Problem w/ 8mm ammo

[ChronoCube]

When I was shooting a Yugo Mauser, I tried Romanian and Yugo surplus 8mm, as well as some commercial 8mm Mitchell's Mausers ammo. I could easily close the bolt handle on the surplus ammo but not on the MM ammo. On the MM ammo, it would close to about 2/3 of the way down. The rifle also passes the field gauge headspace check, with the bolt handle stopping halfway down.

Anyone know why there is a difference here? Thanks.

 

[Mr_Pale_Horse]

Assuming the MM ammo was feeding with the head against the bolt face and the claw extractor in the rim, the MM is apparently not sized properly at the shoulder or the case length (or both), seeing as your rifle still passes the field test. Contact MM and describe the problem exactly and they will likely offer an exchange.

 

[ChronoCube]

Update: I tried it with a third Yugo Mauser and the bolt finally closed. This rifle passes the field test as well, but its bolt and receiver happen to be mismatched. Maybe that's part of the reason it worked.

Would you say it's safe to shoot the Mitchell's 8mm in it? I'm not sure if the ammo is out of spec -- I was not able to find anyone online who had a similar problem. Perhaps the MM ammo is on the upper end of the headspace range for 8mm (for precision), while the two matched-bolt Mausers have slightly less headspace because they're unused and "unstretched"? I have not checked them with GO gauges so it is possible that the first two Mausers might fail the GO test.

 

[ChronoCube]

When feeding MM ammo, the bolt feels "tighter" when it closes than when I feed surplus ammo. I feel a little more friction when closing the bolt, though I wouldn't say I have to force it closed. Is that a red flag?

 

[Mr_Pale_Horse]

Is that a red flag?

No, I would rather have a tight chamber than excessive headspace.

What is more important to determine, is whether MM brass once fired is difficult to extract, shows flattened or blown primers, head separation stretch marks, or other over pressure signs.

 

[Steve Marshall]

Buy a Wilson Case Gage or find someone who has one to see if the ammunition is in spec. It sounds like the ammunition is not in tolerance which forces the question. Was this reloaded ammunition? If it is reloaded ammunition then someone surely doesn't know what they were doing. And if that's the case, what else did they screw up? Powder charge? Seating depth? etc., etc.

 

[ChronoCube]

No it is factory new, not reloaded. Maybe Mr Pale Horse can comment on your concerns?

 

[Cosmoline]

The company which shall not be named apparently also sells crud ammo. Surprise surprise! My handloads do that when I forget to resize them, and they go back in the pot for another try. I would do likewise with the ammo you got from those people.

 

[ChronoCube]

The MM ammo box says it is manufactured by PPU in Yugoslavia.

 

[NCsmitty]

Prvi-Partizan makes some very fine ammo and is reasonably priced. They also make Wolf gold at the same facility. It generally has good reloadable brass and good expanding bullets.
It seems to be loaded down like U.S. ammo though.
Sellier and Bellot is priced about the same as the MM ammo, but is a full power load. Velocity is 2592fps, energy is 2923, which brings it to 30'06 power level with 196gr bullet.

Your rifle seems to have a tight chamber, from your description.
I would check the chamber on the Mauser for dried cosmoline, and use a 20ga shotshell brush and mineral spirits to clean.


NCsmitty

 

[ChronoCube]

If commercial 8mm is loaded down for the U.S., might they also make it with slightly bigger dimensions intentionally, to avoid excessive headspace?

 

[NCsmitty]

might they also make it with slightly bigger dimensions intentionally, to avoid excessive headspace?

No, tolerances are given in the SAAMI specs for most cartridges, and factories adhere to them as a rule. Like anything, it's possible that your MM ammo is out of spec, but do check your chamber to verify that it is clean.


NCsmitty

 

[ChronoCube]

Like anything, it's possible that your MM ammo is out of spec, but do check your chamber to verify that it is clean.

I did clean the chamber earlier, and tried two types of surplus ammo, both of which went into all three rifles fine.

 

[Mr_Pale_Horse]

Contact MM and tell them your quandrous: "ball ammo feeds, the MM ammo will not". If they are worth a pittance of the salt they ask for their wares, they will send you some new, pronto.

I have two 7x57mm mausers. I prefer to neck size, and once in a while, I grab the wrong ammo, cases formed in the other chamber. My Deutsche Waffen chamber is tight(er) and it takes some effort to bring the bolt down the last 30°, as compared to my Yugo in 7x57. But, I know the load is modest, and once fired, the case slips right out.

IF you have already fired this MM ammo in another gun, and have not experienced high pressure signs, then I suspect your new gun is a tight chamber, and the ammo may be over size a bit as well. Without gauging the MM ammo as Steve Marshall suggested, it is hard to say.

If you have not fired the MM ammo period, due give MM a call and tell them you want to be a satisfied customer. We will be here to back you up . Let us know how things turn out.

 

[ChronoCube]

I did contact them a while back. The problem is I got the ammo from a private party, not from MM directly. Also, they said if they exchanged it for new ammo, the ammo would be exactly the same.

 

[PTK]

Also, they said if they exchanged it for new ammo, the ammo would be exactly the same.

So all their ammo is out of spec? Nice.

 

[Mr_Pale_Horse]

they said if they exchanged it for new ammo, the ammo would be exactly the same.

I would have them send me some as proof

 

[ChronoCube]

A followup -- I ended up shooting 60 rounds of the stuff through a Yugo Mauser. Although the bolt closed more tightly than usual when the safety was on, I didn't notice any difference when the safety was off. Anyway, I was cautious at first but the rounds ran fine. All the cases came out intact.