Not sure what to make of them??? They fly great. No doubt they are durable. But..... I shot a white tail doe this fall and practically nailed her to a tree with an FMJ tipped with a 100gr Montec. Sharp quartering shot through 18" of deer. After a short run she dropped in her tracks and didn't even twitch. Thing was that the blood trail was scant! Three days later I took a longer (but within reason) shot at a muley and got a complete pass through. No blood other than what was on the arrow. I backed out and recovered the deer after more than a day of looking. The shot was a little farther back than what I wanted but I did catch the off-side lung. I tried to touch up the blades every time I went out, but they are just not sharp like a replaceable, fixed blade head. I wonder if the cutting diameter is sufficient as well? I bugs me because I was very impressed with how well these heads tuned, flew, and grouped. Trying the CS heads right now and bought an Arkansas stone which seems to put a better edge on them.