aftermarket 30 m1 carbine question

[mountainman]

Hey there I have a national ordinance 30 m1 carbine and I am having functioning problems with it. I was going to pull the gas assembly apart but the piston nut does not match up with the nut wrench. (only has 2 lugs not 3) Can anyone tell me if I can use a usgi nut and piston on this rifle or am I doomed to spend eternity with this system. Also I was looking at the carbines inc sight and noticed that my gas system is welded on as apposed to the 2 examples that they showed. Does anyone have any ideas about this.
Thanks

[HangFireW8]

Hey there I have a national ordinance 30 m1 carbine and I am having functioning problems with it. I was going to pull the gas assembly apart but the piston nut does not match up with the nut wrench. (only has 2 lugs not 3) Can anyone tell me if I can use a usgi nut and piston on this rifle or am I doomed to spend eternity with this system. Also I was looking at the carbines inc sight and noticed that my gas system is welded on as apposed to the 2 examples that they showed. Does anyone have any ideas about this.
Thanks

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[curator]

I got one of those myself. Most functioning problems are due to magazines. Some work, others do not. Here's a link to a site that will give information about your M1 carbine and US-GI compatibility:
http://www.m1carbinesinc.com/parts.html

[mountainman]

Thank you curator I ordered the new gas parts after I read this. The main problem is that different ammo gives different results. I had factory winchester ammo that worked flawlessly in all of my magazines. I had wolf ammo that would not produce enough power to fully extrack the spent cartridge or when it did I got a stove pipe malfunction. I also tried reloads with a semi j word bullet and the lead nose would catch on the feed ramp an gouge the nose. My next attempt is a cast boolit from a lyman 311359 mould and imr 4227 powder. I used h110 with the other reloads and performance was sketchy at best. Thank you for the info.
Craig

[Larry Gibson]

I used h110 with the other reloads and performance was sketchy at best.

What specific bullet and what load of H110?

As mentioned magazines can give a lot of feed problems and if your M1 Carbine is just a "shooter" is suggest you polish the feed ramp.

Larry Gibson

[leadman]

The Wolf 30 carbine ammo got a bad rep on the CMP boards so the CMP no longer sells it. I did shoot next to a young guy at the range that used it with no problems.
The OAL of the cartridge needs to be close to factory ammo to work good in my guns so you may check that. I use 14.5grs of H110/W296 with a 110grs jacketed bullet in mine. With cast I can go down to about 12.5grs with great accuracy and functioning. Case trim length is also critical.

[mountainman]

I used h110 with the other reloads and performance was sketchy at best.

What specific bullet and what load of H110?

As mentioned magazines can give a lot of feed problems and if your M1 Carbine is just a "shooter" is suggest you polish the feed ramp.

Larry Gibson

I was useing a 100 grain bullet I don't know the brand because I got them in a trade and they came in a jar with no nomenclature. I weighed them and they came to between 97 grains and 101 grains. The load was h110 and I started low at about 12.5 grains. The results were that some cases would extract and some wouldn't even move the bolt back enough to cock the hammer. It was wierd I have never had a rifle behave this way. I weighed every charge bu some seemed to have a greater amount of power. I am wondering now if I don't have other issues aside from the ammo. Oh the bullet kind of resembles the speer 100 grain plinker listed in their reloading book.

[mountainman]

thank you leadman I will check the length of case and over all length. I just set the bullet to what the guide said was the c.o.l. but there are different lengths for different bullet designs.

[Larry Gibson]

That 12.5 gr H110 is a bit light for that weight bullet. I use 15.5 gr H110 with the Hornady 100 gr HJ or the Speer 100 gr Plinker for 1950 fps out of several M1 Carbines. Suggest you work up to 15 gr at least. You also might want to mic the bullet diameter as that is a large weight spread for Hornady or Speer HJs. Might be some home swaged bullets? if under size and loaded low the results could be what you describe.

Larry Gibson

[mountainman]

thank you Larry I'll give that a try this weekend and see.

[Job]

I have one too, a Natnl ordnance (from the early 60's as far as I can tell) with some GI parts and a barrel with the welded-on gas system. I am having the same ejection problems as mountainman. After replacing the springs and the piston/nut things improved, but still a failure or two every 15 rounds.

I just discovered small gaps in the front and rear of the gas block between the block and the barrel that allow gas to escape that is undoubtedly causing the problem. There are no cracks in the gas block or barrel itself and no cracks in the welds (on the sides). There is simply no weld on the rear of the block where it meets the barrel.

Does anyone know if having that welded is possible or a reasonable idea?
Thanks.

[Larry Gibson]

Does anyone know if having that welded is possible or a reasonable idea?

I have seen 2 such barrels "cured" by a good tig welder........remove the gas nut and piston before welding.

Larry Gibson

[Job]

Great. Appreciate the info, Larry.

[Job]

Does anyone know if having that (gas block) welded is possible or a reasonable idea?

I have seen 2 such barrels "cured" by a good tig welder........remove the gas nut and piston before welding.

Larry Gibson

Update for anyone with the same gas system issue: I had the gas block TIG welded in two small spots. $45. Good as new; I shot approx 100 rounds last weekend with zero failures. Thanks again, Larry.

[n.h.schmidt]

I have seen the piston housing welded on,swaged on,braised on and forged as part of the barrel. I used to buy 30 carbine barrels at gun show when they were cheaper. My prize strange barrel for 30 carbine has a two groove bore. With a one in 10" twist. This had to have been made from a two groove springfield barrel. It does look nicely made and not some basement made conversion.
n.h.schmidt