HD - I've seen even on the review for the Onza that the reviewer stated IBO speed were not attainable by him. It very well may be something about my bow that allows it to reach the IBO rating. I did notice that although it is rated at 55-70#, I cranked it all the way up and even at 28" got 73.5#. I currently have it backed down to a comfortable 65#. Plenty of juice for whtietails. I shot my last 5 buck using my Cheetah set at 53#.