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

Yeah, I'm another newbie with issues. I've come here in hopes that you folks will know more about these things than anybody else on the planet.
While I'm not new to the Garand action and it's derivatives, I am a little new to the carbine. Like many of you, I'm kicking myself HARD for not picking up one or two (dozen) carbines when they sold for less than $200.

I've been wanting to quench my thirst for a pistol caliber carbine for plinking and a Mini 14 because I really enjoy them. The often overlooked M1 carbine was a viable option. I'd seen them around but never tried one on and certainly didn't take them seriously. When a friend picked up an Inland, I talked him into letting me take it out for a walk. I dumped 16 rounds into less than 3" at 50 yards my first time out and I was hooked. These things are like 10/22s for big boys! That clenched it for me. The cutesy little M1 Carbine would satisfy my "needs" for both types of guns. I had to have one.
My plans for the carbine involve tin cans, bowling pins, various other things that need shooting, and no doubt many things that really shouldn't be shot. Stepping up to a progressive reloading press will be beneficial.

After doing a little research and getting hurt by tons of sticker shock, I settled on (gasp!) a commercial variant. While I don't abuse my firearms, I certainly put them to use. The carbine will end up as a truck gun so to speak and I really don't want to beat up a collectible piece.

I brought home an Iver Johnson dirt cheap. The wee beastie seems to have full interchange with the GI versions. We tore it down and played mix-n-match with that Inland. Believe it or not, the Inland's bolt even drops in with good head space.
The disturbing part is that it was seriously Bubba'd. You see, Bubba had some sort of problem and tried fixing it with a welder, grinder, and felonious use of a hacksaw.
I think the gas cylinder split at some point in time. Bubba, being the fix-it sort that he is, tried to put the gas cylinder back together. Apparently, he was unable to remove the piston nut and took out his frustrations on it using a hacksaw. Think of it as Leatherface defending his family's honor with a chainsaw.

https://www.milsurps.com/images/impo...212256_9-1.jpg

Careful inspection of the weld shows that it's far from pretty but it should not fail. However, the gun doesn't run properly. It has a random failure to feed at least once per magazine. We used three mags including those that run in the Inland. It's a bolt over base failure like this:

https://www.milsurps.com/images/impo...212256_9-1.jpg

I'm assuming that much of the problem comes from the gas port and piston. I wasn't smart enough to bring along more than one type of ammo so I can't rule that out.

I'd like to pull the nut off the barrel but I simply can't get it to turn. A sharp punch and mallet won't do the trick. I can easily clean up the welds and repair the damage assuming he didn't cut too far back into the gas block. The problem is the piston is in the way and I can't take my usual approach to removing damaged fasteners. I'm a hot rod guy with a machine shop at home so labor cost isn't an issue.

There's a good chance I'll have to rebarrel the receiver. If that's the case, would it be a better idea to use an in-spec GI barrel or one of the aftermarket barrels? Who makes those barrels? Is there any accuracy advantage to be gained with new vs in-spec GI?

No doubt this post looks like a train wreck but I'd appreciate any input you folks could offer. Think of it as me abusing this old turd instead of bashing around with that Rockola I really want. :thup:

Best deal on barrels now..
M1 M2 M1A1 Carbine BARREL Back In Stock! : Barrels at GunBroker.com

Ditto what FTD is saying. Dump the barrel and have a new one installed. Don't risk a catastrophic failure with that hunk of junk barrel that's on it.

I've seen the new barrels for sale. They look tempting but I don't know how difficult it would be to ream the chamber and get it right. I did read up on the new barrels thread.

Yea, my Pa-in-Law did that one. I remember he called me first. I was glad to help him out. I would not spend a penny on it. Keep it as a fun/teenager gun. You usually don't have to worry about coke can shooting back and will wait for you to clear a problem. To rebarrel, you will put $300.00 in to a commerical carbine. Save that for a future GI carbine purchase.
And PaPa did good work, didn't he? You should have seen it before.

Oops! Wrong Bubba! :lol:

I want a shooter that I can take anywhere. If I rebarrel this little guy I will have less money in it than what a GI unit would cost but it would have a brand new barrel.
I sold off some gun stuff I haven't used in nearly 15 years and will use that "gun money" to handle the work.
I'll probably toss the carbine's pre-tacticool stock on arfcom and see if it can find a new home. That will help a wee bit too.

