I just opened a pack of MX-4s this evening to try out. I was using the practice blades and I had no tuning issues whatsoever. Mine shot great and I also use the Blazers. They flew as well as my Rocky Mtn. Turbos.....the best flying fixed blade head I have ever shot. I didn't have some 4" feather fletched arrows with me at the time to shoot. They should shoot as good or better using the real blades. I will now officially carry 2 Muzzy MX-4 and 2 Rocky Mtn. Turbos in my 4 arrow quiver.