First, get rid of Weapons.ymt from my mod if you have one.
Second, open up the weapons.ymt file you're using and change the things below here.

Things that you need to change : 
This is what it looks like before
Same thing with this
to
This is what you need to change it with
Same thing from above
BUT, if you want it to work with john's knife do the same thing above but search up <Name>WEAPON_MELEE_KNIFE_JOHN</Name>