Again, since I'm going to mix-n-match pieces parts I think it'd be best to do it to a commercial receiver and leave the numbered stuff to the collectors.

There is Big Bubba, aka Pa-in Law, and seven of us little Bubbas. I have another brother-in-law we call "Shade Tree". You may have ran across some of his work before. I was just trying to give you a different take from the others above. I would not put a penny into a commerical carbine. Oh, I have said that before. There are other problems many commerical carbines have. You can put $300 into this one now and week or next year there is something else.
They are not made the same.
They are not made as well.
They will not hold up as well.
I just want you to hear the rest of the story.

I tend to agree with Bubba about throwing good money into a commercial carbine repair project. Guess it kinda like owning a boat (A boat is a hole in the water you throw your money into.). First you have to buy a barrel (those that FTD pointed out run $129 plus shipping). Then you have to either buy the wrenches and block or pay a smith to dismount/mount the barrels. After that you have other parts, like piston, nut and front sight key (assuming the front sight and barrel band are re-usable). With the replacement barrel in the white, you will have to repark at least the barrel if not the entire receiver. Next step will be to have the smith finish cutting the chamber to proper headspace. Each of those steps cost smoe cash for either the tools (for DIY) or services of a smith. Once you are finished, you will have an Ivers Johnson carbine which will not wear well and may have other inherent safety or mechanical issues. They were not the best commercial carbines by a long shot.

If you are looking to get a good truck carbine, you may be financially better off buying a "less than desirable" import marked mixmaster from some of the available sources (Big 5, Dupage, etc). it will give you a better quality gun (even in bad condition) and a safer to operate gun. You will even have your IJ as a source for spare parts (slide, bolt, etc).

I can not help but think of the 40,000 psi about 6 inches from my face when I shoot a carbine - that is why the ONLY Universal I own stays tucked away in the back of the safe never to be fired by me again.

Just my own two cents worth....

I'll pick that gravel off your back.

I think sell the GI parts off, and that should get you most of a shooter USGI off GB ($550-600)

There are no GI parts on this one. I played mix-n-match with parts from a friend's Inland and everything seemed to fit. naturally, I gave him back all of his GI parts.

I polished the ramp last night. I also removed some of the welding and exposed the parting line between the piston nut and gas cylinder. Then, the little guy got a detailed cleaning and reassembly with proper lube. The Inland is going to come visit this afternoon and we'll make a run to the range for further evaluation.

I went to Fulton Armory's site and ordered a new piston, nut, wrench, op rod spring, spring guide, and a sling for the stock I have coming in.
When the parts arrive, I'll get the old piston out, dress the butchery on my mill, and install the new parts. I have the feeling it will straighten out. If not, I'll weigh my options. The above parts represent a small investment that can be applied to any GI spec carbine.

And you will learn alot about carbines in the process. Good choice sir.

I enjoy tinkering with mechanical things. That's why I've got a machine shop at home despite not being a mechinist for a living.

We took the carbines to an indoor range last night. It showed a couple failures to eject and failures to feed on each magazine fired. We swapped parts one at a time to see if it would help. We tried his bolt, recoil spring, guide rod, and magazines. It still exhibited the same issues.
When we got home I noticed that the gas cylinder was cracked on the bottom. It gave itself away by the gas residue on the gas cylinder. I notched the crack and welded it up with just enough heat for a good weld but without heating up the barrel. The welds were ground and polished without heating things up. After a thorough cleaning to get the metal, grinding, and polishing residue out of the carbine it was reassembled and put away for the night.

My shooting group had a range day this morning. I stopped in before work and ran a magazine full of Remington FMJ through the carbine. It had one bolt over base failure to feed on round 8 of 15.

When welding the gas cylinder I closed up about half of the vent. The piston is so chewed up that there is lots of extra gas getting around it. I hoped reducing the port would help put more gas on the piston and increase function. I can easily open it back up when the new piston and nut arrive.
Another thing that is rather annoying is the front sight is canted to the right. I can see that it's tight but not centered on the key. I'll knock the pin out and try lining it up better.

