Product DescriptionThe Maxim Defense JP Silent Captured Spring System (heavy) is manufactured exclusively for use with the Maxim Defense CQB Stock System. Built to reduce the noise and "twang" commonly associated with traditional buffer springs, this captured spring assembly is engineered for smooth cycling in compatible AR-platform builds. For proper function, the JP Silent Captured Spring requires a bolt carrier group (BCG) with an open channel to allow the guide rod to pass during fire; a compatible modified BCG is available from JP Enterprises.Product Highlights Exclusive JP Silent Captured Spring system configuration designed to work with the Maxim Defense CQB Stock System only Heavy buffer configuration to help tune recoil impulse and cycling (application dependent) Captured spring/guide-rod design helps reduce spring noise for a smoother shooting experience Requires a bolt carrier group with an open channel for the guide rod (modified BCG available from JP Enterprises) Designed for AR-platform compatibility when used with the correct CQB stock and compatible BCGSpecs Brand Name: Maxim Defense Industries Product Type: JP Silent Captured Spring System / CQB buffer assembly (Heavy) Compatibility: Maxim Defense CQB Stock System only Platform: AR-platform (per distributor listing) Materials: Tungsten / Stainless steel (per distributor listing) UPC: 680017475710 Manufacturer Part Number: MXM-47571Disclaimer: We strive to provide accurate and up-to-date product descriptions, specifications, and images; however, errors or omissions may occasionally occur. We are not responsible for any inaccuracies or discrepancies in the content provided. If you notice anything incorrect or unclear, please contact us so we can correct it. When in doubt, we recommend verifying details directly with the product's manufacturer.