It's amazing what some can do with 6-7 foot pounds at times with a well placed shot. In my days as a young teenager, I started out with a crossman pump ( something like 650 fps with bbs, and 600 fps with .177 pellets).
Now seeing an trying some of the new PCP guns makes me scoff at myself for being so sure about the power levels of the petty crossman pump when we took shots at extreme distances at rabbits and such.
I bought the crossman 1377 pistol too -back in the days , and that was a good squirrel gun up to 25 yards max. Mmmmm mmm mmm!..