Be prepared for whatever may come your way by picking yourself up a spare magazine for your compatible Thompson M1A1 from the UMAREX Legends Series. Constructed fully from metal, this high quality magazine is realistically weighted and can withstand hard impacts during rough use. A high tension internal spring smoothly feeds the .177 caliber BBs from the magazine into the firing chamber of the MP40. Two 12g Co2 cartridges power this magazine, which are housed directly inside the full metal frame. Although this magazine can hold up to 302 BBs/pellets, the manufacturer recommends not filling up the magazine the entire way to avoid jams. Stock up on everything you need for those extended training sessions, and get yourself a spare 30 round magazine today.