I have personally picked up a couple Daisy and Umarex .177 cal air pellet / bb combo rifles that are multi-pumps with bolt action loading / cocking. Velocity ranging from 600 to 800 and have hunted squirrel, possum and birds with ease. The rifles come with scopes, usually 4x15. Although they are not very fancy scopes, they are highly capable when sighted in. I am shooting 2cm groups at 25 feet and 1-1/2 inch groups at 35 feet with the included scopes. I one shot birds and squirrels at 25 to 30 feet usually, however, I have the scopes sighted in enough to get good headshots. Except a few birds that I got heart shots on because they move too much. Even at 600 velocity, my pellets penetrate plywood. I feel the usual suggestions for 1300 gamos and such are overrated for such small species. I do own a couple 1000 lead / 1200 alloy break barrel rifles, however, I don't feel the need to commonly use them as my cheaper rifles do fine. You can find these rifles roughly $40 to $50 and are very lightweight. I only use my higher end rifles when I want fast reloading, due to break barrels being a single load and single cock without the need to pump it for power even though I am aware they have more power, more power is irrelevant. Either it is capable, or not capable Overkill makes no difference to me. However, I do notice you want "the best you can get", the best you can get is simply besides the point of what is good enough.