Again, I can futz around with this barrel's gas cylinder and not be too worried. I'm not weakening it structurally and if I can't get it to run I'll change the barrel. Unlike many butchers out there I have a clue what I'm messing with. My purpose in coming here was to find people that know more about carbines than I do. I don't have an ego and am not afraid to learn from others.

As it is, I'm having fun tinkering with the carbine. When I get it running I'll probably have to go back to wrenching on the hot rod to get my fix-it fix.

The part of the gas piston that works is inside so it is not buggerd up at all. The part you see is used to drive the slide back. It has no effect on the gas system.

If the sight is cocked to the right the barrel has been under tightened. Taking the front sight key or pin will not allow you to fix the problem.
Dave

Quote:

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Originally Posted by feets

I hoped reducing the port would help put more gas on the piston and increase function. I can easily open it back up when the new piston and nut arrive.

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I don't follow your reasoning. Why would closing down the port put more gas behind the piston? Seems like such throttling would actually allow less gas into the chamber and so reduce the pison's "push".

I understand that the head of the piston lies behind the nut. It creates the seal. The portion passing through the nut is essentially a pushrod. It's been mutilated. I can't help but think it could be allowing the piston to tilt slightly, especially if the head is a loose fit in the non-GI barrel.
There's the whole thing about the missing mass too. That would cause the piston to react quicker but I'm not sure if it would have an appreciable impact of the force applied. Lighter bullets moving fast are easier to stop than heavy bullets moving slow. This whole train of thought may be getting too deep and may not make any difference in the operation of the rifle. Theories are wonderful but facts make the world go 'round. The new parts will be in next week so I was just playing with what I had to work with.

I keep reading the signs as too little movement on the op rod. There doesn't seem to be proper force pushing the slide rearward.
Closing the vent would put a little more push behind the piston. Considering the angle of the vent it looks like it would be exposed when the back of the piston passes it. This is pure speculation since I can only see threads on the nut behind it.
I did not weld it closed. That would mean being dangerously close to welding the threads of the nut to the cylinder. I closed most of the exit without filling the void underneath. That will not increase pressures dramatically. At most, it will increase the velocity of the gas exiting the port. Pressure behind it will increase slightly but is shouldn't be an appreciable amount. It's more of a split second timing kind of thing.

Cannons, I didn't close the hole in the barrel. I closed the vent that allows the gas to escape the cylinder after pushing on the piston. It vents from the gas block into the stock.

Collector, the sight is not in perfect alignment with the key. I imagine the barrel might be a degree or two off but I can see where the sight seemed to be a loose fit on the key until the pin was pressed in. Whipping up a little fixture to hold it in place while I reinstall the pin should be easy.

There is no hole that allows gas to escape. There is a drill hole used to drill through into the barrel. After that the nut's threads covers the hole. You can have a point about missing mass and if the end of the piston no longer square. I can not state how either would effect function. Might some or might not. Thoughts to ponder. If the piston was shortened it could affect slide speed the same as a gas port partally closed. I have seen gas ports not cleaned out with drill cuttings partly in them. Not lead but steel.

I guess I missed the point on the drill port. I was thinking it was an exhaust like I'd seen on some other actions.
Not a problem. It'll open up in a couple minutes of work.
Checking the gas port in the barrel would be a grand idea, don't you think? I kinda blew right past that one since I can't get the stinkin nut out.

I've tried all kinds of things to clean out the gas cylinder. Not being able to get the nut off puts a damper on the fun. I've sprayed my heavy duty action cleaner all around it multiple times as well as dumping Hoppes in there. I make sure the piston is all the way forward and hold the action muzzle down for that. After a good soak, I turn it muzzle up and fiddle with the piston. Whenever it pokes down the sides are covered is black nasties. Last night was the first time I was able to get it to move by tilting the action. Disturbing, eh? Most of the time I have to use a pair of pliers to rotate the piston and pull it rearward. There are some clockings of the piston that won't let it move rearward without a fight. No doubt that's killing the function. Granted, 40,000 psi in the chamber pushes harder than I can pull with pliers but if it's slowing down the works that can lead to FTEs and FTFs.
I just brought home $175 worth of dies, bullets, primers, and assorted items for the 30 carbine. I guess I'm in it for the long haul now. :super:

I'm going to the range tomorrow with my former armorer friend. If this was a 25mm Bushmaster cannon he could fix it right up but the little carbine pre-dates his service. Still, a day on the range is better than a day at the office. :D

