In reality there are several changes from the original. The cosmetic "dimple" (HP) being the most obvious and least influencial.(Marketing at its' best). The lead composition has become a bit more malleable so as not to separate in two during its' pass down the bore under pressure. The original was so hard it would make wheel weights seem like putty (Police version). The sabot however is now softer as well with a reduction in velocity of about 100 fps. Originally available in reloader packs with Red straight walled hulls (cheddite ?) and white sabots they never shot as well as the factory ones. The version marketed by S&W had a modified hard alloy, no dimple with a BLACK sabot, again cosmetics. Finally a plastic plug replaced the original wood dowel plug in the original. They found that the wood did not hold up under firing pressure and the plastic popped out easier after leaving the barrel. Even with all that said I do not think these are really that great of an expansive slug. They will however leave a neat .45 cal + hole in both sides of a deer. Aerodynamically you can see where LYMAN got some of their design ideas along with airgun pellets. It will also tell you why proportionately the 20 ga. flies truer at longer ranges than the 12ga.