I have a 98 mauser 8x57 that has a head space problem. When factory loads are fired the primers back out .0020 of an inch. There are no signs of pressure. According to the proofmarks this rifle was brought into Belgium and converted to a sporter there. Nothing fancy, but they did a nice job on it. I like the rifle and would like to rechamber it to something useful. Is 8mm06 about the only option without changing the barrel? Anyone know of a gunsmith that would have the 8mm06 reamer and would do a good job? I've read that Midway has 8x60 brass but it is close to obsolete. I guess either way I'm reloading. Is pulling the barrel, removing a few threads, and reaming the chamber back to 8x57 an option? What would rechambering or removing a few threads cost? Any other suggestions? Thanks in advance.
head space issue on a 98 mauser?
- Thread starter North of 58
- Start date
.002" (not .020), probably nothing to worry about.
Clean the chamber very well. Headspace can be checked with gauges. The barrel can be set back, real easy if sights are not a concern, more difficult if sights need to be aligned.
It could be an ammo issue also.
Clean the chamber very well. Headspace can be checked with gauges. The barrel can be set back, real easy if sights are not a concern, more difficult if sights need to be aligned.
It could be an ammo issue also.
gunrunner8
CGN Ultra frequent flyer
- Location
- Kamloops, B.C.
If primers back out .002" then headspacce is rather on tight side! If .020" then you have a problem, bigger if rifle has the open sites and less of a problem if the barrel is without them. In the last instance removind the barrel and trimming the face of tennon and barrel shoulder some .016"-.017" or so will fix the problem. I say it should cost you in the neiborhood $75-$100 or so. And stay with 8x57 there is nothing wrong with this cartridge.
Thanks for the replies. Sorry, it is .020 the primers back out. They stick out a noticeable amount. I tried shooting another brand of factory ammo when I saw that. Both Federal and Remington are the same. The rifle has iron sights that would have to be re-aligned if the barrel is set back. I have a few others in 8x57 so if it was rechambered to something different it would be okay.
If the rifle shoots well, think about reloading for it.
There could be other issues besides the chamber. Like the locking lugs setting back the lock up faces on the receiver. This happened once in a while to re heat treated receivers or late war receivers that weren't heat treated properly.
When many of these old war horses were converted to fine sporters, some of them were heat treated to engrave. I had a lovely sporter that was done in France after WWII.
It had double set triggers, incredible engraving over most of the visible sections of the receiver and half way down the barrel. It was accurate and pleasant to carry but a bear to shoot.
It had a very bad problem, exactly what the OP described. The primers would back out about .025 with factory loads and the shoulders would round out.
I really liked the rifle, so I hand loaded for it and increased the chamber pressure to around 45,000psi. Yeah I know not reccomended.
The shoulders moved ahead about .025 on the fire formed cases and I backed off the powder charge to a slower burning powder and lower pressure. Never had a problem with the rifle or the primers backing out after that.
That rifle, will never see another owner. It will be parted out and the receiver will be destroyed. I don't shoot it any more as it is light and the recoil is brutal as mentioned above.
The triggers will look good on a 7x57 build I have in mind on a Brazilian Mauser that was previously altered.
This may or may not be the case with your rifle. Take it to someone that can see inside to the locking faces in your receiver. Sometimes a dental mirror can show up the indentation but not always.
If you're only going to shoot North American factory ammunition out of it and the rifle shoots well, don't worry about it. It won't hurt anything with those loads.
If you decide to hand load, or use Norma factory ammunition, take it to a qualified gunsmith to have a close look at.
There could be other issues besides the chamber. Like the locking lugs setting back the lock up faces on the receiver. This happened once in a while to re heat treated receivers or late war receivers that weren't heat treated properly.
When many of these old war horses were converted to fine sporters, some of them were heat treated to engrave. I had a lovely sporter that was done in France after WWII.
It had double set triggers, incredible engraving over most of the visible sections of the receiver and half way down the barrel. It was accurate and pleasant to carry but a bear to shoot.
It had a very bad problem, exactly what the OP described. The primers would back out about .025 with factory loads and the shoulders would round out.
I really liked the rifle, so I hand loaded for it and increased the chamber pressure to around 45,000psi. Yeah I know not reccomended.
The shoulders moved ahead about .025 on the fire formed cases and I backed off the powder charge to a slower burning powder and lower pressure. Never had a problem with the rifle or the primers backing out after that.
That rifle, will never see another owner. It will be parted out and the receiver will be destroyed. I don't shoot it any more as it is light and the recoil is brutal as mentioned above.
