I work in the inspection industry and have plenty of dye penetrant and mag particle resources available. The nut and gas block will get a thorough inspection for cracking before anything goes back together.