Whenever I try to aim down the sights, the game brings the sights up, then immediately lowers them, even if I keep the RMB pressed. Then it brings them up again and lowers them immediately and keeps doing that as long as the RMB is kept pressed.

The glitch comes and go, it seems to appear a lot more if you are crouching, but it occurs quite frequently, nearly every time I try to aim down the sights. Its extremely annoying, when in middle of a firefight, trying to pick off targets at long range, it starts to misbehave resulting in a missed shot.

I'm not using any kind of key management or mouse key binding programs and my mouse is not broken, I checked multiple times, it works fine with a number of other games with similar feature, including F:NV and F3 mods.

I heard of a workaround I haven't tried yet, involving Xmouse, but I prefer to ask about it here, maybe there is a simpler fix or workaround.

Re-map aim to a different key. If it still does it you'll know its the game at least.

Wow, I did what you said and it cleared. Also tried a new testing program for clicks, and apparently is my crappy mouse after all. When holding down RMB, it sends pulses, clearly its my mouse. Also I'm trying lowering the clicking speed in mouse settings and that seems to eliminate pulse sending and it now functions correctly.

Thanks for your help, topic closed I guess.