I have owned a couple of 250AIs and never could get close to gaining 500 +/- fps with a safe load. Maybe you could do it with a full case of Bullseye, 2400, or nitoglycerine, but not with any generally accepted powder that I could find.
On pages 333 through 335 of Volume I, POA claims the following:
250/3000 Savage
100 grain bullet with 39 grains of 4350 will go 2750
(To compare, Hornady claims that a max load of 37.9 grains of IMR 4350 will go 2800 with a 100 grain bullet on page 130 of their 3rd Edition)
250/3000 Improved (Ackley)
100 grain bullet with 43 grains of 4350 will go 3276
Do you seriously believe that you can get an additional 526 fps by burning 4 additional grains of the same powder in a larger case? I don't. I've owned and loaded for the 250-3000AI and I personally think that it runs a poor 4th in the race of short action 25s behind the 25-284, 257 Roberts, and 25 Souper.
POA knew that velocity sold rechambering work and that very few people would be able to prove or disprove his claims due to the lack of affordable chronograph equipement in those days. I have AIs, but I have begun to believe that much of what POA claimed was annalagous to the HCA story of the Emporer's New Clothes, in that they were wonderful because everyone wanted them to be wonderful.
Jeff
