cutting diameters are 1 1/8" for the 125's and 7/8" for the 85's. The differnce in the plywood scores comes down to penetration. The 85's made it completely through the board, where the 125's did not. both were undamaged. I think the 125's are every bit as good as the 85's, they don't penetrate as well, but cut a larger hole. The 85's are going to be geared towards hunters that don't generate much KE or for those speed freaks that want a super accurate fixed blade head. For accuracy testing I shoot 2314 aluminums 27" fletched with 4 3" feathers. For the "abuse testing" i use cabelas carbon stalkers with 3 4" vanes. The carbon arrows hold up much better. A lot of people have asked about the accuracy score for th 85. It is small and low profile, and shoots as well as any mechanical I have tried. It's flight is very similar to the wasp boss bullet, rocket ultimate stee, and rcoky traditions. Foc is the 125 grn heads is around 12% while the smaller heads would probably be right around 9 to 10%. The latter figure is just a guesss though.