ASG Ultimate Upgraded M170 Spring

The Ultimate Upgrade Series doubled progressive springs make sure the torque of the motor is used to its full extent giving a higher rate of fire. Must be used with appropriate Ultimate upgraded internal components to secure the best performance and durability.

The Ultimate springs are named M100, M110 etc. according to their expected tension in meters per second – measured when using a 0.20gr BB and a 300mm long barrel.