  Recently, the Fermilab heavy-quark action was extended to include
dimension-six and -seven operators in order to reduce the discretization
errors. In this talk, we present results of the first numerical simulations
with this action (the OK action), where we study the masses of the quarkonium
and heavy-light systems. We calculate combinations of masses designed to test
improvement and compare results obtained with the OK action to their
counterparts obtained with the clover action. Our preliminary results show a
clear improvement.
