The stainless steel/aluminum through-hole for the guide spring is specifically designed for the Bolt Recoil Shock System (BRSS) to keep the spring in line and allow the spring to rotate on the shaft during high compression. This through-hole for the spring guide is machined with a 6.8mm through-hole on the stainless steel hub, allowing the pushrod to pass through the thrust bearing and spring guide without any restriction. The through hole for the spring guide is also fitted with an axial ball bearing, which reduces spring stress and breakage during high-speed spring compression.

Spring guide base diameter: 16mm
Spring guide body outer diameter: 10.8mm
Inner diameter of spring guide body: 7mm
Spring guide body length: 44.5mm
Total length: 51.5mm

Compatible with BOLT RECOIL SHOCK SYSTEM (BRSS). Designed for mechaboxes ver. 2 (M4, M16, MP5,...)

Weight: 13g