Change ammunition

[Mekon]

Can anyone tell me how to select/change or even use the different types of ammo/weapons in the FMB or the QMB?I have been following these posts but all of the various buttons such as "insert,remove,add, deleteand even the custom/default in the "Loadout section",have no effect.Its as if they are "greyed out".I can't figure out what I am doing wrong,unless some of my files are corrupt or something.I have the latest Steam patch 1.11 or something.