I was given a few of those last year, and they shot great in my .275 Rigby 1903 Springfield. The Manson .275 reamer I used let me snug those up just right in the chamber. Case was filled to the middle of the neck with WW2 surplus 4831, 2550 f/s from the 26 inch barrel. You will love the bullet. That was the fastest I ever shot a cast bullet, BTW.