O.L. Adcock is a mighty smart engineer. He has basically come up with a limb design that is shaped like a metal retractable measuring tape.
The slightly curved or dished design allows him to use thinner laminations that are just as rigid as thicker laminations previously used. By lightening the mass weight of the limb, he automatically got better speed and performance.
I've got a friend who has a 1 piece and I really like the way it shoots. He just got a new takedown version that is supposed to be a step above the original ACS design and even faster than before. I can't wait to try it out this weekend.