My old 250 AI [TOY] was made on a 600 action, kevlar stock, McGowan barrel. It showed right from the get-go a real perferance for the old Nosler 100 gr Solid Base bullets. Out of the 21 1/2" barrel I get right at 3200 fps and this is with IMR 4350 and Military L.C NM cases formed into the 250/300 and then fireformed into the "AI" influence. This has pretty well become my "go to" rifle for many years because of health issues and the light weight of the rifle. No problem with these little Blacktails and an occasional elk here either.
The 250 AI has it`s +s and -s as anything else does. The plus is longer case life, added velocity but sometimes the minus side rears it`s ugly head and you lose flexibility of loading. Also there is sometimes a feeding issue with the 40 deg shoulder. Nothing insurmountable but troublesome. All in all I think the AI 250 is a wonderful cartridge. Takes a bit of work to make the cases etc but so what?
I agree with 260 Remguy 100 % on his feelings about Mr Ackleys figures except one must bear in mind! Back when PO was "doing his thing" powders were slower burning and not as plentiful. Also chronographs weren`t as accurate as they are today. I remember talking to him in the mid 70s and his saying that his old Oehler was going back to the shop for some re-calibration or something. I will NEVER think MR Ackley set out to spoof the public. He just wasn`t that sort of person, at least not from the somewhat limited contact I had with him. I love virtually ALL my 25s ranging from the 25/223 to the Weatherby. Same with the various 6.5s I have too. Would I ever part with my old "Toy"? NO!!!

Aloha, Mark