Thanks for the suggestions. 

Run the ammo through by hand and see if you can identify certain rounds that cause the problem. You can swap parts between your carbines to isolate the issue.

Head space might be just fine, but it’s the first thing that should be checked on any new, or new-to-me carbine. 

Failure to close would be if the casing is too long, or the headspace is too tight.

The field gage you have coming will indicate if there is too much headspace.

Maybe a drawing would help. Let me look.

I am going to pm you with the method to measure actual head space to rule that out right off the bat. I have had a carbine that had obviously been shot…a lot, but when I checked the action, it would not close on a go gauge. Previous shooters just had not came across that round that was 1.290 or longer…yet.

It could very well be your Inland eats it and the QH chokes. No two actions are usually exactly the same.

It is possible to maybe “set” the round deeper into the chamber after a couple of bolt-bangs.

This has me a bit curious…..was the round hard to extract, like it was sticking? Any unfired commercial or reload should not be hard to extract. Tight head space, out of spec brass or sticky chamber will cause that.

I was going to look for a digitized drawing or photo to mark up.

I thought I had seen one that was suitable.

Sorry I got delayed - had to deal with the seller of my Midway who thought my comment in his CMP feedback thread was unwarrented.   

With Floyd helping you make a check with the real thing, an illustration may not be needed.  

See how that goes. 

I was just reading this post, and remembered that I recently shot up a box of Aguilla. I saw the brass to reload, so went to the shop and pulled out a few pieces. Of the first two I measured, one was 1.280", the other 1.290". I'd say they're not too picky about case length.

Here's a picture I think will be helpful. 

http://www.uscarbinecal30.com/barrels.html" rel="nofollow">

http://www.uscarbinecal30.com/barrels.html" rel="nofollow - from http://www.uscarbinecal30.com/barrels.html

Headspace is the distance from the bolt face to the foward edge of the chamber.

If the cartridge case is too long, then the bolt may not be able to close.

For example if an agulia cartridge has a case 1.293" long, and the headspace is 1.291".

On the other hand if the chamber is a little short, then some cases that are within specification won't allow the bolt to close.

Extractor

painter777 has a great photo on milsurps forum showing the extractor and its plunger.

As the bolt closes on the cartridge, the extractor is pushed back on its spring loaded plunger.

http://www.milsurps.com/showthread.php?t=24758&p=136353&viewfull=1#post136353" rel="nofollow">

http://www.milsurps.com/showthread.php?t=24758&p=136353&viewfull=1#post136353" rel="nofollow - from https://www.milsurps.com/showthread.php?t=24758&p=136353&viewfull=1#post136353

There's an animation showing the extractor snapping over the rim at 4:16 in the training film  digitized and posted here. https://www.milsurps.com/showthread.php?t=17368&p=93030&viewfull=1#post93030" rel="nofollow - https://www.milsurps.com/showthread.php?t=17368&p=93030&viewfull=1#post93030

Are you saying it could be a burr on my extractor or an issue with the extractor?

I know you are gathering the stuff you need to make some measurements. Discovering what’s going on with head space and brass length will help us determine what’s going on here.

I think Wayne was inquisitive about the extractor as I was. If it is somehow not installed properly, it might interfere with closing by not jumping over the rim. If it can be manipulated freely with a punch or screwdriver….should be good. Jumping back off the rim as you tried to extract it can be caused by the round being driven into the chamber (tight head space). I know I sound like a broken record, but checking that is the first step.

You can measure your spring length. Anything down around .380 can be too weak and much above .420 could be too stiff. There could be some difference in the “feel”, but the test is, does it work and if it does, spring length won’t matter. Lets solve one problem at a time.😁

A slight aside.  I bought dummy rounds (aka snap caps) to cycle and dry fire practice (has a rubber primer).  After a number of cycles the bullets started to  get pulled out.  I noticed it first when they didn't easily load and unload from the magazine.  Being empty cartidges I just squeezed them back in with a vise.  Obviously or maybe not so obviously don't do that with a live round.

My points are that its not unusual for the bullet to get yanked a little when cycled without firing. 

And if you want rounds for cycling there are people out there selling dymmy rounds and snap caps.

The dummy rounds made for the US Military may be more durable ???? in terms of cycling without pulling apart.  

I had issues with the Aguila, and then Armscor. I thought it was all aquila, but then realized the other mag was loaded with armscor. After i noticed that ( I was out of the aguila), i looked through the remaining armscor rounds I had and sure enough, almost every single round has the bullet seated at different depths and the projectiles are 100% more round/fat than the military surplus I compared it against. The rabbit hole just keeps getting deeper for me. 

Something else that makes me think the firearm may have a bug in it is that my inland shoots the commercial ammo just fine. I am confident with all of your help I can get this figured out.

The bugs I had with my inland when I first got it were Failure to Feeds, and I was able to figure that one out on my own. This one is a new one to me. 

Shouldn’t matter.

You mentioned above what might could be done if in fact you have a head space issue. A couple of physical things and one maybe a mental thing.

