The DMK22P is a dedicated .22LR, semi-automatic, pistol platform that is optimized for realistic training, accuracy, and that offers nearly limitless customization. The DMK22P fills the roll of a low cost training solution that replicates the exact form and function of the ubiquitous AR-15 pistol. The DMK22 features a patented barrel adaptor that allows for the use of aftermarket 10/22 barrels, capable of accommodating any type of performance requirement. Also, the DMK22 employs a patented bolt lock to keep the action open when the magazine is removed, allowing for the same reloading manual of arms as a centerfire AR-15. Additionally, the DMK22P is compatible with nearly all AR-15 upgrades and furniture. The DMK22 is the no-compromises rimfire AR-15.