I really can't understand why you're still fiddling around with that fubar'd barrel. The only way it could possibly be fixed so it would function properly is to replace the gas cylinder......providing the bore/barrel has'nt been ruined by being welded on multiple times. Welding on something that has to stay perfectly straight is no easy task, and it distorts the metal, causes warpage and changes it's structural integrity, not to mention putting it under loads of stress. Likely, the bore has a tight spot directly under the welded area or will be warped or both. Go with the original idea and rebarrel it or take everyone else's and scrap it and get one you don't have to worry about a barrel rupture on every time you pull the trigger. Theres a reason the originals have the gas cylinder swaged in place, IIRC Iver Jonnson and others silver soldered theirs on and thats the reason the weld cracked, impossible to weld over that stuff and get it to hold up. JMHO

Question; If it is soldered on , can it be warmed up and remove? Then replaced?

No, not warmed up, heated up and yes they could be but you really don't want to do that. They were silver soldered on, different process to lead based soldering, this would require heating the barrel/cylinder cherry red to attach or remove it. Not something you'd want to do under normal circumstances as it would likely require the whole barrel to be heat treated to remove stress. I've seen some replacement gas cylinders that were said to have made by Iver Johnson and were leftover when they ceased producing the .30 carbines. They were'nt the band type like seen on USGI barrels and on the IJ carbine I had they were silver soldered in place.

Vintage is right. There is no removing the gas block and saving the barrel. It would have to be cut off using a very slow and tedious process. I enjoy fiddling with metal but there's no way I'd go put that kind of effort into saving a barrel that is likely beyond saving as it is. Slamming through it with a cutoff wheel on a die grinder would cook the steel and leave you with a potentially explosive barrel. The uneven heating caused by that is worse than welding because of the duration of the heat generated.
If the gas block has to come off, the barrel is going in the scrap pile.

I'm just fiddling with it now. Think of it as goofing off in a mechanical way.
The welding I did was on the bottom of the gas tube. I did not weld on the barrel itself. The previous owner did some nasty welding and no doubt did nothing for the barrels precision (or lack thereof). I am very aware of what welding does to metal. I weld and machine all kinds of stuff. Sheet metal, steel structures, automotive stuff, tools for my guys at work, etc. I have a good understanding of physics and what temperature does to metals. I bet my life on my welding and machine skills, as evidenced by this photo:

https://www.milsurps.com/images/impo...15275_46-1.jpg

How many 1965 Plymouth Belvederes do you see running around with twin turbocharged fuel injected big blocks and 14" AMG disc brakes from a 2005 Mercedes S55?

Back to the topic at hand...

The interesting part is that the little carbine punches relatively tight groups. This barrel has had a bad day but shows no signs of fatigue, inside or out. A bore scope shows the inside to be free of hot spots, visible cracks (no witnessing from gas residue), or other bad signs. There appear to be no tight spots.
The piston and nut in this thing are trashed. I can hack away at it and do whatever I like. Replacement parts are on the way to me as we speak. When they arrive, I will weld a stick to the piston to help me hold it rearward. Then, I'll cut it off as close as I can to the nut. Once that's out of the way, I'll try a broken bolt extractor on the nut. Should that fail to remove it, I'll tack weld a piece of bar stock to the remains of the piston nut and use it to twist the nut. Once it moves it'll be easy to remove from the barrel. I'll stuff the new parts in there and see what happens. If the carbine still won't run properly, I'll rebarrel it using one of the Criterion pieces. The new barrels don't have any hardware so I need that new nut and piston anyway.

Welding and machining don't cost me anything. All I do is step from my living room into the garage and turn on the lights. I might even turn on the radio and fan if I'm going to be out there for a while. You see, I enjoy doing stuff like this. While I don't normally machine gun stuff I have made a few parts in the past. As a matter of fact, I got rid of the scary piece of brass that someone stuffed in the carbine as a trigger group pin and turned my own pin out of 306 stainless steel rod I had in the garage. I did not have a GI pin to measure at the time so I made it .005" undersize for a slip fit.

In short, I'm playing with the barrel to see if it will run well and group tight. If it doesn't straighten out, I'm really not out anything. I have learned quite a bit about the carbines and will learn more as I go.
If I simply threw this thing in the trash and bought something else I'd be out more money and would have learned very little.

