COLT 1911 MK 80 IV OFFICER Bull Barrel .45 ACP 40S&W 9x19 9x19 0mm are for use with

0mm are for use with heavy ammunition and the 2 long springs with wire diameter 0

the DPM Recoil System offers almost double force in the slide full open position compared with the factory OEM spring

Thunder Pro & XT

compared with the factory OEM spring and functions as a buffer on the slide

The microscopic plating

COLT 1911 MK 80 IV OFFICER Bull Barrel .45 ACP 40S&W 9x19 9x19 0mm are for use withDPM Mechanical Recoil Reduction System for COLT 1911 MK IV 80 Officer . 45acp This system works due to the multi spring intricate rod (3 springs) and controls the functionality of the pistol. The third spring which is contained within the rod controls the movement of the slide so it never rams on the frame. The system includes 1 spring plug and 3 different external springs. The spring plug must always be installed when the DPM Recoil Rod and springs