We've tried them in a TC Prohunter, CVA Accura's and Optimas, a Winchester Apex, and a Knight Bighorn. Never had one shoot less than 6" at 100 yards. The Knight was about 8", and the TC wouldn't even touch paper. Groups larger than the target. They also drop like rocks. The "belts" don't seal and engage with the rifling, so you get lots of expanding gasses blowing past the projectile instead of pushing it out the barrel. We average probably about 300 FPS slower with powerbelts than the .45 Cal 250 Grain Hornady SST's over 100 grains of Triple 7 with the same charge weights, and the SST's give us sub 2" groups. Heck the Winchester Apex shoots 3 into an inch at 100 yards!I'm surprised to hear this. The Powerbelts are shooting impressive 3" groups at 100 yards for me.
Stainless barrel, 1 in 28" twist rate.
We've also been very disappointed with the "expansion" of the powerbelts on game. We had a friend that shot them a couple of years, and the bullets never really expanded, they just kindof shredded and tore down the side, almost like there was a perforation down the side of the bullet from the plastic tip down towards the base. He never lost a buck, but they came apart way more violently than we felt they should have, and way too unpredictably. The SST isn't exactly a premium bonded bullet, but they always expand like they should and we end up finding them in the off side under the hide 95% of the time, looking like a textbook expansion.
Too many bad experiences with Powerbelts... they're not allowed in my camp haha.