so if you see your shotgun invisible or messed up i have a possible fix
the tf2 and hl2 use the same shotgun name
so gmod gets confused and thats why the tf2 shotgun is so messed
so if you have a fix with the shotgun gmod may think that the replacement
IS for the hl2 shotgun
and then will replace the hl2 shotgun with the tf2 fix texture
and then you will have a messed up shotgun
then you may need to uninstall any fix of tf2 fix texture addon
tho disable the mod
if you have two fixes that are compatible
disable one and test the other one
and then do the opposite
or just use shotgun retextures...
please tell if this works for you shotgun to be healty and normal once again