Winchester 73

[Nuclearcricket]

This may seem like a bit of a stupid/silly question, but its bothering me so I thought I would toss it out and see what you all think.
Since it seems that Lyman molds (and Ideal for what its worth) seems to have been introduced to the world by dirt, they would know what was good bullet for the older calibers like the 44-40 and such. If they made molds that were correct for those calibers back in the day when they were the calibers in use why did they change things over the years and people had to do deep dives and do redesign to make bullets now that work well and make guns shoot today as they should have shot back in the day?
The John Kurt mold seems to be the bullet of choice any more for the 44-40 and its on my wish list of molds to try. Kind of seems to me that if that mold works well in the 44-40 I would think it would shoot well in any of the modern 44's from the Russian up to the Mag. Has anyone dipped their toes into those little ponds of water?
Sam