There will be 5 tiers, standard, superior, exceptional, rare and legendary
To help craft stronger weapons, you'll need to increase your intelligence, high intelligence will mean you gain access to higher levels of rarity with the maximum rarity, legendary offering a 20% increase on stats from the base level.
If you wish to grind out those stats and kit yourself out, you can respecc yourself at Herne for 200 hoots as well!