Handgun

Magazines are consumable parts, not permanent ones, and they are the single most common cause of a semi-automatic malfunctioning. Feed lips take a set, springs weaken with round count rather than with time under compression, and followers crack. A pistol that has started stovepiping usually has a magazine problem.

Buy factory magazines for anything you rely on. The aftermarket produces some excellent ones and some that will not run, and a handgun magazine costs too little to be worth the experiment. Number them with a paint pen so a magazine that causes malfunctions can be identified and retired rather than staying in the rotation.