This build is amazing but can be BORING. Basically, get in bear, get out of bear, shoot as many Hives as you can, mop up with Kyb, Cutsman, Redistributer or Recursion. Throw grenades for health. TIP: while the gun doesn't say it, the Recursion shotgun HAS splash damage.
Shield: Transformer - anoint to taste CM: Blastmaster Art: Whatever, but I like Auto Idol's and Victory Rush's Nade: Something that Splits and Splits again with a nice "Action Skill End" anointment
Here is what it can do for quick level up or just legend farming on MH3 (MH4 is a waste of effort IMO) https://www.youtube.com/watch?v=mhNLicZ-Pmc
3 extra points go to Rushin' Offensive, Explosive Punctuation and Grizzled.