I am posting this for my father so forgive my lack of knowledge on this rifle.

TLDR- Had a ruptured case on a 1903 and cant figure out why.

This 1903 was purchased at auction. Upon taking possession of this rifle, it was discovered that somehow there was a stuck case in the chamber from previous owner. It was taken to a gunsmith where he removed it, and informed my father that it appeared to be a ruptured case and everything appeared to be in working order and "safe". So, a couple of days ago, after replacing some stamped parts on the rifle with some correct milled parts, my father wanted to take it out and shoot it for the first time. He manages to get the first round off but the bolt took some serious force to unlock. Once it did unlock, He had to use again, some serious force to bring the bolt to the rear to eject the spent case. the picture below is what that case looked like and I presume is why it was stuck. so now it has gone 2/2 for ruptured cases. For safety reasons, we thought it would be a good idea not to try to fire another round.

My google fu is weak and I couldn't find anything past the poor heat treatment of the receivers causing issues. So, what could be the potential cause of this? Headspace? FUBAR barrel/chamber? wrong ammo? Thank you in advance for any information you guys might be able to provide.

The gunsmith didn’t check headspace?

My first order of business would be to order a field gauge.

Check headspace for sure.

But also take a look at the chamber to make sure it’s ok and corrosive primers haven’t taken their toll.

While you’re at it, take a look at the barrel.

FWIW, the issue ought to have been disclosed in the auction write up. Might want to consider causing a fuss and/or returning the rifle.

From what my father has said, it was. But the gunsmith said it was on the verge of failing the gauge. The gunsmith said he would have to use hand loads for proper function. That was disclosed to me after the fact. But Is that common practice to recommend hand loads on a worn barrel? I would think a barrel is either g2g or it is not.

I'll take a good look at the barrel again but when we checked for obstructions before firing it looked okay. Unfortunately, the rifle was sold as is, so I don't think a return or raising a stink is an option.

That rupture isn't where a failure due to headspace would occur. A good borescope of the chamber and a casting of it is the minimum that needs to be done and an inspection of the area around the chamber for a possible crack needs to be done also. A thorough check for any welding needs to be done.

What happens if you cycle a round without firing?  Any marks on the brass?

Only marking on the case is a slight scratch from where it left the follower.

Just brought that up to my Dad. He said the gunsmith said it looked like it had been welded. Interesting. Is the only route to go from there pretty much a full barrel replacement?

I would replace the barrel?  Was any welding done to the receiver?

Ok, that helps.  Was wondering if there was a burr in the chamber that was causing a local stress riser.   I've seen 30-06 cases rupture like that before but usually in reloaded brass or in some former linked machine gun ammo that was delinked.   The comment about welding in the chamber is interesting..can't imagine why that would be the case unless at one point this was a drill rifle, but think those usually have a plug or something else welded in that can't easily be removed and put back into service.

I'd say a barrel swap is the safest thing to do.   Looks like a nice 1903 from what i can see in the pictures.   Hope you guys get it worked out!

Is this a reclaimed drill rifle, by any chance?  There's no telling what was done to it on either side of it being made into, or reclaimed from, being a drill rifle.

If at all possible, take this to a competent gunsmith and make sure they have a credential.

If you have or can borrow a borescope, that chamber is easy to access and should show any irregularities or defects.

Was the case that was found stuck in there the first time, similar to this one? I’m thinking the first gunsmith didn’t take a chamber casting?

There is more to the chamber than just the shoulder datum, especially in an antique that was found with a stuck case. The root cause of that initial stuck case begs the question of the integrity of the whole chamber and bore, not just the headspace.

Whoever sold you a rifle with a stuck case in the chamber was incompetent if they didn’t disclose that fact.

What is the date on the barrel?

Armourers had sanding sticks to remove rust from the chambers, I had a 1943 03-A3 that would bulge the fired cases on one side of the case. And I think the chamber had been sanded to remove some rust.

You could also have defective ammunition that caused the case to split and rupture.

I have had many old worn milsurp rifles and simply reloaded reduced loads to put less strain on the rifle and brass.

I would test fire another brand of ammunition and see if the case ruptures, this would tell you if you have defective ammo or a oversized chamber.

I downloaded my 30-06 ammo to around 2400 fps and used 30-30 bullets for hunting deer to keep the cases from bulging.

Can you take photos of the fired primers to see how flattened they are and if they are protruding from the base of the case.

Another thing you could do is use some foam bore cleaner in the bore and let it soak overnight. Keep doing this until it no longer turns blue and you no longer have copper in the bore.

Below a 1943 No.4 British .303 Enfield rifle with a frosted and pitted bore, and one shot of foam bore cleaner would remove 95% of copper in the bore. The reason I tell you this is the ammunition used in these older milsurps had corrosive primers. And if not cleaned properly it could cause pitting in the bore that quickly picked up copper that would buildup and restrict the bore diameter. When I first cleaned my 03-A3 I actually had copper chips come out of the barrel using a very aggressive copper bore cleaner. The foam bore cleaner simply cleans the bore without having to scrub the heck out of the bore with bore brushes. The frosted and pitted bores will "eat" the copper bore brushes and give you a false copper reading.



Below one application of foam bore cleaner in a AR15 and the patch after soaking for a few hours.

This - big time.

Thank you all for your replies. I will have my father take it to an accredited gunsmith. Once he does, I will update this post with his findings.

If I remember correctly I think he said 1917.

I think you nailed it.

Somebody probably welded up a drilled chamber.  This would explain the mid-side blow out (in a supported area, not expected).

You may get away with it (welding a chamber) for awhile, but sooner or later it will catch up to the shooter.

If that barrel had been subjected to the heat of welding, its strength may have been reduced to the point that the first round fired out of it caused it to yield (expand permanently). Any subsequent round is now being fired out of a chamber that is too large in diameter, and splitting.