This is our high power valve for the Benjamin Bulldog. Our stock Bulldog produced 180fpe out of the box. We installed this valve, the provided light weight hammer spring, and ported the barrel transfer port to .30"; we then dialed a shot string up to 980fps using 127gr ammo, that's right at 280fpe at the factory recommended fill pressure. We don't know of any other modification that can get these numbers out of a Bulldog. The supplied hammer spring will also make your gun easier to cock. Please refrain from using heavy hammer springs with this valve.