Pglasgow,
While I see your point on sabots, etc. I think the advantage it gives is in flater trajectories more so than effective range. In the hands of a practiced shooter who knows his rifle there is little or no advantage in range. A medium to heavy lead conical is as effective at long ranges and in many cases has more energy at longer ranges than many popular sabot rounds. Trajectory can be compensated for as long as the range is known.

Having the flater trajectory does help, especially for those who don'tpractice often enough to know what their gun and load are capable of. A muzzleloader is still not going to compete with even a 30-06 on trajectory. For example a 150gr magnum load behind a 200 Shockwave launched at 2400fps will still drop about twice as far (25"+/-) and have little more than half the energy at 300 yards as a 180gr 30-06 launched at 2730. By comparison a 460 NE launched at 1470fps will have dropped about63"but have almost 200 fpe more than the SW. Few people would be trying to shoot that far but I use it as an example. Based on 100 yard zeros.