I shot a squirrel with a 5.5fpe HW30 at under 20 yards, maybe around 16, head shot, & it was very effective. This was a Revere in Sub 12 at 28 yards. Unfortunately I don’t have the time or range to do further shooting often. So, I would speculate that it could be effective at at least 50 yards, but that’s all I can offer, speculation. If/when I take it out to further distance I will report on it. Basically, I don’t think it’s a matter of power as much as accuracy.