It is NOT COMPATIBLE with .177 cal MCX/MPX airrifles. The MCX VIRTUS PCP rifle is the latest expansion to the SIG AIR precision line of airguns, and the introduction of SIG AIR products to the pre-charged pneumatic (PCP) category of airguns. The MCX VIRTUS PCP doubles the muzzle energy of classic CO2 models and uses the SIG Rapid Pellet Magazine making it a great tool for target training and defending against unwanted varmints. This Magazine and Pellets bundle is compatible ONLY with MCX VIRTUS PCP .22 cal air rifle.