Mauser sporter with excessive headspace - what to do?

[mgmorden]

I've got a La Coruna Mauser in my safe that I'd had some pierced primers with factory ammo. Stuck it aside for probably 3 years now but I finally got around to getting a headspace gauge set and it closes (albeit tightly) on the Field gauge.

It's otherwise a nicely done sporter - aftermarket wood monte carlo stock, bent bolt, professionally drilled/tapped, reblued, etc. Not a bubba job. I don't want the rifle to go to waste, but I also want to be reasonable with investing funds with it.

I suppose the ideal situation would be to have a gunsmith just set back the existing barrel to correct the headspace, but I don't know how expensive that might be.

Potential other options:

1. Rebarrel with a used military barrel.
2. Rebarrel with something completely different. I suppose I could convert it to a 6.5x55 or something, though I kinda like the ballistics of the 8x57 round.
3. Have it reamed out to 8mm-06. I already handload so this isn't TOO bad but I like correctly headstamped brass so that's a difficult proposition (and I'd definitely need to figure the cost of dies into the equation).

Any suggestions?

Thanks.

 

[Jim Watson]

Do a Guffey, gauge everything.

I would consider semi-catting it.
1. Check for setback of bolt locking lugs and receiver locking abutments.
If the gun is just sloppy and not battered, then...
2. Neck 8mm brass up, then down with shoulder formed to fill the chamber.

 

[4v50 Gary]

If the first gunsmith created excessive headspace, he should fix it for you.

Cut the barrel shank shorter and then relieve the shoulder to re-establish the barrel shank length. Then ream it out again.

Had to do it one Mauser barrel. It isn't hard, but laborious.

BTW, last week I rechambered a 222 bbl to 223. It closed on the Go but not on the No-Go. Disassembled and polished the chamber this week, re-checked headspace and test fired it yesterday.

 

[mgmorden]

If the first gunsmith created excessive headspace, he should fix it for you.

I wish that were the case, but this is one that I picked up with the condition pre-existing. I've had the gun for a good long while (probably 6-7 years now) and have only put 3-4 rounds through it as of a few years back. When I had the pierced primers I didn't want to shoot it any further until I could determine what was wrong and just recently got around to checking the headspace.

 

[dh1633pm]

You have more than a few options. If the bore is in good condition you could just have it fixed. Why introduce a new caliber into the mix. Other options would include another barrel. If so, there are a lot of options since a good number of cartridges have the same base dimension.

 

[4v50 Gary]

Spend the money. Take Machine Shop I & II at TSJC's NRA Summer gonnesmithing school. By week two, you will be shortening the shank, setting the shoulder back and mebbe cutting a bit of thread on that shank. It will be a good learning experience that can serve you a lifetime.

 

[Edarnold]

Pierced primers does not equal excessive headspace. Have you checked the contour of the firing pin, and the protrusion from the bolt face? Also, what factory supplied the ammunition you had trouble with? Were the primers very flattened, any extrusion around the firing pin indentation? I would be checking these factors before dropping major cash on working over or replacing the barrel. To me, pierced primers are a sign of a too thin or brittle primer cup, a sharp firing pin tip, or excessive pressures.

 

[rcmodel]

What he said.

Pierced primers has nothing to do with excess headspace.

You have bigger fish to fry before worrying about the headspace.

1. Over pressure reloads?
2. Primers crushed and flattened during reloading?
3. Eroded firing pin tip from pierced primers before you got it?
4. Corroded firing pin tip from old WWII ammo and no cleaning?
5. Excess firing pin speed from an Extra Power firing pin spring when the gun was sporterized?
6. Replacement FP with excess FP protrusion??

Many other more likely things wrong to check besides excess headspace!!

That is not your rifles problem.

Excess headspace will manifest itself with backed out primers on low pressure loads.
Or, stretched and/or, cracked brass on high pressure loads.

But neither will cause pierced primers.

rc

 

[mgmorden]

Hmm. I had always just assumed that excessive headspace would cause more pressure and that might cause the issue.

The ammo in question was factory 8mm Mauser. "Hotshot" brand which I believe is the same as the old Igman ammo. I'm pretty sure that the spring is original, but not sure.

To tell the truth I may just order a new factory weight spring in my next order from Midway.

I'll check the firing pin too. To tell the truth I may have an extra of those floating around (I'm down to 3 Mausers now but have had as many as 5 at one time - I got lots of odds and ends parts laying around).

 

[rcmodel]

factory 8mm Mauser. "Hotshot" brand

Well, there's your problem!!!

I've never heard of "Hotshot" brand ammo, and until proven otherwise, I would assume it's some small companies reloads from the 1950's or 1960's.

1. Inspect the firing pin tip for erosion or pitting.
2. Buy a name brand box of ammo and try it again.
3. Excess headspace would not cause more pressure, but less, because the case would stretch further, get longer, and increase case capacity.
4. Which would lower the pressure.

Don't start swapping firing pins.
Because even though they are all the same?

They are not all the same!!

Most will require at least minor if not major safety flange fitting, protrusion check, Etc.

And if someone who didn't know that in 1960 did it??

That right there might be your problem.

rc

 

[Jim K]

First, pierced primers are not caused by excess headspace or high pressure. Barring a firing pin that comes to a point, pierced primers are the result of a light firing pin blow. When the firing pin strike is too light, the internal pressure pushes the firing pin back and primer metal is pushed back into the firing pin hole. Eventually, enough of those small bits of brass will build up inside the bolt that they block the firing pin.

Now to the headspace question. If the bolt closes with some difficulty on the field gauge, the headspace is not excessive. What you need to do depends on how much you plan to use that rifle. Spanish rifles, even the ones with Model 98 actions, tend to be soft, and I would stick to U.S. 8mm ammunition, or that level handloads. I would not waste time or money on it if I planned to use high pressure ammo or convert it to a higher pressure cartridge, as eventually the headspace will become excessive. Moderate loads will be OK for medium game hunting.

Jim

 

[HankC]

Throat too tight or too short can increase the chamber pressure and pop the primer at firing pin hole as well. One SKS vendor who sell modified SKS firing pin with firing pin spring is known to open up the throat to decrease chamber pressure as a fix to pierced primer. Personally, I think it is more due to the added firing pin spring that decrease firing pin support to primer, but opening up the throat seems like fix the pierced primers on these SKS.
"Hotshot" is Century import brand name.

 

[osprey176]

I traded a 98 action to a bud that, when assembled, pierced primers. The firing pin hole in the bolt face was eroded, and oversize. He drilled it and made and fitted a bushing that fit the firing pin correctly. Problem solved. Might be worth looking into along with the other suggestions above.

 

[redneck]

I would question the hot shot ammo as well. I bought a couple boxes of it in .243win when ammo was hard to find. I tried shooting it in a savage 110 and found it very difficult to close the bolt. The first couple rounds took more force than normal but not enough to cause concern, and they shot fine. About the 4th or 5th one I tried, it was very difficult to close the bolt and I decided not to shoot the rest. The bolt closes easily on all other factory ammo I have tried in it.