SHS M130 Spring

This is a M130 spring made by SHS. It should do about 440 fps but this could be way off depending on your gun. This is a dual stage spring, which means the coils get farther and close together in different parts of the spring. This is the way all aftermarket springs are while stock springs are constant rate. It changes how much force the spring applies at different points in the stroke. The high velocity of this spring makes it best for medium range DMRs or long range support weapons.

Features:
- About 440 FPS
- .058" (1.48mm) wire diameter
- Best for DMR or long range support.

UASR rating: 4.31DR
Spring rate (6kg test): 844N/m
Spring length: 175mm
More information on UASR ratings here and here.