The triggers will look good on a 7x57 build I have in mind on a Brazilian Mauser that was previously altered.
This may or may not be the case with your rifle. Take it to someone that can see inside to the locking faces in your receiver. Sometimes a dental mirror can show up the indentation but not always.
If you're only going to shoot North American factory ammunition out of it and the rifle shoots well, don't worry about it. It won't hurt anything with those loads.
If you decide to hand load, or use Norma factory ammunition, take it to a qualified gunsmith to have a close look at.
If you think there is a headspace problem, check with a gauge.
There could be another cause for the backed out Federal and Winchester primers.
North American made ammunition is light, loaded so it can be used in both J and S bore rifles. Firing pin drives the cartridge into the chamber, there isn't enough pressure to seat the casehead against the boltface, primer backs out.
I suspect that if you fired European sporting ammunition, you wouldn't see them.
The rifle should be checked with an 8x57 Field gauge. If it swallows that, the easiest and cheapest solution is handloading ammunition correct for the rifle.
There could be another cause for the backed out Federal and Winchester primers.
North American made ammunition is light, loaded so it can be used in both J and S bore rifles. Firing pin drives the cartridge into the chamber, there isn't enough pressure to seat the casehead against the boltface, primer backs out.
I suspect that if you fired European sporting ammunition, you wouldn't see them.
The rifle should be checked with an 8x57 Field gauge. If it swallows that, the easiest and cheapest solution is handloading ammunition correct for the rifle.
If you just want to shoot the gun, simply neck size your fired brass. If you want to eliminate the headspace, you can set the barrel back (assuming there's enough thickness in the shank or flange ), or you can rechamber. 8mm-06 is a good choice, I have a couple of the Ackley version, you will have to modify the magazine box and likely the follower. 8x68 is another option, as is the 8mm PMM (338 Win Mag necked down to 8mm),but both are more work. - dan
I believe you have a combination of headspace and cartridge head clearance. You can not measure headspace using cases, steel headspace gauges measure headspace.
If you are a hand loader you can take unfired brass and neck it up to 35 caliber... then back out your 8 x 57 sizing die so when you size a case you leave a false shoulder that holds the cartridge against the bolt face. This is done by trial and error. You want to feel the bolt closing fairly hard on this false shoulder for the first firing. When you fire a cartridge sized this way, it will fire form without the web of the case stretching and give you a stronger case for reloading than one that has been stretched due to head clearance. Then do not push this shoulder back excessively in future loadings.
If you are a hand loader you can take unfired brass and neck it up to 35 caliber... then back out your 8 x 57 sizing die so when you size a case you leave a false shoulder that holds the cartridge against the bolt face. This is done by trial and error. You want to feel the bolt closing fairly hard on this false shoulder for the first firing. When you fire a cartridge sized this way, it will fire form without the web of the case stretching and give you a stronger case for reloading than one that has been stretched due to head clearance. Then do not push this shoulder back excessively in future loadings.
Thanks for the info. No engraving on this one. As Tiriaq and Bearhunter say the pressures don't seem to be high enough to fireform the brass. Unless it is loaded hot enough to prevent the primers backing out the cases must not be stretching to form to the chamber. I'll get it checked over completely. There aren't any gunsmiths around here so I guess I'll leave it until I can make it south. The 8mm06 sounds like a pretty good option. I'm not too keen on having an 8x57 that the cartridges loaded for it won't fit in my other 8x57s. I've already got .318 and .323 bore loads to keep separate.
I agree with Tiriaq,
US made ammo is too light pressure wise and don't alloy the case to fully fireform, plus US made 8X57 usually are in the minimal dimensions range. This somtimes also happen with low pressure factory 9X57 and 9.3X57, even when they barely close on Go gauge.
No worries to have, if you're not sure try Norma or non SAAMI ammunition and your "problem" will vanish.
US made ammo is too light pressure wise and don't alloy the case to fully fireform, plus US made 8X57 usually are in the minimal dimensions range. This somtimes also happen with low pressure factory 9X57 and 9.3X57, even when they barely close on Go gauge.
No worries to have, if you're not sure try Norma or non SAAMI ammunition and your "problem" will vanish.
Most rifles will do what you describe when the ammo is loaded very mildly. So it is probably NOT a headspace issue, just a fact of life with mild ammo.
The primer develops a lot of pressure. It drives the case forward and the primer back out of the case. This happens with every cartridge. What usually then happens is the powder develops pressure and drives the case back onto the bolt face, pushing the primer back into the pocket.
