You would equip the type of grenade you want to use to the Grenade Launcher (say I am using the Voidwall Grenade but I wanted the use the Vortex Grenade I would just equip it on my Grenade Launcher) Feel free to suggest any weapon you like! These are just some examples and I will hopefully be updating this pole every week! I think that Bungie should add in some weapons that are not guns to make the game more interesting! I will not go into details about these weapons but if you want you can look up these weapons to learn more about them! I will also take suggestions on which weapon slot these weapons should go into! And check out the link to Benjamin Ratterman's site! He makes awesome Destiny concept art!