M14 Forum

m1jerm

So, got my big 5 M1 Carbine over to a local gunshop for them to look it over. Good news, mag locks up nice, everything is functioning, probably won't blow up in my face.
Bad news, guy at the shop says that the discoloration of the spent cases he is seeing from fired rounds means the barrel is pretty worn, throat erosion I assume. Probably last me another 5,000 rounds.

Also, I am having a devil of a time getting the rear sight removed. It looks like it was never mounted in there proper when they put the adjustable job on it and all my whacking with hammer and dowel does not seem to be budging it. I need to get some pics up of it, things look strange where the back of the thing meets the reciever, I have not seen contact like this on other m1 carbines.

That said, the above does not seem too horrible. Has anyone had thiers rebarreled lately? If so, where did you pick up the replacement? Prices?

Depth Afield

Going to skip right over asking why you'd remove it and get right to this:
Many times the rear sights were staked in place. Also, make certain you are moving it in the correct direction. Do not expect a dowel to last long. I have a copper bar that I use when drifting the rears. A staked carbine will laugh at a wooden dowel (if that is in fact what you are using).

garandguy10

Ok, I will ask. Why are you trying to remove the right sight asssembly?

m1jerm

Apparently, inquiring minds want to know so...
when I first got the rifle, it looked like the rear sight had never been properly installed in the first place. Though, what I suspect is, someone had driven it out partially (from left to right) to see the maker's mark underneath the back of the sight (its an adjustable one) on the reciever.
Now, its sticking halfway out of the dovetail on the right side.
Did some field work, went to a gunshow and looked at some pristine ones with the sights properly installed so I know what it should look like. Mines just not right.
Another odd thing is, there is a small bit of metal under the rear of the sight, it is actually contacting the receiver, right where the maker's mark is, and this is probalby why it was driven out in the first place. The receiver seems fine, but I have not seen this contact between sight and reciever on any other examples at teh gun show. I definitely need to put up pics to better explain the situation. Long story short, it either needs to go in, come out, or be replaced , which is what I am really thinking should happen at this point since that point of contact looks so wierd.

Albud3

If the 'discoloration' of the cases is mainly soot, that's normal for a carbine. Especially if you're shooting Aquilla, Wolf and some other imported ammo due to the lower pressure than normal upon firing. If the pressure is low, the brass will not expand enough to provide a good seal and the gases will flow back and discolor the brass. Even normal pressure ammo will leave some soot due to the 'straight wall' Carbine case. It doesn't have the shoulder to act as a seal upon combustion of the powder. The heat from firing also discolors the brass, so it all sounds normal to me. You'd have to take it to a gunsmith who has the right gauges to see if either throat or muzzle erosion is excessive enough to warrant barrel replacement. It sounds to me as the guy at the gun store is either unfamiliar with the Carbine or doesn't know what he's talking about.

M-1 Carbine barrels are for sale from the CMP (www.estore.odcmp.com), Brownells (www.brownells.com), Numrich (www.e-gunparts.com) and many other sources. Prices should run around $190. As for having the work done, I would send it to Tim Shuff (www.shuffsparkerizing.com) as he does it for $75 and his turnaround time is less than 5 days. He's done work for some friends and it is some of the best I've seen and at a very good price.

A very strong suggestion: go to the CMP forums (www.forums.thecmp.org) and ask your questions there. Many forum members are affiliated with the Carbine Club and you will not find more knowledgeable people anywhere on the Carbine. They can even help with taking the rear sight off.

Orlando

I would look for another gunsmith, as already stated shoot on straight walled carbine case is completely normal
If it shoots fine why would you even consider replacing the barrel? You need to remember M1 carbines arent match rifles
Rear sight move from left to right. There is a tool made for this

Depth Afield

This.

Carbines for all intents and purposes lack a throat. No idea what kind of wear your hack armorer is talking about.

m1jerm

To be clear, the discoloration is that the back of the shell casing is LIGHTER, not darker than the fore end. It looks as if the shell has had to expand slightly, causing the brass to brighten. Which would stand to reason if the throat is worn.
I am looking into a more experienced gunsmith, and I do need to take it out to see what kind of groups it can hold, but it really sounds like I need to get a proper gauge on the throat more than anything.
Pictures forthcoming once I get home from work, can't goof off all day here.

