I agree with the others that there are many variables that affect this particular situation. However, I have also repeatedly heard from " the pros" that speed in the 260-270 fps range is the maximum limit for shooting fixed or replacement blade broadheads accurately. I am assuming that they arrive at this conclusion from repeated personal experience though I would offer that I, along with many others, have been able to achieve reasonably accurate groupings in excess of this " speed limit" . I believe the key to this being extensive broadhead tuning and good shooting form.

Just my thoughts.