12 gauge is the most popular for turkey hunting due to dense patterns and long range. 20 gauge has become very competitive with modern TSS ammunition and offers less recoil.
What choke should I use for turkey hunting?
An extra-full or turkey-specific choke is essential. It tightens the shot pattern for head shots at 30-50 yards. Many hunters use aftermarket chokes from Carlson's, Kicks, or Indian Creek.