Find a shorter bolt. That will get difficult finding a bolt with the correct makers mark and guessing if it will be shorter when you do. Obviously, you can get any primes bolt that will work and use it as a shooter. The correct Quality can be for looking it.

Have the chamber finish-reamed for your Quality bolt.

The mental option. Find and shoot ammo that you know it will shoot and never use any that you have not checked. Most commercial that I have checked will fall around 1.285-87. The outliers are surely out there. You can learn to measure the cases on unfired brass close enough to be comfortable with doing it.

So…there you go. A replacement bolt, a trip to a Smith (or friend) you can trust to touch-up the chamber, or just watch your ammo.

So you took something like this, (the fine grain tube in it) put it on a patch, put on a drill and scrubbed the chamber with it? 

This is uncharted territory for me, so I’m making sure I don’t do anything stupid. 

For good measure, I have my bolt soaking in hoppes tonight as I have my caliper coming tomorrow. 

I still probably wouldn’t do anything until I head space it though.

The field gauge is only going to tell you if the head space is too long. In this case, we are dealing with potential short head space, so not having the field gauge is no issue at this point.

OP has indicated issues with bolt rotation and extraction. The two issues are surely connected. I have had experience with this very problem. Be it a tight/fouled chamber, short head space or long ammo cases…..if the round is not fully seating in the chamber and offering a minimal amount of clearance between the bolt face and the cartridge base….extraction issues will follow. I think when head space issues are corrected, be it a chamber issue or bolt/cartridge length, the extraction issue will go away.

You can take the assembled bolt in your hand and test the operation of the extractor by hand with a piece of brass and have it function flawlessly. Shoot it in a gun and funny things you cannot see or detect take place.

I would think the bullet head coming out would be the rifling and not the chamber.

Recently someone had mentioned that the Winchester dummy rounds could leave the bullet head in the chamber.

There was also a discussion somewhere how the carbine .30 cal is not crimped, so there would be very little grab to retain the bullet head.

Dan,

Were you thinking of this thread http://www.uscarbinecal30.com/forum/my-1-9-mil-npm-from-mway-w-free-bullet_topic5543.html" rel="nofollow - My Midway...w/ free bullet ?

Redtail wrote "It wasn't in more than 3/4-1 inch in, just to the the rifling as you can see..."

By  1" was he was describing the chamber length?  That was what I  guessing.

The dummy bullets I mention there were recently made and sold on e-bay.  None show rifling impressions but did start to pull out over repeated use.

(The photo I posted later in the thread is a mystery bullet that was in my house growing up.  IIRC it was in an abelone shell along with matchbooks.  Not even sure its .30 carbine although it has 4 grooves so I think its likely.)

Since then I've received some 1943-44 WRA dummy cartridges with the tin coated bullets.    http://www.uscarbinecal30.com/forum/ammunition-types-historical_topic5767.html" rel="nofollow - http://www.uscarbinecal30.com/forum/ammunition-types-historical_topic5767.html

I have only cycled them through once.

You have both an envious situation yet perilous. As long as you don’t exceed normal brass lengths, no problem. Where you will possibly get into difficulty is out-of-spec brass or varying projectile shapes. It’s been documented that some chambers don’t like some profiles. A round longer than the action likes, or a profile that contacts the rifling could cause issues. You have pulled at least one bullet, which indicates the latter might be in play.

I have lost track whether this is a “correct” carbine or not. If it is original, I would clean it up, leave it alone and shoot my shooter. If it is a shooter, I’d find another bolt that was shorter for that just-in-case situation, or be forced to measure the ammo that I fired in it. A chamber can get a little grungy, a case can be out-of-spec or a bullet profile it doesn’t like can show up. You might find yourself looking at the bolt lugs to make sure it rotated. I have an SG that measures 1.291. It’s a shooter and I found a bolt that head spaces 1.293, which makes me more comfortable.

PS: I’d try to cancel the order for the field gauge, you won’t need it unless you plan to be evaluating carbines in the future for long head space.😁

The carbine is most certainly in spec. Some commercial ammo might not be.

If you think the chamber is clean and a spec round passes the plunk test and you don’t have sticky-extraction, I don’t think polishing is necessary.

Correct. See if it drops in and bottoms without forcing it. Maybe have to use a finger-nail to pull it out. I push on it to insure seating, but it should slide out easily.

Basically yes.

Take a look at the cutaway from the club's webpages I posted earlier.

This one.

The lower arrow points the end of the barrel.

The entire rim of the cartridge is outisde the barrel. 

The rim of the bolt  is shown touching the barrel face although I suspect that's a slight clearance fit or else the bolt wouldn't rotate in as easily as it does.

There maybe subtlties I'm missing.

I don’t think the rim is tapered that aggressively on the base in real-world ammo. Looked at that picture before and never noticed that.

On my inland, which shoots anything I give it, had both the Korean Surplus and Armscor seat and come out easily. (no surprise, have no issues at all with it anymore)

Moved on to my QH (one with the perceived "issues"), and the Korean seated and slid out with no pressure with my tweezers. 

