Although not optimum, the .17 behind the ear will work, once again, not preferred, but can work. Laws on caliber, are not really well thought out, usually decided by state or county seats. Here in Texas, any centerfire round both rifle or pistol. No restrictions on round count, unless it is a federally controlled animal, like duck, dove or geese. Limited to 3 rounds, and for water fowl, steel shot is mandatory.