The DPM Mechanical Recoil Reduction System is a direct replacement for the stock recoil rod and does not change the configuration of the gun.
Mechanical Recoil Reduction System Beretta 9000 S Subcompact
This system works due to the multi spring intricate rod (3 springs) and controls the functionality of the gun. The third spring which is contained within the rod controls the movement of the slide so it never rams on the frame. Included with the system there are 2 separate springs, 1 washer so the shooter can fine-tune the weapon for his/hers personal standards.The longer spring (more coils) is stronger and has a heavier pound rating than the shorter spring.
The springs are different in length with the longer being heavier than the short when the slide is on the battery, so the shooter can fine-tune the weapon for his/hers personal standards.
The washer must always be installed when the DPM Recoil Rod and springs are used.