The 9mm Rimless Revolver PitBull now features a 5-shot cylinder in line with the rest of the PitBull family. The 9mm uses same unique rimless cartridge extractor assembly system as the Charter Arms .40 caliber Rimless Revolver. A dual coil spring assembly located in the extractor allows insertion and retention of a 9mm cartridge in each chamber of the revolver's cylinder. After firing, the shooter can easily eject the spent cartridges for immediate reloading. Blacknitride+ is a new, proprietary process that adds hardness to the finish of the revolver. It also reduces friction and wear. With a scratch-resistant surface and extended life in the rifling and chambers, Blacknitride+ keeps your Charter handgun looking - and working - like new.