56x45mm rounds. These rifles are developed on our patent pending “Multi-Caliber” selector change know-how that permits customers to easily adjust among calibers with no applications or modification simply by depressing a little lever to the remaining side with the receiver to remove a pin and rotating out the selector swap. https://noveske-rifles-for-sale52840.oblogation.com/19655595/5-simple-techniques-for-noveske-ar-15-for-sale