well shoot, i was hopin it would kill em at close range, this ruger inpact breakover shoots 800fps and it will knock a squirrels butt off at 25 to 30 yards and farther if i can hit em. lol but it wouldn't be worth a crap diller hunting. all of it takes place at night and no place for a light. my OCD won't let me just tape one to the stock or barrel, plus the thing weighs a ton. these things are blind and when DD corners one i can get really close. i'm shootin em with a gamo 177 with no sights now. that's how close i can get.From what I saw on the sig site it was only pushing 600fps, that ain't real fast for a .22. I'd look for something closer to 1000fps. Yes, you can remove that tank without losing all your air, though you don't need to remove it to fill it. Probably 10+ fills off a scuba, but your scuba tank might only be 2200psi so you obviously won't get more pressure than that out of it.