For me, even 150 is stretching it, regardless of ammo. It may be at best, the outer limits for this round. However, I have had dramatic results with the 17 gr Hornady ammo inside, say 100 or so yards. It is deady accurate, easy shooting, and explosive on groundhogs. I like to use it when I want to keep the noise level down. Great round, just no way a 250 yarder. Get a .22 centerfire for that.