The 8mm when properly loaded is a very potent cartridge, similar in power and versatility to the 30-06. With a good 196gr softpoint, there is nothing in North America it won't handle well.
Handload, or buy some Privi.
I bought a case of cheap milsurp and just make Mexican Match for the few times I need a softpoint.
The primer develops a lot of pressure. It drives the case forward and the primer back out of the case. This happens with every cartridge. What usually then happens is the powder develops pressure and drives the case back onto the bolt face, pushing the primer back into the pocket.
The 8mm when properly loaded is a very potent cartridge, similar in power and versatility to the 30-06. With a good 196gr softpoint, there is nothing in North America it won't handle well.
Handload, or buy some Privi.
I bought a case of cheap milsurp and just make Mexican Match for the few times I need a softpoint.
Thanks for all the replies. What everyone is saying makes sense. There's an amatuer gunsmith in the area that may have go-no go gauges for this cartridge. I'm going to stop by his place this afternoon to see. It did seem odd that the fired cases measured exactly 57mm including the backed out primers. I have some hotter handloads with a 318 bore bullets that I may give a try after the go-no go gauges.
Buffdog, I'm putting them in the magazine and having the bolt pick them up, although with the action work the Belgium gunsmith did the bolt will close when they are push fed.
Tex, the bolt is numbered to the action. When the action is closed, with or without a case in the chamber the lock up is very tight. I've seen a few 98 mauser that will move a fair bit with the bolt closed on an empty chamber.
I took a closer look at the stamps on the barrel. It is stamped 8X57MR (it isn't rimmed). Is that the same as mm? It has been stamped over what might be a lighter stamp of the same thing. It also has the usual B.Blindee and the Belgium proofmark for a completed import rifle. The new 8X57MR and the rest of the proofmarks looked stamped at the same time and depth. I probably wouldn't worry about this rifle too much, but when I bought it I could just barely see a hint of figure under the stain and poor finsh in the stock. I thought I would try an English oil finish and it didn't turn out too bad.
Buffdog, I'm putting them in the magazine and having the bolt pick them up, although with the action work the Belgium gunsmith did the bolt will close when they are push fed.
Tex, the bolt is numbered to the action. When the action is closed, with or without a case in the chamber the lock up is very tight. I've seen a few 98 mauser that will move a fair bit with the bolt closed on an empty chamber.
I took a closer look at the stamps on the barrel. It is stamped 8X57MR (it isn't rimmed). Is that the same as mm? It has been stamped over what might be a lighter stamp of the same thing. It also has the usual B.Blindee and the Belgium proofmark for a completed import rifle. The new 8X57MR and the rest of the proofmarks looked stamped at the same time and depth. I probably wouldn't worry about this rifle too much, but when I bought it I could just barely see a hint of figure under the stain and poor finsh in the stock. I thought I would try an English oil finish and it didn't turn out too bad.
A quick way to check for excess headspace is to partially seat a fresh primer (let it stick out a bit) in a sized case and then chamber the case. The bolt will push the primer the rest of the way in. Remove the case and examine the primer. The amount sticking out is the headspace.
No, that won't work. Headspace can only be checked with precision gauges.
Cases compress and expand. The force applied by a closing bolt can change the length (to shoulder) of a case or cartridge. Once this happens, the case no longer corresponds to the setting of the sizing die. In the way you describe, the comparison is how that case fits the chamber, the next case may be different as well as the one after that. But it is not a headspace measurement.
Cases compress and expand. The force applied by a closing bolt can change the length (to shoulder) of a case or cartridge. Once this happens, the case no longer corresponds to the setting of the sizing die. In the way you describe, the comparison is how that case fits the chamber, the next case may be different as well as the one after that. But it is not a headspace measurement.
Ganderite's method, along with firing a case with only a primer and inspecting primer protrusion, will tell you the length from the shoulder to the boltface. Not the same thing as using gauges, but will give you a pretty good idea if the rifle is loosely breeched. If the primers are hanging out in the open air, better get the rifle checked. Or just go with fireformed cases and neck sizing.
As it happens, I have a 8x57 Field gauge. Not everyone does, including shops.
A lot of rifles will accept a No Go, and are perfectly serviceable. No Gos are really useful when fitting barrels, though.
As it happens, I have a 8x57 Field gauge. Not everyone does, including shops.
A lot of rifles will accept a No Go, and are perfectly serviceable. No Gos are really useful when fitting barrels, though.
