The rifle was built on a Laurona 20 gauge. The load is 43.1 grains of IMR 4350 behind a Hornady 174 grain round nose. I can't say that I was 100% happy with the performance of these bullets. They are very accurate in this rifle but the core and jacket separated completely on the shoulder of that Nyala bull. I'm going to order a few boxes of 180 grain RN from Hawk and see how they shoot in this rifle.