My Ruger #1 heavy rifle is a 505 Gibbs. With a Pacnor straight taper barrel and one breako mercury do-dad in the butt it weighs 12+lbs with a Weaver K2.5 Microtrack mounted on the Ruger quarter rib. My rifle balances just forward of the receiver. You should be able to hit your 10lb wieght by carefully choosing the barrel contour and length.

Otto