Well, if you change from the Delats to Magnus I, you will have to shoot each one to make sure it is mounted staright. The magnus is a little wider and they have to be on right or will plane on you. I have and do shoot the magnus for practice and put the bleeders in just for hunting. No difference in flight for me. That said I have just switched to the 2 blade version of any of these. I mix 'em up. I shoot Deltas, Magnus, Ace, No Mercy. Mounted properly They all shoot great for me.