What would be the reason to increase the pressure? 9.3x62 does not fly far, it drops around 47 inches on 400 meters. 300 Win Mag, 338Win Mag or 6.5x55 sweede will drop 22 or so. Adding 10% of pressure won't change a thing even at 400 meters, not to mention long range. The 9.3mm chunk of lead won't fly anyway. Yet inside the 200 yards 9.3x62 has enough power to drop anything alive. Why bother?
Why do we drive vehicles with variable valve and ignition timing , fuel injection and disc brakes use transistors and fluorescent lights when those good old magneto's, points, drum brakes etc worked so well and it doesn't do anything the old stuff wouldn't do.
There has been just the odd improvement in powders, primers ( imagine , they're even non corrosive now) projectiles and brass cases since 1905, me I prefer to make use of some of those improvements. I suppose you drive a model T and shoot nothing but cast bullets propelled by black powder in your trapdoor 45/70 when your not spinning wool for your clothing.
If you take the emotion and the " tradition" out of it , a modern bolt rifle in good condition doesn't really give a #### what the chamber dimensions are cut to, what the cartridge is called or how long its been in existence. Its a pressure vessel pure and simple for that minute amount of time from ignition until the bullet exits.
Why would you not use a safe higher pressure load that delivered best performance to go with the carefully selected case , primer and projectile. Especially when you've taken the time to carefully work up to it , see no signs out of the ordinary and realize real world increases in performance resulting in extended range, more energy delivered to the target and excellent accuracy.
If we didn't bother, we'd be shooting 220 grain Krag bullets out of the 30-06 @ 2200fps , corrosive primers and all.