As Grauhanen has said about recoil, the rifle needs to recoil. Being clamped down so it does not recoil is not allowed in competition, unless you just want to for yourself. I am pretty sure you will find grouping will be worse clamped solid.
Yes I understand that the recoil must be a free motion, sorry if I miss spelled that earlier anywhere.
What rests did you try out of curiosity?
based on my reading his posts on this and another site ...might be best just to let him build stuff on his own
bigHun, it's very possible that a rest isn't the best choice for the model of rifle you intend to use with it. That would be my opinion.