Filaman,
I got considerably more velocity out of the .257 AI when I was using one 20 years ago, but I was more of hot-rodder then.
But have also gotten 2950-3000 fps out of 115-120 grain bullets in the standard .257 with modern powders by adding only a grain or so to +P data.
However, eventually sold my .257 AI because even with 115s at 3100 and 100s at 3300, I never could tell any difference in trajectory or "killing power."
