Manuals are a guide. What happens in your rifle will be different.
Pressure is a difficult topic to discuss.
Lets understand that your rifle was designed to meet a number of design requirements. Requiring documents are often in tens of pages, the complicated the item, the more requirements. A few very basic requirements are cost, maximum load, and duty cycle.
All mechanical structures are designed to a maximum load. This is always below material yield of the structure. For a rifle mechanism, the maximum load I would design to would be pressure maximum times the OD of the case at maximum case head separation. That will come out to pounds force. Safety factors are applied because there is uncertainty to the materials, manufacturing tolerances, heat treatments, etc. Safety factors are customary and vary by industry. They also change, typically, get smaller as technology improves processes and materials.
Commercial rifle actions are typically designed for a class of cartridges, so the M700 was designed for belted magnums, so it is actually stronger than needed, assuming similar materials and heat treatments, than what would be needed for standard (30-06) cartridges.
This is important to understand for those who want to convert old military actions to belted magnums. Military M96's and M98's were built for cartridges that had averaged 43,000 CUP.
You can build a decent sporter rifle on a Mauser but I consider that there are several factors that must be considered. The first is the age of the action. I have zero confidence of the materials from the WW1 era and before. This is the “pre vacuum tube” era. Technology did not spread as fast as an email. Technology was advancing faster after WW1 than before, especially metallurgical technology and understanding, but, that does not mean money was being spent in Military Arsenals. Military budgets had been slashed after WW1 and if the American example is similar to other Western Nations, hardly any funding went into Arsenals after WW1 for improvements. In the US, rifle production was shut down at Eddystone Arsenal, Eddystone was used as a storage depot. The Rock Island production line shut down and unfinished parts shipped to Springfield Armory. Springfield Armory had around 5129 employees in 1918, then 2,408 in June 1919, a low of 232 in 1935. After the Depression of 1929, you were lucky to have a job, 25% of the population did not. Employee numbers rebounded somewhat in 1938 to 1285 in anticipation of America entering WW2. The Defense Budget when up by a factor of five times between 1938 and 1939! Europe was already at war in 1939, but prior to Hitler, military budgets were equally as small in Western Europe.
As a rule, the older the rifle, the less certain the metallurgy. It is worth looking at the
CHRONOLOGICAL HISTORY OF CODES AND STANDARDS FOR STANDARDIZATION & TESTING DEPARTMENT https://cstools.asme.org/csconnect/FileUpload.cfm?View=yes&ID=32642 for an idea of how immature metal technology was in the pre vacuum tube era. Defining technological advancement is basically a guess, there is not a list of which industries, which factories incorporated advancing technologies. You can make a general assessment based on “everything”, an assessment which is not going to be very accurate or precise. Basically I consider the “pre vacuum tube era” to be up to the early part of the 1920’s. The closer you get to WW2 the better the manufacturing technology, assuming factories adopted improvements, such as electricity and vacuum tube based process control equipment. And that is not a given. I would say based on the technology of the era and the funding of the age, that rifles made in the 1930’s should have cleaner steels and should be made with more advanced manufacturing technology than previous decades. All of this is theoretical sophistry, someone would have to go out and test individual receivers for materials and grain structure to see if Quality Control had improved as you would expect as technology improved. Advancements in the Government sector are not linear, they are quantum. The big funding for Government Arsenals did not occur until Hitler started occupied countries in the late 1930’s.
So I consider when the receiver was made to be important for assessing risk. I also consider the cartridge to be used very important. I consider conversions of military actions to cartridges that provide bolt thrust loads above that of the standard 8mm cartridge to be risky, if not dangerous. Some cartridge conversions are dangerous in my estimation, particularly those in 60,000 + psi belted magnums.
A simple analysis:
From
Cartridges of the World
8 mm case head diameter 0.470” Area 0.1735 square inches
300 Win Mag case head diameter 0.515” Area 0.2083 square inches
Bolt face loads
8mm (Mauser design loads) 0.1735 in ² X 43, 371 lbs/ in ² = 7, 525 lbs
300 Win Mag = 0.2083 in ² X 65,000 lbs/ in ² = 13, 539 lbs
The 300 Win Mag provides an 80% increase in bolt thrust over standard military loads.
I have seen nothing to indicate that Mauser, or Yugoslavia, or FN, or anyone else building 8mm military Mauser actions built these military actions to a higher pressure standard. We know that the steels used were plain carbon steels, steels that are so low grade today they are used for cheap rebar and rail road ties. No one in their right mind today would design a safety critical rifle receiver out of such inferior materials. The average 8mm cartridge pressure did rise by a couple of thousands in WW2, that may have been because the Military was willing to accept a reduced service life, or that they thought improved production processes produced a cleaner steel. We do know from historical records lugs cracked on new service rifles.
Rifle & Carbine 98: M98 Firearms of the German Army from 1898 to 1918 Dieter writes that the bolt lugs broke on 1:1000 of GEW98 service rifles used by the Bavarian Army Corp! This was when the cartridge pressure was 43,000 psia.
There is evidence of what happens to old WW1 Mauser made receivers when chambered for inappropriate cartridges as can be seen in the lug set back in this Argentine 1909 action.
Advice for re-heat treating Zastava Mausers.
https://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/4142510/1
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Commercial rifle actions made of modern materials are sized for the largest cartridge possible, but never assume that a vintage military action won't fail with a cartridge whose load exceeds that of the standard military cartridge.
