Luth-AR 308-BS-10B Buffer Spring .308/7.62mm AR-10 Rifle Length

The Luth-AR 308-BS-10B is a rifle-length buffer spring purpose-built for AR-10 platform rifles chambered in .308 Winchester / 7.62x51mm NATO. Designed as a direct replacement or upgrade spring for the A2 rifle-length receiver extension, it provides the correct tension and weight balance to keep the bolt carrier cycling smoothly and reliably in larger-bore AR-pattern rifles.

Manufactured from tempered spring steel, this buffer spring features 38 coils wound over an overall length of approximately 13 inches. The tempered construction delivers the consistent spring rate needed to manage the heavier bolt and buffer mass of .308/7.62mm AR-10 rifles, supporting both factory and custom builds. Whether you are assembling an AR-10 from the ground up, replacing a worn-out spring, or simply keeping a spare on the bench, the 308-BS-10B is a straightforward drop-in part for the traditional rifle-length buffer tube configuration.

Luth-AR has long been a go-to source for practical, mil-spec-inspired components across the AR platform, and the 308-BS-10B drops right into the A2-style rifle-length buffer tube found on most classic AR-10 rifles. New from Luth-AR, this is an inexpensive but critical consumable that any AR-10 builder or shooter should keep on hand.