What miraculous change was made to the post-72 Marlin 1895 45/70, that prompts Buffalo Bore Ammunition Co to specifically state that some of their ammo should only be used in said guns?

https://www.buffalobore.com/index.php?l=product_detail&p=328


I never thought I'd grow up to be a grumpy old man, but I did, and I'm killin' it.