Auxiliary spring Rate kit for JP Silent captured spring The Auxiliary spring Rate kit is an essential accessory for the JP Silent captured spring (JPSCS), designed to provide precision tuning for your rifle's performance. While the default spring in the JPSCS is optimized for a broad range of configurations, this kit allows you to fine-tune the spring rate to achieve peak performance, especially in rifles lacking an adjustable gas block. Customizable performance - heavier springs - if you experience the buffer head fully compressing and bottoming out during firing, consider installing a heavier spring. This adjustment can enhance the cycling efficiency and prevent excessive wear. Lighter springs - for rifles where the bolt carrier fails to lock back on the last round, even with full gas (in adjustable gas block systems), a lighter spring may be the solution to ensure reliable operation. Optimized for large-frame rifles - large-frame rifles can benefit from a lower spring rate (heavier spring) when paired with a well-tuned gas system. This combination can deliver a faster, lighter impulse, making the rifle feel as manageable as an AR-15, with smooth cycling and easy charging. Compatibility Considerations - when using the JPSCS2-10 without a JP adjustable gas system, a heavier spring is often necessary to counteract the friction and additional mass of the bolt carrier. Armalite rifles, equipped with McFarland gas rings, exhibit low internal friction between the bolt and carrier, allowing them to function effectively with a lower spring rate. Versatile and Adaptable - this spring kit is engineered to accommodate the inherent variability across different rifle platforms, ensuring that your rifle cycles efficiently with the JPSCS system. Whether you're seeking to enhance performance or address specific cycling issues, the Auxiliary spring Rate kit offers the flexibility and precision needed for optimal rifle tuning. PSCS-SPRING10-100 red spring, JPSCS-SPRING10-105 blue/red spring, JPSCS-SPRING10-110 yellow/red spring