Some people take their car to the mechanic when they have a problem. I'm the guy that studies the problem, does a little research on the subject, and gets my hands dirty fixing it. Guns are very simple mechanical devices. There's no voodoo or black magic going on. If you have an eye for detail and can comprehend what other things can happen throughout the system when one little change is made these things are easy to figure out.

I was thinking about it. If I have to scrap the barrel I might have to build another little monster and give him a cannon to play with. :madsmile:

Here's a pic of a trophy I made for my car club. Junior is unfinished in this pic. I made a trophy to put in his hand after I shot this pic. Anyway, I could build his twin brother and have him playing with a piece of the barrel.

https://www.milsurps.com/images/impo...1869865_-1.jpg

You do some great work, feets!

I understand the challenge of making something work. It's a battle of man against machine, and I appreciate that challenge more than most, and won't give up until it's a lost cause. I'd do as you just described to try to fight the battle and try everything to get it running, just for the challenge of it but I would not spend the money for a new barrel.
If it was a USGI carbine I would do so just to keep a part of history alive, but not a commercial clone.

You have the carbine bug already whether you know it or not, and you're hooked by the history of it's design.

Keep your project and please consider saving for a USGI carbine. You have love for machinery and when you have a vintage M1 carbine in your hands everything changes -
There is nothing like a vintage WWII firearm that comes alive as they do. It's 'living history' like nothing else in the world to possess a well made firearm from WWII that functions better than most guns made today.

After 65 years, nobody manufactured a carbine replica that touches an original mechanically and they didn't make one after WWII ended. An original USGI M1 carbine is worth spending a few dollars more for on mechanical merits alone.

When you have a piece of history in your hands that's most likely fought through two and possibly three wars because nothing else could replace it, you become to hold it in reverend as not only a tool but something with a life of it's own.

Feets,

You must have good sense if you replaced that MOPAR engine with a Chevy.....LOL

Rusty, your funny.....Frank

Quote:

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Originally Posted by Rustship

Feets,

You must have good sense if you replaced that MOPAR engine with a Chevy.....LOL

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I like a challenge but I'm not interested in throwing away good parts in exchange for lower performing items.

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.


Back to the carbine....

I went to the range today with my friend. We had a good time sighting in his new Remington 308 bolt gun. I also ran the 1954 Marlin Model 88 until the firing pin broke. I put all 30+ rounds inside the 9 ring at 50 yards. I'll have to scrounge up more parts to make dad's old rifle run again.
When I pulled out the carbine, tragedy struck. I left it's ammo at the house. :banghead:

No biggie. The new parts will be here in a couple days. I'll have to put it together with the new stuff and try again.

hmmm.... Midway USA has Criterion carbine barrels on closeout for $147. :dancingbanana:

***update***

The new parts arrived today. I took the carbine down and locked the barrel into my shop vise. The piston nut refused to budge. I ended up welding the piston to the nut which is a real trick considering the wall of the nut is tiny and you don't want it welded to the receiver. Once that was done I welded a 1/4 x 20 nut to the end of the piston. A 7/16" wrench spun it off but it didn't come easy.
I stuck the bore scope down the pipe and shot some brake cleaner into the gas port. There was a slight dribble into the chamber. I pulled out a .0625" drill bit and started cleaning the port. I was pulling out all kinds of nasty stuff. I was watching through the bore scope while turning the bit. I didn't want to hit the far side of the bore with the bit. That's when I broke through into the bore. Oopsie! I now have two gas ports. I guess it's a good thing the Criterion barrel is on it's way. the two holes are about 20 degrees apart. the new port is straight. The old port is off to the side.
I went ahead and cleaned up the gas cylinder. It was ugly in there. various bore cleaners were not doing the trick. I ended up using a foaming bore gel on a low speed Dremel buffing wheel. The piston now fits in the hole but it is tight. It will not pass the tilt test. Sometimes it's hard to pull rearward with my fingers. I'll keep working with it.

So, now that the gas port is officially too large, what's going to happen? Will it slam the bolt through the back of the receiver and into my forehead?
Who wants to pull the trigger first and find out what happens? :madsmile:

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.

