Power, I'm shooting an 870 supermag express turkey with a 23 inch barrel. Hevishot 3 1/2" 1 7/8 oz. #5 with an HS Undertaker choke tube. AT 40 yards I am consistently putting 60 plus pellets in a 7 1/2" circle. I'm counting 18-22 pellets in the head and neck vitals.