A Warning that one might want to check their state game laws before venturing out for small game with a gun and "ammunition" meant for large game. A warden won't know or care if you're only putting 20 or 30 grs down the barrel.
In Minnesota "No person may possess a firearm or ammunition outdoors during the period beginning the fifth day before the open firearms season and ending the second day after the close of the season within an area where deer may legally be taken by firearms." They then list exceptions which includes a .22 rimfire, shot #4 or smaller, handgun with a carry permit, etc.
Of course one is OK if they actually have a big game license for that season. But net is, in Minnesota, if you were hunting squirrels with a deer-sized bore and ammunition during an open firearms deer season you could be ticketed.
This makes sense because poachers will say "Oh, I was hunting squirrels with my .300 Winchester Mag!"