Primers 1/2 popped out after shooting

tkv000

tkv000

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This is a factory Hornady 7x57 round, after shooting in my 1908 Mauser, The first box did this, and I thought it was the ammo, I shot 3 of the second box, and they did it as well, whats wrong with my rifle? My friend said it could be headspace, I'll be taking it to a gunsmith when I get a chance, but though I'd try here first, how does a gunsmith adjust headspace? (if indeed thats whats wrong)


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When you pull the trigger, the firing pin drives the whole case as far forward as it can physically go, and the primer ignites the powder. The case swells and grabs the chamber walls. The primer begins to back out and is stopped by the bolt face. The bullet begins to travel down the barrel and the case head stretches to meet the bolt face. As the case head stretches, the primer is reseated flush.

Or at least that's how it is supposed to work. In your case, the case doesn't seem to have stretched back much at all, or there is so much extra headspace it is about to seperate. Since the case doesn't seem to have the bright ring ahead of the extractor groove, my guess is this ammo may be lower pressure.
 
tkv000 said:
First 20 rounds were regular Hornady 7x57, this particular round (and the other 2 like it) were Hornady Light Magnum
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Take some masking tape... around .0065" thick...it would be nice if you could mike its thickness. Stick a piece the size of the case head on a new round and attempt to close the bolt on a factory round. Be careful its cocked and loaded.
If it cloaes add another piece and try again until it won't close. It shouldn't close on the single piece. All the others indicate a head space (too long) between the rifle chamber and that brass. It looks like you could fit 5 pieces of tape from the distance the primer has backed out.

The only way to correct the rifle is to have a gunsmith shorten the chamber.

NormB
 
that would be a headspace issue.

take a fired brass and use a punch to push the primmer out a bit more. put it in the chamber and close the bolt on it. it will push the primer in till it gets to its closed position. then you can use a pair of calipers and measure the distance it is out. .001-.009 is tolerable. anything more and its getting a bit much.

solutions are to try and fit a new bolt. find one that fits the gun better. or as another person said set the chamber back a bit.
 
Norm,

Thanks very much, all I had in the house is green painters tape, I can get 3 pieces on and still easily close the bolt, with 4, I can close it, but I have to force it.

So if the chamber has to be shortened, how is this done? I ask because it has an octagon barrel, so is the barrel actually cut down?

NormB said:
Take some masking tape... around .0065" thick...it would be nice if you could mike its thickness. Stick a piece the size of the case head on a new round and attempt to close the bolt on a factory round. Be careful its cocked and loaded.
If it cloaes add another piece and try again until it won't close. It shouldn't close on the single piece. All the others indicate a head space (too long) between the rifle chamber and that brass. It looks like you could fit 5 pieces of tape from the distance the primer has backed out.

The only way to correct the rifle is to have a gunsmith shorten the chamber.

NormB
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Aries- said:
that would be a headspace issue.

take a fired brass and use a punch to push the primmer out a bit more. put it in the chamber and close the bolt on it. it will push the primer in till it gets to its closed position. then you can use a pair of calipers and measure the distance it is out. .001-.009 is tolerable. anything more and its getting a bit much.

solutions are to try and fit a new bolt. find one that fits the gun better. or as another person said set the chamber back a bit.
Click to expand...

Thanks, I don't have any punch's small enough yet, I did the tape thing and used my calipers to measure the tape, though I'm not sure how accurate they are compared to a mic (which is on order from sinclairs) it measures out at 0.017. I don't think fitting another bolt is an option, it has a very nice custom bolt handle.
 
I had similar issues with a lever bun. Luckily it was within tolerance. If the gun isn't fitted with sights the fix could be easier as theres no need to align the sights.
 
Bits of tape tell you nothing. Take it to a smithy(call around to find one who has the headspace guages or you'll be paying for them and won't get to keep them. You could buy a set from Brownell's and check it yourself ) to have the headspace checked properly. If the headspace is bad, he'll have to remove the barrel, take off a wee bit of the chamber, rethread and rechamber. Think in terms of $70 plus per hour.
Hornady Light Magnums aren't made for a 100 year old rifle either.
 
sunray said:
Bits of tape tell you nothing. Take it to a smithy(call around to find one who has the headspace guages or you'll be paying for them and won't get to keep them. You could buy a set from Brownell's and check it yourself ) to have the headspace checked properly. If the headspace is bad, he'll have to remove the barrel, take off a wee bit of the chamber, rethread and rechamber. Think in terms of $70 plus per hour.
Hornady Light Magnums aren't made for a 100 year old rifle either.
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Pud at Bashaw is suppose to be really good, I'll head down there next weekend, the Hornady Light Mags didn't say don't use in older rifles, I went to WSS and asked for Hornady 7x57 (that was what I bought before, but regular ammo) and thats what he handed me, I didn't notice until I got home. The rifle is a full stock as well, so hopefully it doesn't need cut down to much. :(
 
Yes, Pud is a good bet.

As far as the ammo goes, the guys behind the counter at WSS are sales people, not gun smiths. When-ever you acquire an elderly rifle it is a right smart idea to get a real gunsmith to check it out BEFORE you shoot it.
 
Will do for sure. I'll check to see if he has the gauges, if he doesn't, I'll purchase them, I didn't see any on brownells, is there anywhere in Canada that carries them?

Edit:

Didn't realize there was 4 pages of them, so would I order both the "GO" and "NO GO" ?

Edit #2, The other brand has Go, No go, and field, Should a guy get the Forester, or the Clymer?
 
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If he pulls the barrel have him also check for setback in the locking lug support faces. I think the 1908 actions were considered a bit soft and prone to this. Do you notice any hesitation or drag when you first open the bolt to extract a fired case?
 
sunray said:
Bits of tape tell you nothing. Take it to a smithy(call around to find one who has the headspace guages or you'll be paying for them and won't get to keep them. You could buy a set from Brownell's and check it yourself ) to have the headspace checked properly. If the headspace is bad, he'll have to remove the barrel, take off a wee bit of the chamber, rethread and rechamber. Think in terms of $70 plus per hour.
Hornady Light Magnums aren't made for a 100 year old rifle either.
Click to expand...

Bits of tape do tell you something. It tells him taht his problem is a headspace problem which he didn't know, and it is approximately .017" too long. It tells him he needs to go to a gunsmith to get him to set the barrel and chamber back. If he buys a go and nogo gauge for the 7mm (which a good gunsmith should have or get as part of doing the job) the bolt will close on both the go, and no go guage. The bolt should not close on the no go gauge.

It is a very good method to diagnose headspace problems.

NormB
 
I called Pud at Bashaw today, he says he has the gauges, and its no problem to check it out, he's quite busy but I told him thats no problem, as I want it fixed right. I've got lots of other rifles to shoot in the meantime. I'll have him go threw the whole rifle, do a through check (As I'll have all my future older rifle purchases done now ;) ) Its a good learning experience. On a side note, whats the "Field" gauge?
 
a field gauge is for military rifles. they have a higher tolerance for headspace. if a bolt closes on a no-go they still shoot it. if it closes on a field, the gun is sent back for reworking and not shot till its fixed. a fild gauge is slightly longer than a no-go one.
 
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