Type Rimfire – Caliber .22 LR – Barrel 8 – Rail Length Monolithic M-LOK – Weight 3.25 lbs – The PSG 22 lower receiver accepts AR-15 pattern buffer tube options and the trigger and selector are also compatible with AR-15 options. The PSG 22 features a monolithic upper receiver and injection molded lower receiver. To top it off it accepts the widely available 10/22 magazine.