rounds per minute. CH-47 Chinook and ACH-47A "Guns-a-GoGo" M24 A defensive armament subsystem, the M24 provides a pintle mount for an M60D 7.62×51mm machine gun at either left or right front cargo doors on the CH-47. The system feeds from standard 200-round ammunition boxes attached to the weapon. The US Army phased out the M60D in favor of the M240D and subsequently M240H. While the mount system designation remains the same, the mount itself has been extensively redesigned to accommodate the ammunition magazine and a bag for catching expended ammunition casings and ammunition links, as well as an improved roller on the pintle to prevent excessive and premature wear to the mount assembly. XM32 A defensive armament subsystem, the XM32 provides pintle mounts for either M60D 7.62×51mm machine guns or M2HB .50 caliber machine guns at both cargo door positions and at both rear emergency hatches of the CH-47 helicopter, with weapons feeding from standard ammunition boxes. This system was developed specifically for the ACH-47 helicopter. XM33 A defensive armament subsystem, the XM33 provides a mount for either an M60D 7.62×51mm or an M2HB .50-caliber machine gun on the rear cargo ramp of the CH-47 helicopter. This system was developed specifically for the ACH-47 helicopter, with the weapon feeding from standard ammunition boxes. XM34 An offensive armament subsystem developed for the ACH-47 helicopter, the XM34 provides two M24A1 20mm cannons with ammunition boxes on sponsons at the front of the aircraft fixed forward. These sponsons were also fitted with aircraft-style hardpoints that allowed the mounting of XM159B/XM159C 19-tube 2.75"-rocket launchers or M18/M18A1 7.62×51mm gun pods. XM41/M41 A defensive armament subsystem, the M41 provides a mount for an M60D 7.62×51mm machine gun on the rear cargo ramp of the CH-47 helicopter. The system feeds from standard 200-round ammunition boxes attached to the weapon. The US Army phased out the M60D in favor of the M240D and subsequently M240H, but it is unknown whether the necessity of a new cradle for the weapon (as with the M24 above) resulted in the system being redesignated. The mount is otherwise the same. CH-53 Sea Stallion/HH-53/MH-53 Super Jolly/Pave Low/CH-53E Super Stallion/MH-53E Sea Dragon Defensive armament systems for the H-53 series and developments as used by the US Navy have no known designation, but generally comprise pintle mounts at "personnel or cargo doors or windows of the aircraft." These mounts are usually equipped with either .50