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This was not my first manual, but I decided to keep it because the data might be useful.
My first manual was a Speer Number 8 and I still have it.
Then I purchased vintage manuals, including Ackley's. Only Sharpe provided pressure tested data. The basic problem for that era was that copper crusher data was unreliable, or at least, that is what they said. Heck if I know, maybe it just took too much time and effort and the reloading manual guys made up stories to justify their behavior.
So what those guys were doing were looking at physical signs of pressure, which is absolutely unreliable. Which incidentally, is what we do, because I don't have a pressure gauge
But, even at that, copper crusher data is now understood to under estimate peak pressures. The period test method was to calibrate the load by crushing a copper disc with a static load. The deformation due to static loads were repeatable. But, chamber pressure is dynamic and the copper disc did not deform fast enough to record peak pressures. And then, it was assumed that pressure was uniform in the case as pressure built.
At a regional I talked to a cartridge case production engineer. He said with today's technology, they are measuring peak pressures in the neck area that are higher than the base or mid section. That was a surprise. I would never have thought that was going on.
Vintage firearms should have been designed to a load based on peak cartridge pressures. If you know the firearm was designed to 50 K psia, and the actual cartridge pressure of an old manual load is now known to be 65 K psia, instead of the 50 K psia of the copper crusher, well you have to cut the loads. Sorry.
Now the risk of not cutting your load is a reduced service life of your firearm. Given the weight of the thing, the designer had to make assumptions of the service life of the locking mechanism, barrel chamber, or the cylinder. You the customer want an infinite lifetime, but you don't want to carry a 20 lb .22lr single shot pistol. Fatigue lifetimes are 100% correlated to material thickness and weight. The typical rifle design lifetime is in the tens of thousands of rounds, not hundreds of thousands. You can expect, if you use maximum loads, for your bolt lugs to crack somewhere between 10 and 20 thousand rounds. Better steels might take it out to 30 thousand.
For revolvers, I know one shooter who has shot 600,000 rounds of 148 LWC and 2.7 grains Bullseye in a K frame S&W. He is a 10 time PPC National Champion and a 2X National Bullseye Champion. A firing pin broke, the extractor star wore out, timing when to hell, but that was about all he could recall. You look at the pressures of his load, and it is very light. He did have to make major, with another K frame pistol, and he cracked barrel ends. Given enough pressure cycles, the steels in your firearms will fatigue fracture. There is not enough weight in the firearm for an infinite fatigue life for the higher pressure cartridges. Sorry. You push pressures, you reduce the lifetime of your firearm. You decrease pressures, you push out failures to fatigue fracturing.
I will say, what you read in the popular press is written by shills who have absolutely no technical understanding of firearm design and don't need it for their job. They are given their talking points, as determined by marketing, their customer base is assumed to be slightly more educated than a troglodyte,(but still drags their knuckles) and absolutely uninterested in materials and design. Modern day troglodytes just want something cheap that goes bang, the hell with how it works. So what happens over time, is the inbred shills in the press more or less agree on a set of ideas that have been found very successful in increasing sales, but these dogmas are closer to Cargo Cult Science It was particularly bad post WW2, with Ackley, and of course the kinetic energy theory of stopping power.
My first manual was a Speer Number 8 and I still have it.
Then I purchased vintage manuals, including Ackley's. Only Sharpe provided pressure tested data. The basic problem for that era was that copper crusher data was unreliable, or at least, that is what they said. Heck if I know, maybe it just took too much time and effort and the reloading manual guys made up stories to justify their behavior.
So what those guys were doing were looking at physical signs of pressure, which is absolutely unreliable. Which incidentally, is what we do, because I don't have a pressure gauge
But, even at that, copper crusher data is now understood to under estimate peak pressures. The period test method was to calibrate the load by crushing a copper disc with a static load. The deformation due to static loads were repeatable. But, chamber pressure is dynamic and the copper disc did not deform fast enough to record peak pressures. And then, it was assumed that pressure was uniform in the case as pressure built.
At a regional I talked to a cartridge case production engineer. He said with today's technology, they are measuring peak pressures in the neck area that are higher than the base or mid section. That was a surprise. I would never have thought that was going on.
Vintage firearms should have been designed to a load based on peak cartridge pressures. If you know the firearm was designed to 50 K psia, and the actual cartridge pressure of an old manual load is now known to be 65 K psia, instead of the 50 K psia of the copper crusher, well you have to cut the loads. Sorry.
Now the risk of not cutting your load is a reduced service life of your firearm. Given the weight of the thing, the designer had to make assumptions of the service life of the locking mechanism, barrel chamber, or the cylinder. You the customer want an infinite lifetime, but you don't want to carry a 20 lb .22lr single shot pistol. Fatigue lifetimes are 100% correlated to material thickness and weight. The typical rifle design lifetime is in the tens of thousands of rounds, not hundreds of thousands. You can expect, if you use maximum loads, for your bolt lugs to crack somewhere between 10 and 20 thousand rounds. Better steels might take it out to 30 thousand.
For revolvers, I know one shooter who has shot 600,000 rounds of 148 LWC and 2.7 grains Bullseye in a K frame S&W. He is a 10 time PPC National Champion and a 2X National Bullseye Champion. A firing pin broke, the extractor star wore out, timing when to hell, but that was about all he could recall. You look at the pressures of his load, and it is very light. He did have to make major, with another K frame pistol, and he cracked barrel ends. Given enough pressure cycles, the steels in your firearms will fatigue fracture. There is not enough weight in the firearm for an infinite fatigue life for the higher pressure cartridges. Sorry. You push pressures, you reduce the lifetime of your firearm. You decrease pressures, you push out failures to fatigue fracturing.
I will say, what you read in the popular press is written by shills who have absolutely no technical understanding of firearm design and don't need it for their job. They are given their talking points, as determined by marketing, their customer base is assumed to be slightly more educated than a troglodyte,(but still drags their knuckles) and absolutely uninterested in materials and design. Modern day troglodytes just want something cheap that goes bang, the hell with how it works. So what happens over time, is the inbred shills in the press more or less agree on a set of ideas that have been found very successful in increasing sales, but these dogmas are closer to Cargo Cult Science It was particularly bad post WW2, with Ackley, and of course the kinetic energy theory of stopping power.
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