Description
Laylax Prometheus Non-Linear AEG Upgrade Spring MS90
This is the Prometheus Non-Linear upgrade spring in the MS90 rating, a main spring for standard AEG gearboxes. It sits at the lighter end of the Non-Linear range, which makes it a good choice for builds that need moderate power with crisp cycling.
LayLax is a long-established Japanese maker of airsoft parts, with sub-brands including Prometheus for internal upgrades, Nine Ball for gas pistol parts and First Factory for external and replacement parts.
The Non-Linear design
Prometheus Non-Linear springs have an irregular pitch: the coils are not evenly spaced along the length of the spring. Laylax says this design eases wear on the gearbox, compresses more easily and is heat-treated for strength and consistent compression. Like any main spring, it sets the replica’s power and affects the rate of fire and the load on the motor.
Laylax grades its springs with an MS number, and a higher number means a stronger spring. The actual result always depends on the rest of the build, including the cylinder, the air seal, the barrel and the hop-up, so treat the rating as a guide and confirm the outcome on a chronograph.
Fitting
Changing the main spring means opening the gearbox on most AEGs, although some designs have a quick-change spring guide. Take photos as you strip the gearbox, keep the shims and small parts in order, and lightly grease the spring guide before reassembly. After fitting, test with no BBs loaded, then have the replica chronographed to make sure it is within your site’s limits.
Key features
- Prometheus Non-Linear main spring
- MS90 rating
- Irregular pitch design, per Laylax
- Designed to ease wear on the gearbox
- Heat-treated for strength and consistent compression
- Listed for standard AEGs
Compatibility
Laylax lists the Non-Linear spring for standard AEGs. Some gearboxes, such as Tokyo Marui’s Next Generation recoil models and certain makers’ own designs, use different springs or spring guides, so check your replica’s manual or contact us if you are unsure. A stronger spring puts more load on the motor, gears and battery, so make sure the rest of the build is suitable.
Care and maintenance
Leave the replica uncocked when it is stored, so the spring is not held compressed for long periods. Store spare springs dry, and replace a spring that has noticeably shortened or lost power. Always chronograph after any change to the internals.
Who is it for?
The MS90 suits technicians and players building a lower-powered AEG, such as for CQB or indoor sites, who want smooth cycling and less strain on the gearbox.
Please note: Spring guide and tools are not included. Always have your replica chronographed after fitting and before play.
