I know this can be a controversial topic but I wanted to share what I have experienced so far.
The following information could be completely inaccurate so use at own risk, it is intended for discussion purposes only.
For quite some time now I have wanted to get to the bottom of all my questions, all those things that didn't seem to make sense. I have learned that many of my questions meet resistance on the forums but a person will never know if they don't ask.
First and foremost, Lyman's 49th handloading manual lists 44-40 high pressure loads and lists rifles that are safe and unsafe for such loads. I urge you to go get one, or if you already have one, go take a look at page 299 and page 300.
Second, Winchester and Remington manufactured high pressure loads. Winchester from 1903 to 1938. Pressures change during these years but high nonetheless. They were designed specifically for the Winchester 92 but of course later could be used in any strong action rifle, never to be used in pistols or the 73'.
To step back for just a second, when Winchester started using Smokeless loads back 1895, the cartridge box label was RED and specifically noted for use in the Winchester 73'....BUT NOT FOR PISTOLS. Meaning early Winchester smokeless loads were not to be used in those early black powder frame revolvers. However, the High Velocity loads were NOT FOR USE in the 73' or Pistols. Just wanted to make that clear.
To continue...the strain gauge. Really not much to say here because I am still learning. Since there is not much published out there. I decided after many years of pondering and reading to purchase the Pressuretrace II basic program. My doubts were that the user had to enter a known pressure for a given cartridge...and they use PSI rather than the typically published CUP. This created a problem for me but I finally over came the doubt. SAAMI lists the max pressures for both methods...PSI and CUP. We all should already now that those are 11,000psi and 13,000cup.
One of the reasons I started this whole mess is because of Winchester's modern neutered hunting loads that have only given me 1,055fps...even slower than advertised 1,190fps. This boiled my blood so for years I played with Lyman's data.
Parallel, I also played with black powder loads. Although messy and demanding they produced more powerful and even accurate results, which John Kort proved so many times, than published and factory max loads.
Finally Buffalo Bore manufactured a powerful, original ballistic cartridge that they claim remains under SAAMI max pressures. Now I had my missing link. Even though I don't know what the actual pressures are that they tested, I used their loads for my "Control". (Testing OAT was 55deg F)
When I loaded up the Pressuretrace data, entered all of the barrel dimensions, measurements, etc I still had my doubts. When I made the first few shots, my doubts dwindled down to a slight encouragement. The results were an average group of 12,900psi. But that is 1,600psi above MAX. Well, it could be and that is not really the problem since the results were based on data I entered. Since the factory load is loaded to below or at SAAMI max, I corrected the data by entering a minus correction of 1,600psi bringing the Control down to 11,300psi. No matter if this is correct or not, all other shots tested will fall into a greater or less pressure that Buffalo Bore's factory loads. This is the information I needed.
I soon discovered that all those Cowboy factory loads won't even register with my 1 1/4" thick barrel all would be less than 6,000psi. Winchester factory hunting loads came in as expected, well under SAAMI max pressures but higher than the weak cowboy loads. Two separate tests of 10 shots each resulted in both averages at 1,055fps. One pressure result avg was 6,594psi and the other was 6,762. Consistent...even if consistently incorrect!
Thus my next step was to try Lyman's both starting loads and max loads with what powders I had IMR4227, Unique and 2400,...primers and the bullets listed in the manual as well as the case and AOL lengths. I made ten tested using those published loads.
All but one Group I rifle loads were between 8,130psi and 9,389psi. One came in at 11,363psi
All Group II rifle loads came in between 12,604psi and 17,837psi. All of those Group II loads Lyman published as 19,000+ CUP....and those were not the highest. The highest is a Red Dot (427098) load of 21,900cup. One Lyman Group II load gave me 1,672fps/15,618psi avg putting it well inside the 1903-1938 High Velocity (22,000cup) category.
Including Black Powder Loads, I'll get to those shortly, I documented 43 tests @ 10 shots per group for 430 shots. Using Trailboss, Unique, Reloder 7, H4198, 2400, KiK FFFG, Skirmish FFFG and Swiss FFG.
All but one black powder loads were between 6,043 and 8,843psi. One group using Original balloon semi-head cases produced a surprised 14,100 avg psi
Several smokeless powder 1,284fps and 1,348fps loads produced less than 10,000psi while most, up to 1,586fps loads came in below 13,700psi.
My favorite and most accurate load @ 100 yards that grouped 4", clocked 1,400fps...came in below 12,000psi...well below most Lyman's published Group II loads.
I had absolutely not the first case malfunction or case damage. During all of my some 3,000 high pressure shots over the past 10 years, I only found one case with a horizontal crack close to the mouth. Not even sure it was from the HV shots, not to mention the weird non traditional crack...but found nonetheless.
Special tanks to Ed Harris and the late John Kort for their support/encouragement through these years.