The Heckler & Koch Spring, Buffer Retainer, HK416/MR is a factory-engineered buffer retainer spring built specifically for HK416 and MR556 platforms. As an original HK component, it is designed to maintain proper tension on the buffer retainer, helping the rifle’s receiver extension and buffer system operate smoothly and consistently over extended use.

This small but critical rifle part is ideal as a replacement for worn springs or as a spare for shooters who rely on their HK416 or MR556A1 rifles. By supporting consistent buffer retention and return, it contributes to reliable cycling and helps keep your rifle running predictably during range sessions or training days. Backed by Heckler & Koch’s reputation for precise engineering, this spring integrates cleanly with compatible HK systems.

Key Features:

• Manufacturer: Heckler & Koch
• Model: 50233121
• Type: Buffer Retainer Spring
• Platform: HK416 / MR556 / MR556A1