Spicy Bulgarian 7.62x54

[MarkK]

Heavy ball yellow tip Bulgarian 1955 (reinspection indicated 21 over 51 therefore, Hungarian). Stuff is hot! Cratered and occasional pierced primers. Plan to pull and dump. Recycle powder and projectile. Should I back off a a grain or two to get something comfortable to shoot?321697321698

[Uncle Grinch]

I’d pull the bullets and dump the powder, measuring each dump. Then I’d average the load weight. Reduce the average weight by at least 10% and not that on your powder storage container, along with the bullet weight. That’s what I do when I pull surplus ammo. Have done Turk 8mm and Korean 30-06. Just be sure to use a proper powder storage container and label it with the right data.

[dondiego]

What does the yellow tip refer too?

[cosmoline one]

Lead core heavy ball (182gr)IIRC

[Larry Gibson]

I've shot quite a bit of that ammunition w/o any problems. Measured psi out of my M39 Finn Sako rebuild ran 45,300 psi. Velocity ran 2566 fps. The rounds averaged 49.5 gr of square cut Nobel flake type powder.

Most often "Cratered and occasional pierced primers" in MNs are caused by improper (too much) firing pin protrusion. That is correctly adjusted when re-assembling the bolt. The combo tool for the rifle has minimum and maximum gauges for the soldier to properly adjust it when re-assembling the bolt. You might check that first.

[mehavey]

...combo tool for the rifle has minimum and maximum gauges
for the soldier to properly adjust it when re-assembling the bolt.
They made a bolt having that kind of adjustability...
...by the common (Bulgarian!) soldier?




FWIW: Bulgaria --> Thrace --> home of Spartacus

[Larry Gibson]

They made a bolt having that kind of adjustability...
...by the common (Bulgarian!) soldier?




FWIW: Bulgaria --> Thrace --> home of Spartacus

The OP didn't specifically say he was using the Bulgarian made ammunition [produced to meet Soviet specs) in a MN. That was an assumption on my part which may be incorrect. However, the information was correct as to the adjustability of the firing pin protrusion. And yes, the common soldiers were trained in the correct adjustment. That and just to be sure there was usually alignment marking stamped into the cocking piece and rear of the firing pin to assure alignment but even with that it is easy to misalign the marks if their use is not understood.

Regardless, since 99.999999% of MN owners in this country have received neither proper training in the correct assembly of the MN bolt or have read a Soviet manual many firing pins are found improperly adjusted. Too much firing pin protrusion is the major cause of cratering and piercing of the primer.

[atfsux]

Everything Mr. Gibson says is correct. I would merely add that because this is "heavy" ball meant for machineguns, the projectile is heavier than the standard "light" ball. So even if pressures are within appropriate range for safe shooting, the heavy ball is simply going to FEEL harder in recoil because more lead is being thrown forward, which equals more recoil rearward. If you are used to shooting primarily light ball, this would get your attention and perhaps convince you that this ammo is too hot or overloaded. But it isn't. The hardest kicking Mosin Nagant ammo I ever fired was Chinese 200 grain heavy ball available for a short time in the early 90s. That stuff was brutal! But it was entirely safe and the very strong Mosin actions ate it up like candy.

[Rockindaddy]

That is great ammo! That heavy Russian Ball runs my Finish Maxim like an engine. Just a constant chug-chug-chug !

[MarkK]

Thanks for all the replies. I will check the firing pin protrusion. By the by, it is actually Hungarian heavy ball 185 gr. At least that is what the receipt indicated. Happy New Year! ��

[Larry Gibson]

Headstamp indicates it was manufactured at plant 17 in '64. That would be at "Barnaul Machine Tool Plant JSC, 28 Polevaya St., Barnaul 656002, Altai Territory, Russia".

[jdgabbard]

Larry,

If you ever figure out what causes sear breakages in the MN I'd be interested in hearing it. I've got a MN that has broken three of them things over the years. They're starting to get more and more expensive...

[MarkK]

Inspection of other head stamps more clearly indicate 21 over 51. It is indeed Hungarian. Better photos added in OP.



Headstamp indicates it was manufactured at plant 17 in '64. That would be at "Barnaul Machine Tool Plant JSC, 28 Polevaya St., Barnaul 656002, Altai Territory, Russia".

[Larry Gibson]

Larry,

If you ever figure out what causes sear breakages in the MN I'd be interested in hearing it. I've got a MN that has broken three of them things over the years. They're starting to get more and more expensive...

I've never had nor seen a MN broken sear. Can you post a picture of one?

[jdgabbard]

Apologize for hijacking the thread. A comment turned into a request…



I've never had nor seen a MN broken sear. Can you post a picture of one?

Here you go, Larry. It seems to be a common enough thing that a few people on the web have posted about it. But I can’t figure out for the life of me why they break on this rifle. My other Mosins do just fine. But this one breaks them every so often…


https://uploads.tapatalk-cdn.com/20240104/742d643802680c792b344b80828e5f03.jpg


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[Larry Gibson]

Interesting, any conjectures from the other web postings?

My thoughts would be towards over zealous operation of the bolt, the bolt stop [top part of the trigger] not stopping the bolt and the sear acting as a bolt stop? The top of the trigger/bolt stop is worn? or the notch [the notch that catches on the bolt stop] at the front end of the connecting bar is worn. Either of those would cause the bolt to over ride the actual bolt stop with the sear then possibly acting as the bolt stop. That would have the effect of bending the spring part back and forth to cause the breakage.

Just conjecture on my part since I've not inspected any MN where this occurs. The manual mentions this is the probable reason(s) the bolt comes out of the action unintended.

[jdgabbard]

Interesting, any conjectures from the other web postings?

My thoughts would be towards over zealous operation of the bolt, the bolt stop [top part of the trigger] not stopping the bolt and the sear acting as a bolt stop? The top of the trigger/bolt stop is worn? or the notch [the notch that catches on the bolt stop] at the front end of the connecting bar is worn. Either of those would cause the bolt to over ride the actual bolt stop with the sear then acting ast the bolt stop.

Just conjecture on my part since I've not inspected any MN where this occurs. The manual mentions this is the probable reason(s) the bolt comes out of the action unintended.

So one thing to mention, this is a mixed parts gun that was imported. Everything with it checks out though. As to wear, nothing outside the normal. Slight bit of wear on engagement surfaces. And yes, the bolt comes out quite easily when the seat is broken.

Funny enough thing, the last time it broke was during firing. Gun when bang, nephew when to chamber another round and the whole bolt came out of the rifle.


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[Larry Gibson]

That would lead me to believe the cause is a bad/worn trigger. I'd replace the trigger and ensure the top [the bolt stop] is doing its job.

[MarkK]

I had one incident of a broken sear on an M91. Turns out the trigger needed to be replaced due to obvious wear. No further issues.

Regarding the firing pin protrusion. It’s protruding more than necessary however, I’m not able to decrease any further. May need to take the whole bolt apart. BTW, this is an M39.