The Gunsmith is actually useful now. Not only can you use him to test out some of the new weapon foundries - the old, gravel-voiced Exo will also give you some sweet Legendary and Exotic weapons, including the Hunter's Ace of Spades hand cannon, the Titan's Fabian Strategy auto rifle, and the Warlock's Tlaloc scout rifle for just a few favors. But in order to get your hands on these weapons, you'll need to get to rank 3 with your Gunsmith faction.
The fastest way to level up your rep with the Gunsmith is to test the weapons that Banshee-44 has in stock. Each weapon requires that you do things like get a precision kills with that particular gun, or kill a certain number of one specific enemy; just read the item description for the objective. Once you fill up the weapon's experience meter, you'll earn reputation points. You can also come across DVALIN relics. These look like legendary fusion rifles by their icon. You can't use the relics, but you can turn them in for a hefty amount of reputation points at the Gunsmith.
Once you hit rank 2, talking to Banshee-44 will net you a quest requiring you to get kills with a specific weapon type (sniper rifles for hunters, shotguns for Titans, and fusion rifles for Warlocks). Complete the quest chain and you'll earn yourself a legendary (Light 280) class weapon. Reach rank 3, and you'll unlock the exotic weapon quest.
When you get the exotic quest, you're once again required to get kills using the respective class weapon, then dismantle rare and legendary weapons of that weapon type (shotguns, sidearms, primaries, etc.). Dismantling rare weapons will get you one to three weapon parts per item, and legendaries can get you up to six weapon parts, so hold on to those Year 1 legendaries until you get to this part of the Gunsmith quest. Complete these objectives then return to the Gunsmith to claim your Ace of Spades, Fabian Strategy, or Tlaloc Exotic.
Check out more Destiny tips and guides below:
How to get the Boolean Gemini exotic scout rifle in Destiny