Then there is the issue of duty cycle, which I am going to say, is the maximum number of loads fired at maximum pressure. This is an interesting number that no one publishes. We know the US Army requirement for a service rifle was 6,000 rounds. And a re built M16, from a lot of rebuilt M16's, is typically fired 6,000 rounds at Anniston Army Depot as a quality check on the rebuild process. For any rifle to complete 6000 rounds without failing it obviously must be able to fire more. And what you find on AR15.com is that AR15 bolts typically fail around 10,000 rounds, some fail sooner, some fail earlier. But no rifle or mechanical mechanism is designed for an infinite number of duty cycles, except perhaps, the Pyramids. Build any locking mechanism to the weight of even the smallest Pyramid, it will last an infinity of standard pressure rounds, but the rifling will still wash out. Build a rifle not to weigh more than 8lbs, stock, lock, and barrel, and the designer has to accept, even if the user does not, that the locking mechanism will fail after a certain number of rounds are fired. You can expect that the lifetime of any light duty firearm is in the tens of thousands of rounds, like 10,000 rounds, 20,000 rounds, don't count on it lasting much more with with maximum pressure loads. Might in fact, last less.
This is worth looking at:
Fatique Life of 4140 steel
http://castboolits.gunloads.com/showthread.php?150409-Ruger-om-44-convertible&highlight=convertible
Just a few thoughts on this. For Background I am a mechanical engineer with a heavy background in failure and fatigue.
I wonder if I could request a high quality photo of the fracture zone of the cylinder? I am specifically interested in the grain structure of the bolt notches.
I put fort the following.
1) Firearms in general (the type we plebeians can get our mits one) are not designed for infinite fatigue life.
2) The Factors of safety used in firearms design are in line with low end of fatigue requirements (usually less than 10,000 cycles).
3) One of the funny things about fatigue is that each time you push the material past its original design point, you lower its expected life.
4) I am looking at this as an older gun with an unknown number of rounds through it. but based on its age a substantial round count seems likely.
5) When these firearms are designed it is generally preferable for something else to go before the cylinder lets go and takes the top strap. Generally this takes the form of the gun wearing loose or the barrel wearing out. But they are designed to handle X rounds at standard pressures.
6) I see alot of folks calculate the strengths of Rugers, but these calculations are only ever performing an evaluation on a straight static pressure basis. This is wrong when trying to determine if a load is safe.
I attached a couple of marked up figures for your perusal
If any steel structure exceeds yield, that is it stretches, deforms, it should not be used again. The cycles to failure of any steel structure is dramatically reduced if it is stressed beyond yield.
So to combine these, shoot maximum or above maximum pressure rounds which correspond to maximum or above maximum loads, the lifetime of the locking mechanism will be less than if the firearm was fired with light loads. Fatigue lifetime is directly related to load. The great the load, the less duty cycles the structure will take before failure.
If winning is the most important consideration, such as race cars, than rebuilding or scrapping an engine after ever race is perfectly fine, even though hideously expensive. Race car teams go through tens of millions of dollars a year, I heard $60 million was as little you could spend and expect to do OK. The engine just has to complete one race. These guys burn out engines and the cost is just in the noise. At the end of the season, the vehicle is probably technological obsolete and that is where barn yard finds come from.
So, are you willing to push your action so that it cracks a bolt, or deforn receiver seats, in hundreds of rounds, thousands of rounds? Are you willing to pay the cost of a new rifle and receiver at the end of each season?
There is risk with pushing things. Friends who were into race cars talked about flywheels coming through the floor boards and vehicles flipped when the drive shaft broke and speared the pavement. Any rifle or pistol action that fatigue fails, it might not give warning before exploding in front of your face. People have lost eyes when extractors blew out of actions, catastrophic failures are rather unpredictable.
By the way, I think it dangerous to rebore a used rifle barrel. The rifle chamber carries more load than the locking mechanism by virtue more surface area of the cartridge is in the chamber. Rifle barrels should be discarded once the rifling is worn. I found on another forum an example of an old 30-06 which had been shot out, then rechambered in 35 Whelen. It blew on its first or second factory round. Ounces of material were removed from the barrel, it was made of old steel, and it had gone through one service life. Why people think old pressure vessels can be weakened, then, go through another service life is beyond me.
Now the cartridge is the weakest link in the whole system. This is contrary to a dominant thought system in the American shooting society, which I call "Hatcherism". Hatcherites are rightly concerned about increasing bolt thrust, but their belief system is screwed up. It is in fact, based on an pre WW1 Army Hoax. Hatcherites believe the action is weak and the case is strong. So do Ackleyites. P.O. Ackley built his reputation and live hood on the fraudulent idea his case designs reduced bolt thrust, by making the case carry load. This is, in a word: nuts. The case is a thin brass tube/pressure vessel. The idea that the thin brass sidewalls are there to take load off a 1/2" thick steel structure, is, nuts.
The case is a gas seal, the action is there to protect the case from stretching, from rupturing. You rupture the cartridge case , gas will rush out into the mechanism, and the firearm is not designed to take the gas load, and, particularly for older mechanisms, will blow up in fragments. I have not studied the load limits of cartridges, but it is obvious brass is weaker than steel. And, if Hatcherites and Ackleyites actually tried it, they could not design any firearm following the principals of Hatcherism or Ackleyism, one reason being, they don't believe the action is there to support the cartridge case .
Anyway, regardless of the structural strength of any action, the cartridge case is far weaker.
