RetroArms SR25 Spring SiCr with Progressive Winding — M140 Gearboxes included or sold separately based

included or sold separately based on batch)

Upgrade your AEG's performance with the T238 Spiral Gear Set Pro Edition — engineered for high durability and smooth operation

and precision tuning for your AEG build

rail screws

RetroArms SR25 Spring SiCr with Progressive Winding — M140 Gearboxes included or sold separately basedThe RetroArms SR25 Spring SiCr with Progressive Winding M140 is a high performance main spring designed for SR25 and extended gearbox builds that require powerful and consistent compression. Manufactured from silicon chromium (SiCr) alloy steel, this spring offers superior resilience, reduced fatigue, and long term stability compared to standard carbon steel springs. The progressive winding design ensures smoother compression, reducing stress on the