Look out! It's a newbie with carbine problems!

[Bubba-7]

Nothing, I would expect.
0.070" should be the size of the hole.
The piston does not have to fall with a tilt. But should(most of the time) with a tilt and tap on the side of the housing.

[Rustship]

The hot rod is powered by an Edelbrock headed 440 wedge. It's got a custom port injection intake of my own design, 1700 cfm throttle body, and 120 lb injectors. The ignition is distributorless and controlled by the EFI system.
It's street manners are so nice that I drove it from DFW to Green Bay, WI on the Hot Rod Power Tour.

Damn Feets, I guess I read it wrong, I was under the impression you had stuck a Big Block CHEVY in that Mopar. I gave you credit for having some sense...HHHMMMMM...LOL. My Chevy's have no manners at all, they only like to go 1320 ft. And they like to get there First.

[feets]

Nothing, I would expect.
0.070" should be the size of the hole.
The piston does not have to fall with a tilt. But should(most of the time) with a tilt and tap on the side of the housing.

When I got home from work today I was happier than a puppy with two peters. My new/old M2 stock was sitting on the porch and right next to it was my Criterion barrel.
That barrel sure is purty!

The stock looks good too. I've already dropped the carbine in it's new wood. The tension seems pretty good as-is. It's kinda funny not seeing the almost-tacticool stock on the gun. The GI stock lends a little more credibility to the package.

Anyway, back to my issue.

I did some digging into the problem and I believe there should be no adverse effects to my butchery. Since the orifice is still the stock size it doesn't matter that there are two holes feeding it. Considering that one of them is half plugged it should help.
I got all worried about it without thinking it through.

Just to hedge our bets, I'll build some lightweight Trail Boss loads and see how the response of the action compares to the unmolested carbine. I'm fairly certain what will happen but I want to start off with low pressure and a control. I'll walk the pressure up to normal levels in a couple steps to see how it goes. If the two carbines start to feel different under recoil (op rod and bolt battering) then I'll shut it down and make immediate plans to rebarrel. If not, we'll have a little fun with it.
It will be interesting to see if this fixes the feeding issues. If the FTE problem is gone but it still fails to feed I'll have to find a cheap GI action to put my purty new barrel on.

Off to the loading bench I go...

[Harlan (Deceased)]

New receiver? After the parts already, then the barrel, and also a stock wouldn't you just have a pile of leftover IJ parts?

Seriously, there's no such thing as a cheap USGI reciever especially when none of the IJ parts will work on it. Wouldn't you be better of returning the stock and barrel and save a little more to buy a complete original carbine that'll have history and also hold it's value and probably appreciate? You could probably sell the IJ and just put the money you're spending for parts already and buy a GREAT import original M1 carbine.



JMHO
~ Harlan

[JimF4M1s (Deceased)]

I agree, spend your money wisely.

[jackthesmib]

Phew - those commercial carbines sure are a pain.

[feets]

This commercial carbine has been hacked. GI carbines get hacked too. I'm getting my jollies fiddling with it and trying to make it run.

I really don't care about resale value. I've only rid myself of one pistol and one revolver in my life. Both of those were replaced as time passed. I don't buy a gun unless I enjoy using them. The carbine is one of those things that make me happy. Tinkering with things makes me happy. Even this early in the project, I've gained more practical knowledge about the function of this platform than many owners ever will. I have a bad habit of getting a new mechanical device and taking it apart as soon as I get home. This thing is a toy and part of playing with it is figuring out how to make it run.
It's true that I could spend a wee bit more money and get a Blue Sky gun but it would come with a barrel that is nearly 70 years old with an unknown round count. Muzzle and throat erosion are a total crap shoot.
Doing things this way guarantees that I'll have a new barrel. I like bolt gun accuracy. I like carbines. Those two things don't go well together. Hopefully, this one will get about as tight as can be expected out of a carbine.

We went to the range again last night. The first thing we learned is that 4.2 grains of Trail Boss under a 110 gr bullet sounds slightly louder than a 10/22 and only jiggles the action. The carbine was a single shot but it held a 2" group at 50 yards. I expected the bullets to keyhole at that soft of a load but it didn't happen. I then stepped up to entry level loads for the carbine. 12 gr of H110 gave me mild recoil and the action worked through 10 rounds before giving me a failure to feed. Moving to Aguila factory loads repeated the performance. When we ran heavier loads with 14 gr of H110 the gun started failing to eject as well as failing to feed.
What I draw from that is the new and improved port is allowing more gas to get into the block. That probably has something to do with the original being clogged as evidenced by the aerosol test. The high pressure loads seem to be working the bolt a little too fast. I think the extractor was jumping off the rim of the case. There were no signs of the bolt or op rod being battered.

The failures to feed are all identical. The round hits the end of the barrel and the bolt runs over the base. I really think it's the breech face. The barrel has a shadow that looks like a radius or ramp but the real bevel is only a couple hundredths of an inch wide. All they did was break the sharp edge on the chamber.



The Inland has a nice radius to the breech.



Same goes with the Criterion.



After returning from the range, I pulled the barrel on the IJ to cut a similar bevel on the breech. When I chucked it in the lathe the run out was horrible. No matter how I positioned it or what adjustments I made it would not straighten out. The barrel is a bananna. When laid side by side or even rolled against one another you can't see an appreciable difference in the original and Criterion barrels. Chuck them in the lathe and it's like a shovel to the forehead. The Criterion has less than .002" runout while the IJ barrel visibly flops around.
When compared closely you can see that the gas block on the IJ points upwards while the Criterion's block is parallel with the bore.

Tomato stake!

I trimmed the skirt off the Criterion barrel and began fitting it to the action. It's currently fitting tightly with less than 10 degrees to go to be aligned. I'll pull the barrel again to clean the threads and make sure there's no debris getting in the way before I make any changes to the receiver or barrel.
I'll rent a reamer and gauges and finish the barrel next week. I've got too much going on this weekend to mess with it.

[phil441]

Still too short for a respectable Tomato Stake!

[Harlan (Deceased)]

Even this early in the project, I've gained more practical knowledge about the function of this platform than many owners ever will.

We are all here to learn. Please continue.

[feets]

We are all here to learn. Please continue.

Step 1: If you don't want to spend lots of quality time with a carbine OFF the range, be very VERY careful what you pick up from an individual at a gun show.


I really don't have any regrets about buying this carbine. It will cost more than a common commercial gun and I'll have lots of time in it. However, the new barrel should make up the difference.

Now, what publications should I peruse to find tips on making this thing perform at it's best?

I'm thinking about changing the barrel clamp while I've got it torn down. Is there one style that is more desirable for consistency and accuracy? The unit I have requires plenty of effort to get it over the nose of the M2 stock.