started load testing for my new/used 338 ultra mag yesterday. didn't get anything better then about a 2.5" -3 "group. new cases, 250gr AB, retumbo , and H1000, started 2.0 grains less then max and increased in .5 grain increments. bullets were seated as long as the magazine box would allow. i didn't have any reloader 25 to try. the primers had some cratering, but were not flattened, and bolt lift never got hard on any round. did have one primer blow thru and ruin the case on the lowest H1000 load. gun is rem 700, muzzlebrake, 3.5 lb trigger, leupold 4.5 x 14 vxIII. i think i'll try some 225 AB and some reloader 25 with the 250's. i didn't resize the new cases, just primed and loaded them up. problem?