I've been having this problem where I've been getting automatically switched to my secondary weapon. I'm not running out of ammo. It happens mostly when I'm strafing/aiming and shooting, while sprinting in between a lot. I use a Type 95 and my primary and a Stinger as my secondary. I'm noticing it happens when I'm moving and aiming, and walking over certain terrain. This has been happening for about a month or two now.

I know it's happening when I make certain movements cause it only happens when I'm making particular maneuvers when engaging enemies. I'm otherwise very good at this game (2.75 KD) and can't blame this on just mashing the wrong buttons, cause I don't do that.  It's getting quite consistent to where I can almost replicate the problem at will.