Why?
Sure you can load a .30-30 to sub sonic velocities with a 170 gr bullet, and Hornady sells loaded sub sonic ammo with a 175 gr. bullet. But the end result isn’t any better than a Model 92 in .44 Mag or .45 Colt loaded to sub sonic velocity and it gains very little over a 158 gr .38 special in the shorter, lighter and much smoother Model 92 action with a lot more magazine capacity.