Quote:

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Originally Posted by feets

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.

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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.

Quote:

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Originally Posted by 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.

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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. https://www.milsurps.com/images/impo...nlovegif-1.jpg
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...

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.

https://www.milsurps.com/images/impo...moneypit-1.jpg

JMHO :)
~ Harlan

I agree, spend your money wisely.

Phew - those commercial carbines sure are a pain. :banghead:

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.

https://www.milsurps.com/images/impo...212256_9-1.jpg

The Inland has a nice radius to the breech.

https://www.milsurps.com/images/impo...212256_9-1.jpg

Same goes with the Criterion.

https://www.milsurps.com/images/impo...212256_9-1.jpg

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.

Still too short for a respectable Tomato Stake!

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Originally Posted by feets

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

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We are all here to learn. Please continue.

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Originally Posted by cafdfw

We are all here to learn. Please continue.

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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.

First I would get a book that would inform me of the proper name of the parts you have in question. IE barrel clamp=barrel band.

For $20 give or take, you can but U.S. M1 Carbines, Wartime Production by Craig Riesch. It will show all the parts of a GI carbine with names and discriptions. If you are looking for something on an aftermarket gun I don't know what too say except look at book tables at a show. I think Auto Ordanance is the only current maker.

True. I used the wrong term. Instead of going back and correcting it I left it alone.

Is there one band that is preferred over another? I really don't care to have a pig sticker (oops, bayonet) on the end of my shootin iron. There had to be some reason they changed styles. Does anyone know what that reason might be?

Big dollars for original type 1 or type 2 bands. Surplus type 3 GI (bayonet mount) around $15/$18.

Type 3's are the best. Exercise your hacksaw to cut off the lug if you are a pig hugger. 8Q

I actually believe that the Type III bands help with the carbine's accuracy. The band is one of two points where the carbine contacts the stock. I believe the extension on the Type III band also helps with e barrel harmonics. My experience mirrors the article posted on CMP.

http://www.odcmp.com/Sales/pdfs/CMP_...Notes_2007.pdf

I do not own a bayonet (i might decide to get ONE just to have one) so I don't care if i have the lug on the carbine or not. I just want my shooter carbines to hit what I am aiming at (I hate the idea of empty soda cans not having .30 cal holes poked in them).

Thanks! I printed that pdf and will add it to my carbine notes.

My band is a commercial copy of a type 3 band. I guess I'll have to make it work instead of paying someone to buy another one just like it.

I'm not a pig hugger by any means. I likes me some bacon! I might use the carbine to put some on the table.

I don't know of any books, other than a section in WAR BABY COMES HOME but there's a ton of info on this site about all of the commercial carbines -

M1CarbinesInc.com

It's owned and operated by one of our members and he's done an incredible amount of research to put this great site together.

I have been all over that site. It helped me steer towards a Plainfield or IJ on the commercial side of things. I had no idea it was done by a member here but that sure makes sense.

Just curious - why did you decide to remove the skirt from the new Criterion barrel? - Bob

The IJ and Plainfield receivers are not cut to accept the skirt. It's incorporated into the receiver. It pained me to cut a brand new barrel but it had to be done.

There's not a lot of people spending money to upgrade IJ's so the aftermarket companies haven't made barrels for them.

I hope it indexes properly. Regardless it's yours now for sure. Good luck!

It should index properly. I took lots of measurements from both barrels and the receiver before cutting. I trimmed enough of the skirt to turn the barrel into the receiver one revolution and measured the results. A couple different web sites offer services to rebarrel the carbines with a mention of having to remove the skirt for Plainfield receivers. They also caution against attempting to do work on Universals.
As it sits, I've nearly got it screwed in fully. it's less than 10 degrees off. Before I remove any more metal, I'll pull the barrel again and clean the threads once more to be sure there are no chips or gritty bits interfering with the threads.

Feets, looks like you have a good detailed comprehension of how to maximize your project gun. I am really curious as how this is going to turn out.

No one here will ever have any doubt about your machinist and gunsmithing skills :thup:

(its your sanity that is in question!) :madsmile:

Appreciating my skills my be over stepping a wee bit. Recognizing my stubbornness may be more appropriate. :lol:

My sanity has never been in question. I have no sanity and there have never been any questions about that. :madsmile: