I don't really remember much from the Krauser fight, I'm guessing you mean the actual fighting Krauser bit and not the finding all the pieces bit. Just shooting out his legs with a TMP or Shotgun and then when he falters switch to a Magnum and un-load on his head usually worked alright for me, and watching the QTE's in order to dodge since a lot of them come up, he has a lot of dodge-able moves. He only gets dangerous when he's right beside you, so, keep a bit of distance and just repeat this process really, and he should go down pretty easy. Try and save Magnum and Shotgun ammo for the stand-off, use up Pistol and Rifle in the run-up to then.
I recommend the Striker personally, and the Broken Butterfly (magnum). Shoot at his legs when he approaches [using striker], then switch to BB when he's down. He'll die soon enough; but the battle doesn't stop there - you get a sweet timer until the island blows up ;p
"Bit of advice: try using knives next time. Works better for close encounters." No really, knifing Krauser actually works and is easy to pull off. But in the final part of the battle, I recommend a shotgun and a magnum. His legs are exposed and don't be afraid to unload, time is of the essence.