The mere fact that some very heavy loads existed prior to and following WWII should in no way convey the idea that a steady diet of them is appropriate in your vintage double. And the proof load is a proof load for testing the safety and integrity of the barrels. It is not a recommended daily diet or a guarantee that the action will withstand that level of continual pounding. Sherman Bell's tests on Damascus barrels demonstrated that even some extremely heavy charges may not blow up a gun. But there are more ways to destroy a gun than rupturing the barrels.
Despite what manufacturers and advertising hype said, fact is there are hundreds of thousands of guns that have been worn out and damaged due to heavy use and abuse, and a lot of it was from shooters who felt they needed the heaviest and highest velocity loads to be successful. An Indy car can go over 200 mph. But you won't ever see one with 200,000 miles on the engine. Some don't finish one 500 mile race.
