8mm Mauser ammo on a belt... ouch!

[Slamfire]

Sorry but I think you are mistaken. The low pressure load data that is floating around is in deference to the old mausers with the .318 bore diameter.

Rifle Magazine Issue 159 May 1995 Dear Editor pg 10

http://www.riflemagazine.com/magazine/PDF/ri159partial.pdf

Ludwig Olsen :

Mauser 98 actions produced by Mauser and DWM were proofed with two loads that produced approximately 1000 atmosphere greater pressure than normal factory rounds. That procedure was in accordance with the 1891 German proof law. Proof pressure for the Mauser 98 in 7 X57 was 4,050 atmospheres (57, 591 psi). Pressure of the normal 7 X 57 factory load with 11.2 gram bullet was given in Mauser’s 1908 patent boot as 3,050 atmosphere, or 43, 371 pounds.

While many Mausers in the 1908 Brazilian category will likely endure pressures considerably in excess of the 4,050 atmospheres proof loads, there might be some setback of the receiver locking shoulder with such high pressures

Kunhausen shows similar numbers in his book : “The Mauser Bolt Actions, A Shop Manual”

Rifle & Carbine 98: M98 Firearms of the German Army from 1898 to 1918 Dieter

M98 Mauser service rifles underwent a 2 round proof at 4,000 atm gas pressure, 1 atm = 14.6 psi, 4000 atm = 58, 784 psia. Page 103. Standard operating pressures were as above, 43,000 psia. A comment on the metallurgy and process technology of the era, Dieter found records that indicated that the bolt lugs broke on 1:1000 of GEW98 service rifles used by the Bavarian Army Corp!

Gun Digest 1975 has an excellent article, “A History of Proof Marks, Gun Proof in German” by Lee Kennett.

“The problem of smokeless proof was posed in a dramatic way by the Model 1888 and it commercial derivates. In this particular case a solution was sought in the decree of 23 July 1893. This provided that such rifles be proved with a government smokeless powder known as the “4,000 atmosphere powder”, proof pressure was 4,000 metric atmospheres or 58,000 psia. The 4000 atmosphere proof was standardized for the 1893 and continued after 1911.

The article indicates it was applied to the 1898. The 1939 German proof law called for proof at 130% of service load pressure. From Mauser Bolt Rifles by Ludwig Olsen, page 134, The maximum working pressure of the German 7.9 sS cartridge was 46, 926 psi. According to sources, this round was used in machine guns after WW1 and then shortly before WW2, became a universal issue round. Use in the K98 action had to have been examined, and I expect the decision to use in the K98 would have been based on the improvement of metal quality and process technology. A proof pressure 7.9sS would be 61k psi.

I think it would be unsafe to fire a 0.323-.324 bullet down a 0.318 bore, even at SAAMI pressures of 35, 000 lbs/ in ²

 

[JeffG]

I headed that whole problem off at the pass. I bought new brass, and shoot cast loads. I don't have x-ray vision, nor am I a walking headstamp decoder. I know when I shot the old MG 15, and MG 42 of a friend of mine, he was my dad's age, I was told the ammo was hotter, and some of the contract Mausers wouldn't handle the pressure. So I play it safe...

 

[IndianaBoy]

Rifle Magazine Issue 159 May 1995 Dear Editor pg 10

http://www.riflemagazine.com/magazine/PDF/ri159partial.pdf

Ludwig Olsen :

Mauser 98 actions produced by Mauser and DWM were proofed with two loads that produced approximately 1000 atmosphere greater pressure than normal factory rounds. That procedure was in accordance with the 1891 German proof law. Proof pressure for the Mauser 98 in 7 X57 was 4,050 atmospheres (57, 591 psi). Pressure of the normal 7 X 57 factory load with 11.2 gram bullet was given in Mauser’s 1908 patent boot as 3,050 atmosphere, or 43, 371 pounds.

While many Mausers in the 1908 Brazilian category will likely endure pressures considerably in excess of the 4,050 atmospheres proof loads, there might be some setback of the receiver locking shoulder with such high pressures

Kunhausen shows similar numbers in his book : “The Mauser Bolt Actions, A Shop Manual”

Rifle & Carbine 98: M98 Firearms of the German Army from 1898 to 1918 Dieter

M98 Mauser service rifles underwent a 2 round proof at 4,000 atm gas pressure, 1 atm = 14.6 psi, 4000 atm = 58, 784 psia. Page 103. Standard operating pressures were as above, 43,000 psia. A comment on the metallurgy and process technology of the era, Dieter found records that indicated that the bolt lugs broke on 1:1000 of GEW98 service rifles used by the Bavarian Army Corp!

