The Sig Sauer MCX Air rifle uses a 90-gram CO2 cartridge. This semi-automatic air rifle is perfect for target practice or plinking fun! It has a 30 round mag, manual safety. The durable metal housing and aluminum handguard sports a picatinny accessory rail for your favorite optics.Features include an 18 rifled steel barrel, synthetic handguard, picatinny rail, front grip, flip-up front and rear sights and more. This is the perfect Air Rifle for you.