I have tried a few different mechanicals over the years and all of them performed the same on an animal as your steel plate test....cut smaller than advertised. I've also had some break off. The best medicine is to learn how to tune a bow properly and use fixed heads. I shoot Slick Trick Grizz Tricks or Magnums and both of those heads group with field points out to 50 yds and beyond. They also tend to cut larger than their actual size.
