Prometheus Upgrade Spring MS90

The MS90 rating indicates the spring is designed to achieve a muzzle velocity of approximately 90 meters per second, or roughly 295 feet per second, when installed in a standard AEG setup. Keep in mind that your final velocity will vary based on your specific air seal, barrel length, and hop-up settings.

A non-linear spring features coils of varying density, which helps reduce stress on your gearbox during the initial compression phase. This design typically results in a smoother firing cycle and less wear on your internal components over time.

This spring is designed for standard TM-spec gearboxes, which are the industry standard for most electric airsoft rifles. If your rifle uses a proprietary gearbox design, you should verify compatibility with your manufacturer's specifications before installation.

Yes, the violet coating is a functional color-coding system used by Prometheus to help you quickly identify the spring's power rating. It makes it much easier to organize your parts bin and grab the correct spring without needing to test or measure it first.

Because the MS90 is a relatively mild upgrade, it generally does not require a full internal overhaul. However, it is always good practice to ensure your piston, gears, and motor are in good condition to handle the consistent compression this spring provides.