3006 M2 Ball Cartridge as a Gage for Carbine

Emmett Dunham

The post that just went locked the poster asked for a way to check a M1 carbine barrel with out a gage. I have read and seen a complete work up of the M2 Ball round and a ME gage so someone with out a gage could check their carbine. He Took the M2 bullet-cartridge all the way down to the lowest numbers of the ME gage. It does not make any difference what the diameter of the 3006 is compaired to the .30 carbine, it is getting a rough tool for someone who has no gage. If you slide the 3006 bullet, cartridge in the carbine barrel and there is a quarter inch between the case mouth and the muzzle you have a good barrel, if you put the cartridge in and it goes all the way to the case mouth the barrel is shot out.


Emmett

v35

Emmett
Before using those barrels as tomato stakes, try a slight bend to correct POI.
If you have a Mk-1 eyeball, maybe you can see they weren't straight in the first place.

Emmett Dunham

I read about the process of professional straightening the barrel the cost is to high. One gentleman said he could look down the barrel and see the shadow and determine the direction of bend. There was the string method. On guy said he had a tree in the back yard he used to bend barrels. I would love to make two good barrels out of these I just don't want to spend the money to correct them and am always looking for a repair for them. They are both setting in a box in good condition hoping that I may run into a solution. Question is how do you make a slight bend?

I will get them out and play with them when I get some time!


Emmett

v35

As you said, there's a huge windage issue so you don't have to determine straightness. You already know the direction to bend and don't need the MK-1 eyeball.
Manually eyeballing barrels has been done in factories forever though there may be newer techniques.
I've seen pretty primitive setups comprising an arbor press and two blocks used in a factory. A large C clamp might even work.
If you had a dial indicator and a flat surface you could measure the amount of bend and return to a known dimension if you overshoot.
In trial and error bending, place supports and bending device in same places each time.
I'd install barrel in the receiver and by trial and error make very minute bends and shoot.

wpage

Good information. Why not get a quote from the pros to see first...
http://www.thecmp.org/m1garand.htm

nmyers

I don't know. I've seen shotgun barrels straightened by experts, but rifle barrels are not so easy to do.

There was one large batch of carbine barrels that were bent in half by the manufacturer & sold as scrap. Some enterprising person "straightened" & sold them, & it wouldn't surprise me if Emmett's barrels are these turkeys.

You will see Herlo "milsurp" carbine barrels offered, but these were rejected by the US Military because they failed to meet specs. These are also problematic.

There is a seller on GB who offers "NOS" carbine barrels that actually demilled barrels with a new flash hider welded on the front. I have never examined one of these, so I can't comment.

CMP has never offered commercial carbine barrels. However, Fulton Armory sells them.

Good USGI barrels are difficult to find, & you will pay $300-400 if you are lucky. Plus gunsmith charges to R&R the barrel.

Neal