Hey there, just adding to the other answer - when holster mods were introduced, they were specific to weapon types, so shotgun, SMG, etc. Bungie chose not to maker a holster mod for rocket launchers, bows, or breech-loaded grenade launchers. https://www.bungie.net/7/en/News/article/50529 Even though now the holster mods are element typed and not weapon typed, the same philosophy applies - even though it never tells you this anywhere, the holster mods still do not work with certain weapon types.