So you have this set up in the files tf/custom/mods/sound/weapons/"SOUNDNAMEHERE" but when you launch the game it won't play, it says it is missing. If you scroll up you will notice one line says unsupported 32-BIT.wav detected if you see that then all you have to do to fix it is MAKE SURE THE .WAV YOU ARE USING IS 16-BIT NOT 32-BIT, I was dealing with this for hours and no other guides were helping so I hope this one helps.