GMT M110 Spring

This is a M110 spring made by GMT. It should do about 390 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 higher velocity of this spring makes it best for long range setups that are still full auto and not DMRs.

Features:
- About 390 FPS
- .055" (1.4mm) wire diameter
- Best for long range setups

UASR rating: 3.38DR
Spring rate (6kg test): 634N/m
Spring length: 179mm
More information on UASR ratings here and here.