Description
HK UMP 9mm -Semi-Auto Bolt Group
The semi-auto bolt group is required for HK USC to HK UMP caliber conversions. The full-auto bolt carrier will not work in HK USC rifles.
Includes:
- Extractor
- Firing pin Retaining Pin
- Firing pin & Spring
Specifications:
- Tungsten filled
- Heat treated
- Parkerized
