Choke Specifications (thousandths of an inch)

A-Beretta (Bore0.725)
B- Invector Standard Browning/Miroku (Bore 0.725)
Winchester (Bore 0.735) subtract 10 thou for accurate choking
C- Invector plus Browning/Miroku (Bore 0.740 overbore)
D-Kreighoff (Bore 0.735)
E-Perazzi(Bore 0.725)
F- Beretta Optima (0.735)