I'm having trouble understanding your pt. here. If your trying to say that a 60 lb.bow with a high efficiency rating like an X force can possibly outperform a less efficient bow even if it has a 70 lb. rating I don't think you'll get much argument here. Now, if your saying that there's a possibility of a 60 lb. bow being more efficient than a 70 lb. bow,well, that just won't hold water. You'd have to compare apples to apples like a 60 lb. X Force to a 70 lb. X Force. Maybe it's the title of the topic "60 vs 70...no diff. in power" that's messing me up.

Dan