You can make bind for just about any weapon!
Example:
zarp_equpitem weapon_gluongun
The best way to find binds is to use "zarp_equipitem" in console then add a part of the weapon name and you should see the options.
Example: zarp_equipitem m202
then if you use the arrow keys you should see something like "zarp_equipitem m9k_m202"
then to bind those to a key simply copy the weapon equip command then use "bind key zarp_equipitem m9k_m202"
MAKE SURE TO REPLACE 'KEY' WITH ANY KEY YOU WANT TO BIND THE WEAPON TO!