The BHOA Adapter is an Upgrade for the Model Alpha, Model Bravo, and Model Echo Conversion Kits.
The Evolution Bolt Hold Open Actuator Adapter allows for full function of your rifle's existing bolt catch. The CMMG actuator is compatible with any .22 Atchisson style conversion kit, dedicated or drop-in. It optimizes magazine fit and removes play between the upper and lower.
NOTE:The BHOA Actuator was designed to work with CMMG .22 LR Magazines. Extensive and complicated modification is needed for the BHOA Actuator to function with Black Dog Mags. See CMMG website for more info.