This is the factory Heckler & Koch buffer retainer spring for the HK416 and MR556. It pushes the buffer retainer up to hold the buffer in the receiver extension. Replace a weak or lost spring with the HK part. Compare it with your existing part or the manufacturer's parts diagram to confirm it matches your firearm before ordering.
- Part: Buffer retainer spring
- Fits: HK416 / MR556
- Brand: Heckler & Koch
- UPC: 642230251632
