Actions such as reloading your gun or switching to your sidearm in the action menu are unnecessary and sometimes get in the way of more important ones, such as mounting a vehicle or a ladder or opening a door.
Reload already has it's very own button which I'm sure most use far more often than the action menu.
Even weapon switching between main gun and sidearm can be done with it's own key. I suggest either using ctrl+numbers ala ACE to select different weapons and the grenade launcher or simply ctrl+mouse 1 to switch between the sidearm and rifle.
Even the choice of specific type of magazine or grenade for the weapon could be put into it's own quickly accessible menu, for example via holding down the reload button.