Well, I conducted a little "test" last night. I had mounted a single bevel trade point, and had it lying nearby. I took a piece of paracord and pushed the point past. Nothing. I sharpened it. Now it cut slightly. I took one of my brother's Zwickey broadhead arrows and did the same. It cut beautifully. The difference in sharpenning was also noticeable. The single bevel points are in a short, narrow design that puts the shaft very close to the point- making it difficult to remove the bur from the flat side. So, I'm opting for double bevel- extra penetration is of no use if you can't get it sharp!