Bruce, there is a lot of common sense in what you say BUT, there were many mistakes made back then. As far as Warren Page goes, he did win a lot of matches but his rifles weren't off the shelf sporters either. They were built on mostly new modern actions and to very exact tolerances. Therein, lies the crux of this discussion. To say that Keith was a proponent of higher pressures is a bit vague. Keith, liked big, heavy bullets. Townsend Whelan, thought the 30-30 Win was a real mover, when it first came out. He also felt the same way about the 30-06 later. I do agree though, in the end, they were velocity freaks. They pioneered a lot of different techniques as well. Not all of their ideas were exactly safe. There is a reason, many of their ideas, fell out of print and favor. Litigation.
Admittedly, they grew up in a different world from that of today. In many ways, it was a better world. Not so full and complicated. I to emulated those fellows and their brethren. I loved those heady days of walking into the local hardware store or gas station and viewing or purchasing the inevitable firearms racks. There was a local implement dealer, that would bring in brand new 98 Mauser's by the crate and sell them for $15 each, with matching bayonet. There was another local hardware store, Marshall Wells, that displayed handguns in the store front windows. Not even locked up at night. Those were different, though heady, wonderful days. I miss them.
Back to the original topic, safety and higher pressures. I don't worry about reaching max pressures, according to the manuals or even going slightly over them either. It's only good common sense that in a modern action, including 98s, P14s and P17s etc that there is a margin of safety built into them. A good example, is the 96 Swede Mauser, the Swedes, build just about any standard length, non belted cartridge into them. They use the same and even higher pressures than North American ammo manufacturers. In Europe, there seems to be a caveat, that the onus is on the owner to know enough about his/her firearm to do the right thing.
Now, today's modern powders are much different from what you and I grew up with. Better in many ways and more consistent. Lots of information on them as well. Not so in our earlier days and we had to experiment. In the case of the 30-06, it was literally possible to fill the case with 4831, to the point that you could barely get the heaviest bullets available, to just seat deep enough to chamber, and not expect it to come apart in your face. That just isn't a save practise anymore.
As I mentioned above, pressures generated during ignition are not incremental. It isn't just a simple thing like, increasing the powder charge by 5%, will increase the pressure curve by 5%. It could actually increase the curve by 100% or more. Is it worth it for a 10% of 5% gain in velocity?
If someone wants to play with pressure curves, study up on the powder first. Find out its parameters in as much detail as possible. Most powders are developed to perform in specific case capacities and bore diameters. Change those circumstances and the powder reacts much differently, in regards to pressure. PO Ackley, took me under his wing, one week in Utah. 1970, I walked into his workshop yard. He was just getting to work. He explained to me that his shop wasn't open. It was Saturday and in Utah, Saturdays are a special day to the Mormons. He had just dropped by to pick up a couple of rifles for a shoot on Sunday. Good guy, he asked me to come along. Now seeing as he had never seen me in his life before but remembered me as a phone customer, that was pretty big of him.
He started to explain the ramifications of pressures and the reactions of steel. He had hired a very good metallurgical engineer, to work and conduct studies in his shop. They did a lot of mathematical calculations on the expansion rate of gasses generated by burning powders, according to their quickness rates. They had developed several tables, according to manufacturer of powders, steel makers, and bullet makers. He was adamant that steel strengths varied in every batch, the same goes for powder and bullet jackets. In the end, there were far to many variables to make any of it an exact science. This is why the manuals were first produced. To keep some sanity in the practise of hand loading and safety. In those days, 2-4 inch groups, were considered not bad. One MOA rifles, weren't the norm but a treasure to cherish. About 20 years ago, the Juenke Gauge changed all of that. With this gauge, it was possible for bullet manufacturers to generate consistent jacket thicknesses all the way around the bullet, with little or no thickness variation. Beware factory seconds, inconsistent jacket thickness may be the reason. Nowadays, a one MOA rifle is pretty much the norm.
If you are cognisant as to the ramifications of increased powder charges, with the powders you are using, go ahead and experiment. When you've made any significant change in components or powder quantity, secure the rifle to a tire or some other device, stand back and with a trigger actuator (string) pull the trigger. Eject the cartridge case, if possible, and measure the case head for expansion, check for other stress indicators as well, like extreme case lenght stretch and ejector smears. Maybe, use a punch to see if you can push out the primer with finger pressure.
Play if you want. It's fun. Just use your head when safety is concerned. Don't give those hot loads out to the newbie, next door. Those loads, may just be his/her undoing with their particular rifle.
