With weapon swap animation added in, if you try to switch to your weapon (from carrying on shoulder, by using hotkey, maybe inventory)
and you hold the Aim button (right mouse button), while the animation is playing
The process of bringing the weapon up looks smooth, until the gun is fully aimed in your hands, and then it does a janky, gun jumps in your hand animation.

Then, when you put away your weapon onto your shoulder (using hotkey), and hold the Aim/Raise fists button (right mouse button), while the weapon shouldering animation is playing, you will have a gun cross hair remain on your screen, even without gun out.