Is this possibly a head space issue?

[Jaxson50]

I took my recently acquired US Model 1917 to the range last week, shooting commercial 180 gr. loads the recoil was pronounced enough that the range master commented on it.
After about 12 rounds it became difficult to pull the bolt back, it rotated well, but after three more rounds it wouldn’t pull back at all. The range master used a rubber mallet to tap it open.
I was slow firing so I don’t believe it was a heat issue. The shells extracted correctly.
I inspected the primers and it did seem they had rounded off, in other words the fired primers were no longer flat but rounded a bit.
After returning home I cleaned it well, the bolt cycles well now, but there was a considerable amount of black caked of goop in the action where the bolt lugs rotate.
To be clear, I have fired more than a few .30 caliber and larger rifles, I’m not a stranger to recoil, my standard range rifle is a M1A.
The recoil was more what I would expect from a 45 70.
Does this sound like a head space issue?

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[Patrick Chadwick]

After returning home I cleaned it well, the bolt cycles well now, but there was a considerable amount of black caked of goop in the action where the bolt lugs rotate.

My guess: the only place that "black goop" material can come from is from the cartridge case itself, in the form of incompletely burnt powder.

Since the case neck normally obturates to seal against the chamber, one has the nasty suspicion that this is precisely what is not happening.

This effect may appear with underloaded ammo that does not provide enough "bang" to expand the neck sufficiently. But you say that you used commercial ammo, so we are left with the worrying possibility that the neck area of the chamber is too large. In which case, the barrel is kaputt, KO, scrap, whatever you like to call it, but NBG for shooting.

When you bought the rifle, was it specifically sold as being chambered in 30-06? In the past, some very peculiar things have happened, such as old 30-06s being reamed out to take 8mm Mauser or wildcat chamberings.

A chamber cast seems to be advisable here. Maybe the rifle is no longer chambered in 30-06.

[mmppres]

I am also in the mind set that you need to get a chamber case done. Were there any other sign on the fired cases. Rings splits etc?

[rcathey]

Did you clean any oil/grease out of the chamber that may have been present? A lubricated chamber would increase bolt thrust.

[Patrick Chadwick]

Before making a chamber casting, the simplest thing to do would be to measure a fired case, and compare the results with the SAAMI or CIP standards. A chamber casting can be very problematical if the chamber has a ring (from overpressure or scoured-out rust) as it is then very difficult or even impossible to extract the casting !

A properly obturated case will be a couple of thousandths smaller than the SAAMI/CIP chamber dimensions, but never larger. If, for instance, the neck on a fired case is wider than the maximum chamber dimension, then the chamber is no longer correct for 30-06.

[us019255]

Before making a chamber casting, the simplest thing to do would be to measure a fired case,

I like that advice. I never thought of that, even though I was suspecting a chamber problem. I learn a lot from this forum! I hope Jaxon50 finds out what is going on.

[browningautorifle]

measure a fired case

How about a picture of one here? It should be obvious...if there's something amiss.

[Jaxson50]

Thanks for the suggestions, I will follow up on them asap, and post what I learn here.
A couple of notes, the barrel is original, date stamps indicate Sept. 1918. The serial number indicates the receiver was made in October 1918.
Before firing I cleaned the bore and chamber.
The problem wasn't that the brass was stuck, it was the bolt itself. It rotated fine, but wouldn't draw back. As soon as it was tapped it would draw back and the brass extracted without any problems.
I was shooting Federal Power Shock 180 grain bullets. I saved all the brass, looking at them now I see very minor scratches on a few, the finish is bright from the rim up about 1/4 inch, then they aren't dull. I can find not signs of cracking, splitting or excessive widening of the throat.
The unfired primers aren't rounded a bit, but the primers on the fired brass are flat, like they were flattened against the bolt face.

[Ridolpho]

Jaxson50: You didn't say anything about the general condition of the gun. How does a bullet seem to fit at the muzzle? Have someone shine a light from the muzzle and try to eyeball the chamber area from the rear- is it clean and rust free? Was the gun completely cleaned of any storage grease crappola- I'm always amazed at how much of this stuff I find in the locking shoulder/ extractor cutout area of some rifles that I know have been shot by previous owners. What you describe almost sounds like more gunk than a few rounds of quality ammo can generate from gas leakage. As BAR suggests- try to post some photos.


Ridolpho

[Jaxson50]

Sorry I haven't posted pics. I have tried but had problems as I'm using a tablet I guess.
I did cover a bullet with a magic marker ink and cycled the shell, it left two light impressions from lands on the bullet half water between the tip and the shoulder of the bullet.
The weapon itself is in excellent condition, certainly worth fixing.