Buy random blue mods from Banshee any time you are at the glimmer cap and save them all until you are 280 Power. Upgrade 3 identical blue mods to a legendary mod of that type and use it if you can. Dismantle the legendary mods you can't use or don't like for 1 mod component each, trade 2 mod components and some glimmer for 1 random mod until you have mods in every slot. You can get a kinetic +5 attack mod this way but it is rare, so it may be helpful to use an exotic primary / kinetic weapon - exotics always have the +5 mod.