Just the TipG 35

I managed to get this one during the 4th campaign mission, "What is this s#*%?" During this mission, you'll be stuck waiting for an elevator and a blood dragon will come rushing down the hallway at you. Before it get to you, run over to the nearby vending machine and equip the minigun, the Fazertron, the bow (duh) and some C400 if you feel so inclined. Make sure to stock up on ammo too.

Then just let the dragon chase you in circles around the crates in the middle of the room while you get its health down real low. I used the minigun to do most of the damage, although I used 500+ rounds in doing so, you might want to use some C400 to do some of the initial damage. Then to be safe, I used short bursts of the Fazertron to get the health down to a sliver. Be careful here, it's really easy to kill it prematurely. Then just keep plugging away with arrows, preferably in the glowing underbelly.

After getting the health down to a nearly invisible bar, it still took about 10 arrows to put 'er down. So if you've left much more than that, you may have to resupply arrows.