I started out with right wing fletch to right wing Grizzlies when they first came out, because I had a right wing fletcher. We shot a few deer with them, lost none of the deer that we hit and sharpened them like Hill would sharpen them or sharpened them according to package directions. I got tired of that nick on my finger from the right wing feathers, so I got a left wing flecher. The cut on my index finger healed up, finally, I noticed no difference in flight or the penetration on the deer we shot. I did notice that the incoming broahead hole at times, twice, did not have the little turned edge that the exit wound had. When I went to left wing single bevel Hills, I noticed a better blood trail, about the same as I got from Zwickey Deltas. Some of which I sharpened to a hair shaving edge and other times a serrated edge, but I could not tell any difference in the blood trails or the penetration from one sharpening method to the other. Before anyone jumps on me for the serrated edge, there is a difference between being merely rough and keen with a serrated edge. If in doubt, stick with shaving sharp with these or any type of head. But as far as the penetraiton and the fighting wing, my wife shot a nice fat doe that jumped her string with left wing arrow and a right wing file sharpened Grizzly. The arrow skidded on the rear right hip bone enough to leave a cut in it. The arrow stopped burried to wood in the far left scapula. The head cut everything that there was to cut and even with no exit wound the blood trail was short and heavy. I think getting the arrow to fly straight behind the broadhead will get results with any good head.