I have had great success for grouse with a .410 barrel. Use 3 inch shells and #6 shot. Keep the range fairly short and hold for the head, the shot will drop some.

If you want to use open sights a .44 mag. is hard to beat for deer. I also use a 7x30 Waters with a 4x Leupold scope mounted on it. This will about double the range of an iron sighted .44 mag. The main concern with a handgun is being able to hit your target consistently. This takes practice on a regular basis.

Lyre