Having the proper airsoft magazine is key when playing. Airsoft magazines come in many different configurations. Aeg magazines come in highcaps or midcaps. Hicaps will hold between 100 and 500 bbs and have to be wound after a few shots. Midcaps allow the player to load bbs and just shoot. Midcaps hold between 30 and 190bbs and are allowed at milsims. Co2 and Green gas mags are for GBB rifles and GBB pistols. Typically these magazines hold 14-50 bbs.
Making sure you have extra magazines handy that will fit your airsoft guns is crucial if you want to keep firing during your next milsim.