Considering a bowhunt for bison...my dad is to be exact.

Thinking a 2 blade fixed would be most ideal for penetrating such a big animal. He currently uses NAP razorbak which is a 2 blade with 2 bleeders cut on contact. I believe the bleeders can be removed.

What would you recommend? 2 blade? 2 blade w/bleeders? fixed? expandable?

There's a number of good 2 blades out there. My picks would probably be the Magnus Stinger or Zwickey. There's others but I can't think of them right now. I'll edit later if they come to mind. With or without bleeders, both will be fine.

Magus Stingers! They are also guarranteed for life and fly really well out of fast bows. The 150s did not do well on tests done on another forum.

I would sure think the Magnus Stinger would work well . . . but I remember an Outdoor Channel segment awhile back where Uncle Ted chased one around for the better part of a morning waiting for it to expire after putting a pretty good shot on it with a Magnus.

I think I would go with the G5 Montec on this one. About as tough as they get. More blades. Or maybe the Muzzy Phantom. Or G5 Striker. And I would most likely use an Easton Axis FMJ shaft. They help penetration as well.

Penetration is a product of many different factors. KE, arrow mass, broadhead size, shape, shot placement etc. I would first go with a slightly an arrow heavier than you normaly use for whitetail. Something at least 450 grns, 500 would be better and shoot the most poundage you can COMFORTABLY. As for broadheads I would choose somthing that is strong, with a modest cutting diameter and make sure it's sharp. A 4 blade 150 grn stinger, would be a great choice as would most any Zwickey or similar head. G5 Montects Snuffer SS's, would also work well. All of these heads offer strength, and penetration. Heads like Muzzys, slick tricks, etc will work, but your setup is more critical, and of course above all else shot placement is most important. I know I left out a lot of heads but there are way to many to name, you can check out my website www.broadheadtests.com and read through the different tests. I like NAP heads, but not the razorback. It doesn't penetrate nearly as well as similar cut on contact heads and the bleeders are NOT removeable.