The MCX Rattler BB Kit is a CO₂-powered air rifle that fires 4.5mm steel BBs and includes a speed loader for quicker magazine reloads. Designed to closely mirror the controls and operation of the 300 Blackout MCX Rattler, it features semi-automatic and three-round burst firing modes, an internal blowback system that produces felt recoil, and functional controls for realistic handling. The rifle uses a full-size 30-round magazine that houses a 12g CO₂ cartridge, along with an ambidextrous fire selector and magazine release. A working charging handle and bolt catch allow the bolt to lock back when empty and require a proper reload sequence to return it to battery. Additional features include M-LOK accessory mounting, a full-length Picatinny rail for optics, and fully adjustable flip-up sights, making it suitable for training drills or recreational shooting.