So how does one mod weapons? They're misc items and thus can't be activated in inventory, and when I drop it on the ground it just gets added back into my inventory. Nothing seems to be to the effect of weapon mods in workbenches... :confused:

It's done in the inventory now. Just select the weapon and hit (by default) X. It's listed under "Repair ®" or whatever it says. That just brings up a list of mods that can be applied, click them to apply them.

well i play on PS3 and i got to my pip boy and to weapon and to the weapon i bought the mod for and hit L2 or R2 cant remember but it will say in the right had part of ur screen or it should mine does and after you do that pick the mod and its added to the weapon and its there simple as that

For PC go to Pipboy items and select the weapon. Then press X. Will bring up a list of all mods for that weapon on you. Apply from there