And sometimes your character doesn't do anything. On more than one occasion I had to press the button multiple times for the animation to start ... and then he shoves the item back into his inventory.
(very irritating when you are getting shot at)

thanks

I can't seem to find the assignment option then .. how is it called?

Yes I did, by the time this happened I already used the Melee stuff a couple of times

"I have the oppesite problem with the M4 Silencer, with the Silencer 556 attached it won't reduce the sound noise."

In reality you need subsonic ammunition, otherwise only the explosion sound is silenced but the bullet still makes a supersonic crack and that is rather loud.

So maybe it is not implemented yet, or it is just a bug.

I would like them to be like in the ACE mod.
The 50cal sounded really terrifying (super loud).

As far as I know are the weapon sound already new. The only thing that is missing is the right volume.