I haven' t noticed any problems with penetration with my 4 blades. I killed 3 last year with the 4 blades and they all died within 50 yards. All pass-throughs. The blood trails were unreal. The trails looked like someone had spilled buckets of paint in the woods. Personally, I don' t think you will have any problems not matter which you pick, the 3 or the 4. I personally shoot the 4 because it shoots better out of my bow.