Help on barrel ?

[jim70739]

Does anyone out there know where I can find a dimensioned drawing on the M1 Carbine 2-piece barrel? I want to replace the gas cylinder on one of my barrels. Thanks

[Tuna]

It would depend on the type of barrel you have. A type 1 is not replaceable as it's one solid piece with the barrel. While a type 2A may look like it can be replaced, it was not designed to be replaceable as the barrel is swaged onto the gas cylinder. If you have a bad gas cylinder then consider the barrel to be toast and replace the barrel.

[jim70739]

It would depend on the type of barrel you have. A type 1 is not replaceable as it's one solid piece with the barrel. While a type 2A may look like it can be replaced, it was not designed to be replaceable as the barrel is swaged onto the gas cylinder. If you have a bad gas cylinder then consider the barrel to be toast and replace the barrel.

If you look around, you will find that gas cylinder replacements were made for replacement on those that were swaged in. I have two "used" made by Inland that I plan to use as the replacement. I may end up building a "new" M1 Carbine barrel from the other. I have absolutely no intention to throw a barrel away that is a 2-piece barrel because of a simple gas cylinder. I just want to be sure what is underneath the cylinder when I machine the '03 down to carbine dimensions. I can measure all but what is underneath the cyl. Thus my asking about dimensioned drawings.

[JimF]

. . . . . I just want to be sure what is underneath the cylinder when I machine the '03 down to carbine dimensions. . . . .

If I’m understanding your above statement correctly, you have an ‘03 barrel (30-‘06 cal., 10” twist) that you want to machine down into carbine configuration.
Accuracy may suffer because the carbine barrel . . . using the GI bullet of 110/111 grains . . . used a 20” twist.

[Allen]

If I’m understanding your above statement correctly, you have an ‘03 barrel (30-‘06 cal., 10” twist) that you want to machine down into carbine configuration.
Accuracy may suffer because the carbine barrel . . . using the GI bullet of 110/111 grains . . . used a 20” twist.

There were plenty made like this. Some ended up being 4 groove, some 2 groove. They were used on commercial carbines made in the 60's like Federal Ordnance. I have a few of them. The cylinder was shaped like a tiny barrel and welded to the bottom. The barrels had no skirt (bullet guide). Kinda goofy looking but they worked.

Yeah, accuracy probably suffered but the object of the game was to use up surplus barrels and make commercial carbine copies as cheap as possible.

File picture from the internet.

[Tuna]

If you look around, you will find that gas cylinder replacements were made for replacement on those that were swaged in. I have two "used" made by Inland that I plan to use as the replacement. I may end up building a "new" M1 Carbine barrel from the other. I have absolutely no intention to throw a barrel away that is a 2-piece barrel because of a simple gas cylinder. I just want to be sure what is underneath the cylinder when I machine the '03 down to carbine dimensions. I can measure all but what is underneath the cyl. Thus my asking about dimensioned drawings.

I do not think they were made as replacements. I would say they were left overs from normal production and just appeared on the surplus market. As I said there was no listing for them in the TM's and the only replacement was the whole barrel. The problems never were with the 03 barrels. It was with the receivers. Many of them were cast and not well done heat treatment wise. Quite a few were made overseas reportedly in Spain and were sub-standard. You should be OK with an 03 barrel.

[lyman]

quick googley search netted nothing,

never seen a blueprint or dimension drawing for a Carbine (have seen them for 1903's etc) which means nothing,

I can wrap my head around replacing a barrel by drilling out the original and putting the original gas cyl on the new barrel, but not sure how to go about putting a new gas sys on an original barrel, other than turning the original down and sleeving another to it,

any machinist should be able to do that for you without much effort

[jim70739]

quick googley search netted nothing,

never seen a blueprint or dimension drawing for a Carbine (have seen them for 1903's etc) which means nothing,

I can wrap my head around replacing a barrel by drilling out the original and putting the original gas cyl on the new barrel, but not sure how to go about putting a new gas sys on an original barrel, other than turning the original down and sleeving another to it,

any machinist should be able to do that for you without much effort


I have started machining the 03A3 to a Carbine configuration and it looks like there is barely enough meat to machine the Carbine shape just barely. Working on the chamber end right now. The cutoff drill rifle is plenty long enough just almost laking meat on the chamber end to get the shape down to the gas cylinder fit. Not bad for a mini lathe and mine mill.

[jim70739]

The old gas cylinder is easy enough to get off even trying to salvage the barrel. I picked up a demilled barrel from Sarco and was able to remove and find out what is underneath a gas cylinder. It is basically like what was said here.
Thanks all...

[jim70739]

There are two different type barrels, one piece and two piece. I am re -doing the two piece only. The gas cyl. will push off and on easily enough. Would not attempt it on the one piece and take a chance of messing up a good barrel unless it was the only option I had.