Possible headspace problem?
Hi folks-
I am looking at several old rifles on the auction side and have a question about a photo that a seller sent me. It is a 9x56 Mannlicher and the ammo and brass is part of the auction.
This is a box of shells loaded by Buffalo Arms in Idaho. I have bought loaded ammo from them in the past and found it to be very consistant over a chronograph, so I do think that they put out a good product.
In the photo, it looks to me like most (not all) of the primers have backed out on the fired rounds. So the question is - would you be wary of buying the rifle that fired them?
I am looking for an old rifle to do some target shooting and a little hunting, so it is not something that I would be shooting thousands of rounds from.
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I am looking at several old rifles on the auction side and have a question about a photo that a seller sent me. It is a 9x56 Mannlicher and the ammo and brass is part of the auction.
This is a box of shells loaded by Buffalo Arms in Idaho. I have bought loaded ammo from them in the past and found it to be very consistant over a chronograph, so I do think that they put out a good product.
In the photo, it looks to me like most (not all) of the primers have backed out on the fired rounds. So the question is - would you be wary of buying the rifle that fired them?
I am looking for an old rifle to do some target shooting and a little hunting, so it is not something that I would be shooting thousands of rounds from.
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what is the rifle and caliber?? i do not like the looks of the pic 0 -
1fisher,
The protruding primers is usually a sign of low pressure loads.
"There were protruding primers on some of the fired rounds. When the firing pin hits the primer, it pushes the primer and the new case forward in the chamber. When ignition occurs, the pressure expands the walls of the brass. The rough chamber, with its high friction, grabs the case at the forward position and the gas pressure first pushes the primer back against the bolt face. As the pressure builds, the brass case is stretched until the case head is pushed back against the bolt or the case supports the total load. If the case head is pushed against the bolt face, it would produce a flat primer, but flush. If the load is light, the case does not stretch so much and leaves a gap between the case head and the bolt face, but the primer is still against the bolt face. This produces the protruding primers."
Best.0 -
I would attempt to contact other owners of M-S rifles to see if the have similar experience's with protruding primers after firing. Since the M-S has a two piece bolt with a removable bolt head, there is always potential for a certain amount of setback depending on original manufacturing tolerances, and the round count that has gone down the tube. A original M-S in 9 X 56 is probably at least 50 years old, no telling how much it's been fired and what kind of loads it's seen over the years. 0 -
I agree that this could be from low pressure. It is very possible that Buffalo Arms is being cautious in their load and this is the result.
I am just a little leery because of my good experiences with their product in the past. They seem to be pretty good at duplicating the original loads for old calibers.0 -
Are these head stamps I see "LC"???? Is that reformed ammo he shows???
What gun is this in exactly?? I have several OLD 8x50 and 8x56 MS's and they do Not protrude primers. As posted...the two piece bolt head affects the headspace and there was many of them changed over the years. bob0 -
Bob-
Yes, this is reformed brass. The more I think about it, that may be the source of the problem. I wish that I could reload one of those fired cases to see if fire-forming the brass would eliminate the issue.
This is from a model 1905 Mannlicher Schoenauer.0 -
Yes, the headspace is probably at least .010 greater than desirable for those reformed cartridges. BUT, it's academic since once you fireform the brass to your chamber and set your FL die to where the shoulder should be, headspace will be corrected to your chamber dimensions.
Without a headspace gage, you can't tell if either the ammo shoulder or chamber shoulder is in the right place.0 -
Ok.. with that reformed brass, another train of thought comes to mind.
LC brass HAD the primers crimped in, perhaps the pockets have been
"cleaned" up too much. bob0 -
No. If the case properly fit the chamber there would be no room for the primer to back out on firing.
You could contact the ammo manufacturer, tell them the problem and ask what standard they set the shoulder to.0
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