Description
HK MP5, SP5 Locking Piece #27 – 90 degree Machined and properly heat-treated from ordnance-grade steel. A must-have component for users running a suppressed setup or cycling a variety of ammunition. This will assist with fine-tuning pistol configurations that lack the normal resistance provided by a shouldered buttstock.
Compatibility & Fitment
- MP5
- MP5K
- MP5-N
- MP5K-N
- HK MP5K-PDW
- HK SP89
- Other custom builds or clones
What’s Included
- One HK MP5, SP5 Locking Piece #27 – 90 degree
Specifications
- SKU: HKP-21334
- MPN: RCM-GP-LP27
- Brand / Manufacturer: RCM
- Locking piece angle: 90 Degree
- Material / treatment: Ordnance-grade steel; heat treated, per production source.
Installation Notes
- Production source states this part assists with fine-tuning pistol configurations that lack the normal resistance provided by a shouldered buttstock.
- Use qualified armorer support when changing locking-piece angle, suppressed configuration, or ammunition setup.
Important Warnings
- Production source warns that locking piece selection can affect reliability, cyclic operation, and suppressed performance.
Recommended Add-ons
Related Products
Related locking-piece products are connected through shared HK locking-piece, MP5, MP5K, MP5SD, and RCM taxonomy. Selection should be based on host platform, ammunition, suppressor use, and armorer guidance rather than degree alone.




