Bear River Boa BB Pistol - CO2 Semi Auto BB Gun - .177 Cal 4.5mm Ammo FEEL THE POWER OF A CO2 POWERED BB GUN. Don't settle for a spring action gun when you can have power in your hands with CO2. LONG RANGE FAST - Don't be caught with a low powered gun. Be a cut above your competition. Get your ammo to your target faster with 410 FPS. FAST ACTION - Flawless semi-automatic action. This beauty will fire as fast as you can pull that trigger. Never jams and keeps you shooting longer. BE THE LAST TO RUN OUT OF AMMO - Never get caught empty handed. Huge 20 round clip that will give you the needed advantage over your competition. MOUNT YOUR CHOICE OF ACCESSORIES to the bottom picatinny rail.