I own a Beeman import (German Mfg) .177 barrel break spring action that's on permanent loan to my brother it seems
. It's from probably 15yrs ago,,maybe a bit more.
The advertised velocity was about 700fps. The newest stuff out there will do alot better.
But, with that rifle, taking small stuff with it was/is no problem. Keep the distances within reason, use premium pellets and go for perfect shot placement.
I like the barrel cocking spring action guns as opposed to the pump-up pneumatics,,but everyone has their own particular favorites. I've owned a couple of the pump-pneumatics and lost interest in shooting them after the cardio workout needed to charge them up.
I'd go for the .177 over the .22 for the velocity an better trajectory. The .20cal would be a good compromise. Wasn't common except for the Sheriden when I was into it, maybe they are now.
My best (lucky!
) shot was a pidgeon on a X-way overpass bridge understructure from a canoe at about 50yrds. He fell a long way to the water..
I've also got a Walther LP53 pistol, cal .177, but that's strictly target in my opinion. Velocity isn't enough for small game,,perhaps starlings and such. Come to think of it,,I haven't received that loaner back either....