My everything gun is a .45, and my loads go from 23 grains FFFG (about 950 fps) to 80 grains FFFG ( about 2200 fps).
I've taken small game with both loads, however, at the upper end, you do not want to miss the head of a squirrel. There is nothing left, just pieces hanging from some branches and leaves stained red.
With the small 23 grains load , I do not need to be concerned at all. I've taken squirrels shot thru the center mass and lost no meat.
Never felt the need for a smaller gun, but hen again , that could change . There is not such thing as enough guns.