Next, I plunked the Armscor in it. I had to squeeze and pull with my tweezers to get the Armscorp out of the chamber. IT WAS TIGHT.  So, I guess it really was the ammunition and how tight my chamber is. Very interesting results, but pleased that's all it is. Luckily I only have a few hundred rounds of armscor, which will be fed to my inland to conquer the turtles taking over my pond! 

what is the serial number range of the two carbines?

barrel dates if present

Inland has barrel date of 11-43 serial number is 3072253

OK, so the Inland would have the late chamber.

According to CCNL 334-3 we have seen in the serial range of 1875-1890 RO undated barrels, BA-9-43, Underwood 8-43 and RO 6-43

In another thread we were discussing the change in ammo case profile and chamber profile being changed in June of 1943.

http://www.uscarbinecal30.com/forum/may-1944-ammo-test_topic5731.html#45400" rel="nofollow - http://www.uscarbinecal30.com/forum/may-1944-ammo-test_topic5731.html#45400

Rockola stopped dating barrels in 6-43 and this may not be a coincidence.

I am wondering if your undated RO barrel may have been one of the first undated and somehow has the earlier profile which is causing the chamber to catch the later ammo a little but more?

Only real way to find out is to slug the barrel. I am sure others can explain how and where to get he metal to do so, if you were interested in doing it.

Basically I believe they found the later profile case should work in all carbines, but earlier cases would have malfunctions in later carbines.

Armscor would be of the later design….I assume. Just guessing here and assuming no commercial manufacturers were producing ammo at that time, thus all commercial ammo would be of the later design and should fit either chamber? I think this is a case of the Armscor bullet profile just not liking the chamber in this carbine. It being a very little-fired and fresh chamber, the crisp rifling in the throat is grabbing it. I bet after some firing and wear, won’t be a problem at all.

Any .30 carbine ammo made after the specification change should have been to new standards.

Ordnance was reaching out to all ammo manufacturers for propellant and primer types to fine tune the .30 carbine.

Fast forward to today, manufacturing has changed and are the commercial manufacturers holding tolerances or making their product "good enough?"

I would default to you on what ammo is better digested than other ammo companies

New2brass wrote: manufacturing has changed and are the commercial manufacturers holding tolerances or making their product "good enough?"

That's for sure. Armscor on the right. I personally have never had issues with it and it feeds and bangs in anything I shoot, but it's obvious the profile differs. I have noticed they seem to seat the bullets a little deeper, closer to 1.65-.66 on average.

Opps, missed that. Strange then, I've run 1000's of rounds of Armscor the past couple years (I found a deal on it before the current panic) and the only carbine it gave me issues with was my Plainfield before I swapped springs in the bolt

Matt, where do you find snap caps/ dummies for the carbine? Locally, or is there a dealer on line?

BTW, this was a great thread. It is amazing how much I have learned since I first posted this. Never thought I would know as much (but not even close to knowing half as much as most folks on this forum) as I do now though. Thanks Everyone!

What kind of a bullet is on the left? 

Hey Rebel 92: 

Have you put the calipers to live rounds measuring 1) at the very base of the cartridge, 2) at mid body of the cartridge then 3) at the mouth of the brass comparing your a) Evansville 1944, b) Korean 1972 (and any other MILSURP stuff) and c) the AMSCOR loads?

Further, have you looked to see if any of the rounds show rifling marks on the bullets after the plunk test?

I understand that may be a tedious time-consuming project but right now it's Miller Time and is an excellent excuse to pop-a-top on a few brewskies.

The vender I bought from on ebay is no longer listed.

I think probably a guy just making them on his own.

If you're hand loading I think the only trick is to find a suitable material for the primers.  Maybe go through McMaster-Carr looking at 1/4 inch? sheets of rubber as well if there is rubber extruded in the right diameter.  Might be easier to slice a dowel than punch the sheets.   Cyano-acrylate (sp?)  best known as Krazyglue ought to be a good adhesive for rubber to metal. 

Doing a little googling there is a business in Ariz  making .30 carbine dummy rounds with a rubber primer.

https://realisticsnapcaps.com/product-page/premium-brass-30-carbine-snap-caps-m1-carbine-dummy-rounds-5-pack/" rel="nofollow - https://realisticsnapcaps.com/product-page/premium-brass-30-carbine-snap-caps-m1-carbine-dummy-rounds-5-pack/

Thanks, got em ordered! So I can cycle these and they won’t pull apart?

Ethan, I have no experience with them, I just saw that you and Matt were discussing them and remembered seeing them on ebay. Hopefully they don't pull apart.

Home made snap cap:

Using a sized case:  Mix a small amount of epoxy glue or maybe some J-B Weld, then, using a cotton swab smear some inside the mouth of the brass, seat the bullet in the usual fashion.

Fill the primer pocket w/ silicone sealant; smooth flush w/ tip of finger.

Let the above 'set' or 'cure' and ya have a really inexpensive snap cap. 

Works for me!