Gun Digest 1975 has an excellent article, “A History of Proof Marks, Gun Proof in German” by Lee Kennett.

“The problem of smokeless proof was posed in a dramatic way by the Model 1888 and it commercial derivates. In this particular case a solution was sought in the decree of 23 July 1893. This provided that such rifles be proved with a government smokeless powder known as the “4,000 atmosphere powder”, proof pressure was 4,000 metric atmospheres or 58,000 psia. The 4000 atmosphere proof was standardized for the 1893 and continued after 1911.

The article indicates it was applied to the 1898. The 1939 German proof law called for proof at 130% of service load pressure. From Mauser Bolt Rifles by Ludwig Olsen, page 134, The maximum working pressure of the German 7.9 sS cartridge was 46, 926 psi. According to sources, this round was used in machine guns after WW1 and then shortly before WW2, became a universal issue round. Use in the K98 action had to have been examined, and I expect the decision to use in the K98 would have been based on the improvement of metal quality and process technology. A proof pressure 7.9sS would be 61k psi.

I think it would be unsafe to fire a 0.323-.324 bullet down a 0.318 bore, even at SAAMI pressures of 35, 000 lbs/ in ²

I suspect some of the discrepancy we are seeing has to do with the improvements of measurement of pressure within cartridges. Copper crusher numbers aren't as accurate as the transducers we use now. +- 4k PSI wouldn't be an unheard of amount of error.

I certainly don't disagree with you that standard machine gun ammo was not initially loaded to proof load pressures. It may be as simple as a stacking of errors. 47k PSI ammo with some amount of error involved due to archaic methods of pressure measurement was actually 50k PSI ammo. 50 years of storage and the burn rate of the powder has changed a bit making it 55k PSI ammo. Stranger things have happened.

I know the brass markings I saw on my 50s era milsurp is unlike anything I have ever seen until firing Lake City M193 through a carbine gassed AR-15. That brass was extruded into the ejector hole in the bolt face and then the extrusion was sheared from the case head upon extraction/ejection. That was/is hot ammo that was known to pop primers even though the primers were crimped in place.

 

[GBExpat]

FWIW, lsudave, 250rd (disintegrating)belts of the PPU 7,92 were the subject of my last (IIRC) GREAT ammo purchase.

12-14 years ago, using SG Coupons (those wonderful coupons with which the original SG always flooded the 'net) I ordered several thousand rounds of 1982 Yugo 7,92x57 ammo in 250rd cans. With carefully selected coupons (including one of the oh-so-important-for-ammo-purchases Free Shipping coupons) the cans were delivered to my house for less than $25/can.

After 20+ years in the cans, the oil coating the ammo had thickened and it is labor-intensive to remove.

I can only try to imagine what the consistency of this oil would be after 60 years.

I haven't shot any of it in a long time ... but now I shall make a point of getting out a few of the K98ks and Wz29s for field trips around the farm.

BTW, as I recall, my 1982mfr ammo is reasonably accurate and consistent and I have zero doubt that it sports chlorate primers, so I clean accordingly.

Enjoy!

 

[GBExpat]

S.m.K. - Spitzgeschoß mit Kern

I still have ~400rds of SmK (Kern, nicht Hartkern, from a 1937 Portuguese contract) remaining in my stock. I will have to include some of that in my "field trips".

Every time I see a reference to SMK (Sierra MatchKing) it triggers a brief mental pause in me.

 

[Slamfire]

I suspect some of the discrepancy we are seeing has to do with the improvements of measurement of pressure within cartridges. Copper crusher numbers aren't as accurate as the transducers we use now. +- 4k PSI wouldn't be an unheard of amount of error.

Copper crusher was the best measuring system they had at the time, and it makes sense. You compare the amount of deformation of a copper disc under cartridge pressure, against deformation of a copper crusher under a static load. The piezo electric devices really came on in the transistor era, even though there were vacuum tube versions before WW2. But, with improvements in electronics and data collection, industry found that the copper was not reacting as fast as the pressure curve and so copper units were not actually measuring a true maximum pressure. Hence, differences in piezo units and copper units.

But, and this is the big but, legacy firearms were designed under the assumption that CUP was PSIA. That's what they thought, that's the best information they had. So if a firearm was designed to a 43,000 psia maximum load, regardless of what may be thought about CUP versus PSIA, the firearm was built to support a 43,000 psia load. I find characters all the time playing shell games with CUP and PSIA, in an attempt to confuse themselves, and us, to justify their use of loads much higher than the design loads used for legacy firearms. The consequence is that using higher pressure loads than what the original designer intended, will create a structural failure sooner than intended.

