I shoot a Ruger M77V (older model - tang safety) but mine has a 26" barrel. Centennial Model, made in 1976, and these are the two loads I use;
75 gr. Sierra HP, 50.0 gr. IMR 4895, 3,516 fps.
75 gr. Sierra HP, 57.0 gr. Win 760, 3,543 fps.
Both will shoot around an inch at 100 yards. As with any load someone gives you start under and work up, just a good idea. By the way mine is also my favorite deer rifle. Lawdog