Is this the same as the interrupted-reload bug? This affects (that I've tested) PPSH, SVT, MP40 and DP28 at least. Start reloading, then change your movement status or iron-sight status (e.g. if you were moving, stop; if you were stationary, move) during the anim. Pretty much at any time up until the anim reaches the 'ACTION' stage (e.g. cocking the weapon), if you interrupt the reload you'll get an unfireable weapon. You have to reload (again) to fix the problem. Damn annoying... easily fixed by the game remembering that you've fitted a fresh mag, and going to ACTION by simply cocking the weapon as soon as you can.