I have noticed, many, many times, that shooters think they and their firearms will last forever. Both assumptions are false. Firearms are built to a service life, so is every mechanical device in the modern age, they are built to a service life based on a number of maximum loads. Fatigue failure is an inevitable consequence for any mechanical device, it is going to happen at some point in the future. Fatigue lifetime can be increased by reducing load, but shooters don't do that, they typically are trying to shoot over pressure loads. The end result will be fatigue failure sooner than later.

Anyone remember the Italian bridge that fell down last month? Italy Bridge Collapse Leaves 37 Dead. One theory is that this older bridge was not designed for the increased traffic load of the present period. Given the age, the increase in vehicle weight, and the number of vehicles crossing, the bridge failed. Since the thing was build in 1967, it was 51 years old, and might have been beyond its service life anyway. But, deterioration due to age and the increase in loads certainly will be flagged as causes for the collapse.

 

[Rubber_Duck]

I wrote a story on THR about some '50s Yugo surplus 8mm that kaboomed on me. You can find it easily enough if you search. Shoot at your own risk.

 

[someguy2800]

I have an M48 mauser and bought a couple ziplock bags of mixed surplus Yugo and Egyptian ammo. Both result in a bolt you have to smack open with your palm. No thanks. Its berdan primed and my bullet puller wont budge them so I guess I'll be throwing them in the slough.

 

[GunnyUSMC]

I have an M48 mauser and bought a couple ziplock bags of mixed surplus Yugo and Egyptian ammo. Both result in a bolt you have to smack open with your palm. No thanks. Its berdan primed and my bullet puller wont budge them so I guess I'll be throwing them in the slough.

Send them my way.

 

[GBExpat]

Its berdan primed and my bullet puller wont budge them

Using your press, seat them a bit deeper into the case first ...

 

[someguy2800]

Send them my way.

I couldn't feel good about sending these to anyone.

Using your press, seat them a bit deeper into the case first ...

Tried that. If I had a collet puller I could probably get them.

 

[GunnyUSMC]

I couldn't feel good about sending these to anyone.

I have a collet puller. I’ve had to pull surplus ammo down before.

 

[Merle1]

I have an M48 mauser and bought a couple ziplock bags of mixed surplus Yugo and Egyptian ammo. Both result in a bolt you have to smack open with your palm. No thanks. Its berdan primed and my bullet puller wont budge them so I guess I'll be throwing them in the slough.

run them into a bullet seating die that is set to push the bullets several thousands deeper - expect to hear a "crack" when they break loose - then they will come out more or less easily.....

 

[boom boom]

A guy named Taleb wrote a book called, The Black Swan: The Impact of the Highly Improbable ...
It had a large influence in changing risk perceptions. The old saw was that Europeans thought that all swans had to be white because that is all that they observed--until the discovery of Australia which has black swans in abundance. Thus, the risk function of finding a black swan was assumed to be zero until it proven not so by nature.

The money quote useful in this discussion is "Rare and improbable events do occur much more than we dare to think. Our thinking usually is limited in scope and we make assumptions based on what we see, know, and assume. Reality, however, is much more complicated and unpredictable than we think. Also, assumptions relevant to average situations are less relevant to irregular situations, especially when the "rules of the game" themselves do change." https://infogalactic.com/info/The_Black_Swan_(Taleb_book)

Firearm kabooms are a rare event statistically but we cannot really model what the underlying risk function must be. That would require complete weapons history, metallurgical analysis (which would have to be non-destructive to predict for that particular firearm), ammunition history and condition, how many rounds had been fired, random events such as the head of the firing pin splintering and piercing the primer, firing conditions, etc. Thus, reality is pretty chaotic and rare events likelihoods are not easily predictable by rules of thumb, assumption of normal distributions, etc.

Robustness to the downsides of black swan events are proposed by Taleb as a partial cure. In the context of old firearms, firing reduced pressure rounds in old guns is one issue, thorough mechanical examination of the rifle by someone trained to detect potential problems is another, avoiding ammunition of uncertain quality and production is another, using things like approved safety glasses, gloves, and perhaps shooting jackets etc. can also reduce the effect of a kaboom, having a range first aid kit, maintaining awareness while firing to detect current problems is another, and so forth. Europeans go so far as to require proof testing when used firearms change hands in some countries.

Donald Rumsfeld got criticized for his statement below,
"Reports that say that something hasn't happened are always interesting to me, because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don't know we don't know. And if one looks throughout the history of our country and other free countries, it is the latter category that tend to be the difficult ones" https://infogalactic.com/info/There_are_known_knowns

But, he is saying the same thing as Taleb.