When properly matched to the paint being used, a sizer will enhance air efficiency as ball enters the barrel.The HammerHead Barrel is designed for unmatched accuracy True Spiral-Rifling Provides Scientifically-Proven Rotation for Accuracy and Control Gun-drilled design that produces an ultra-consistent bore size of .688 The removable muzzle cap and X7 and A-5 compatible threaded barrel are interchangeable with after market models to create the ultimate customized look.