Credit to DRUNK JEDI
2 wolfpacks should kill it if not it'll be close 3 wolfpacks and your guaranteed a kill. I fought the bastion on Blue gate go to the big circle on the map take the stairs down and then the zipline in the elevator you'll hear the bastion walking shoot it to come to your tunnel it can't get in but it can shoot with its gun into the tunnel just use the wall by the zipline you came down to shield yourself. Fireballs can come or pops so keep an eye out. Also sometimes on the wall out in the underground area is a sentinel wall turret keep a look out so it dosnt mess you up when your trying to loot your bastion kill. you can do this if you dont have wolfpacks with a ferro just bring ferro or anvil or something that's heavy ammo and lots of it and you can slowly shoot its legs till it dies or also the face of it once it's done shooting and it's reloading.