| Platform | Mk57 |
| Caliber | 5.7x28mm |
| Operating System | Radial Delayed Blowback |
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Parts Kit, Firing Pin Kit, Mk57, 5.7x28mm
Replacement firing pin and retaining pin for Mk57 Bolt
Kit Includes:
- Mk57 (5.7×28) Firing Pin
- Firing Pin Retaining Pin