Orlando

You are worrying about nothing. The rest of the barrel will wear out before the throat on a carbine

Gus Fisher

Could not agree more. There never was a G.I. throat erosion gage for the M1 carbine like there are for the 03, M1, M14 and M16 rifles. They don't wear out the TE because the .30 cal carbine round is basically a pistol round, not a high power rifle round. I was fortunate to get a really nice commercial TE gage from Tony at Orion 7 years ago and have gaged many dozens of carbines for TE. Even on the worst worn Korean Carbines, I have never seen a TE reading that went much over "3" and none that ever had a worn out TE before the barrel had LONG SINCE been toast.

For M1jerm

Are you sure the gunsmith said something about TE and not Headspace? If it was a headspace problem, that could require a replacement barrel.

It also sounds like they used a shim to tighten up a loose rear sight.

It was not uncommon for the adjustable rear sight to be staked in place so the center reading line on the rear sight was centered for the windage of the rifle. That gives you more actual windage adjustment when the wind comes up. That sometimes puts the RS over towards the left or right side.

Albud3

I went and pulled some fired cases from my carbine to check what you said. As yours also shows, the case is brighter towards the rear where the web of the case is. This is normal as the thin walled case body expands while the web (which is solid) doesn't. This results in the discoloration of the forward case while the rear stays fairly bright.

A quick and easy test to see if you might have a headspace problem is to take a paperclip, straighten it out, make a small 90 degree bend, file the end to a point and run it up and down the inside of the case. If you feel a definite 'catch' down near the web, you might have a headspace problem as an excess allows the brass to 'flow' forward thinning the brass at the web that may lead to a case separation.

Do have the gun checked out by a good gunsmith that has the needed tools and knowledge to do the job correctly. Be sure he knows how to dis-and reassemble the bolt as this has brought grief to many carbine owners!

m1jerm

What explains the problem better than words, crappy photos! Camera focuses on everything but the thing I aim at. Hopefully captions will help.

1. shell case. I think you can see the definite marking near the rear of the shell, its brighter and while I have not check it with calipers, I wonder if the shell has not expanded somewhat.

2. overhead of sight. Its halfway out on the right side. Windage has been adjusted all the way to the left, but you will notice that there are 2 points, almost nipples that actually stick out from the metal plane that mounts into the dovetail. It does not look it could actully fit back in there even if I did try to drive it back in. Weird.

3. back of the sight, you can see that the sight touches the reciever here, there is no daylight between it and the top of the receiver. This was not the case in others I had seen.

So, any thoughts? Perhaps I can get better shots in the daylight this weekend, can't get any sunlight in the evenings when I get home and my lousy indoor lighting is obviously not helping.

Attached Images

	shell.jpg (10.4 KB, 38 views)
	sight1.jpg (17.3 KB, 34 views)
	sight2.jpg (22.5 KB, 33 views)

Sustinemus

There is probably a button on your camera that looks like a little flower or tulip. That is the symbol for "macro" and will allow you to take focused closeups.

m1jerm

Okay, tried it again, perhaps these are a bit clearer.
So the shell case definitely has marks toward the rear. The shop guy never said anything about throat erosion, that was simply my uninformed guess. What he said was that this indicated that the barrel was worn to a point where eventually the shell was going to start splitting. It was simply worn to a point where this would happen within about 5 thousand rounds. I have no idea how many of these he has seen.
As for the sight, you can see that the small extenstion under it fully contacts the receiver, which just seems odd.
Also, the two protrusions on the plane that engages the dove tail are more visible. I just get the feeling that something is wrong there at the reciever and maybe I need a new sight. Its halfway out as it is (that's how it cam to me).

Attached Images

	shell2.jpg (26.5 KB, 20 views)
	sight1a.jpg (13.8 KB, 16 views)
	sight2a.jpg (19.3 KB, 20 views)
	sight3.jpg (20.0 KB, 20 views)

captain_bob_badfish

The rear site has been moved as you suspected. There is a tool you can get to put it back into position. Since it is no longer staked you may want to ad some lok-tite to it to keep it from moving. Also the tab on the back of the sight that touched the receiver is normal. I have some that touch, and some that don't. Not a big deal.

You also mention that the bbl only has 5k rounds left in it's life? If so, thats sounds real good to me. The bbl would not be an issue for me. I'd be surprised if you shoot it 5k times during your lifetime.

Shoot it... and enjoy it.