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."
MD: I believe it was an article written by you many moons ago that convinced me to try the 257AI. IIRC you built an AI because the standard Roberts wouldn't get you up to 3000 fps with 120gr bullets. Is my memory correct?
In any case, i love my "Better Bob" and am still using it today.
