FN 509® Training Pistol Specs Caliber: 9mm FX Operation: Double-action Mag Capacity: 17 Rd. Weight: 26.9 oz. Barrel Length: 4.1" Overall Length: 7.5" Twist Rate: 1:10" RH Length: 7.4" Height: 5.56" Width: 1.35" Trigger Pull: 5.5 - 7.5 lb. Sight Radius: 5.79" Primary Features ...