I've been using Speer 100 gr. hbwc's that are sized .314 with no problems at 25 yards. I also used Magnus hard cast bullets sized .313 from Champions Choice with no problems. I have an early Pardini HP and my wife uses a Hammerli 280. From what I'm told, If you desire the best posible accuracy, then factory Lapua match ammo is the way to go. The Lapua is on the Hot side for velocity if that means anything. I allways loaded at a velocity that would'nt beat up the guns and function reliable. My Pardini SP .22 will easily shoot inside the X-ring at 50 yards on a Bullseye target. My Pardini HP might hold the 10 ring on the same target if the wind is perfectly still. If the wind is blowing a little, then a score of 96 is all I could expect while sandbagging. I used 1.6-1.7 grs of PB in mostly Remmington cases with the Speer hbwc with a Redding profile crimp. Don't expect .22 accuracy or even the accuracy of a bullseye 45, but it should group inside the 10 ring on an International target. I shot higher scores with my model 14 in the precision stage( my only slow fire 100) and use to duel better with my model 52. What brand of pistol are you having trouble with?