Mr kemp. yes well when you find the very rare and elusive milk jug whitetail deer let me know.
and a 45-70 is a rifle cartrige yes? so id hope it would go through a milk jug
and yes it is a matter of penetration. you can stick a pencil through drywall with relative ease now with the same force try and stick you index finger through the same drywall, and youll probably break it.and barely leave a mark
personally id rather be sure to puch a hole in something with a smaller round rather than try to shoot a projectile 3 times the size and not make it through
a real world example of this is...
when i was about 8 or 9 my nieghbors cat was killed by a racoon so he puts some bait out(cat food) and waits with his baretta, he shoots a racoon right between the eyes and it just got angry and took off so he grabs his ruger .22 and drops it with one shot right behind the ear. still in the skull probably not as thick as the forehead but still solid bone. i dont know if it would have gone through the spot where the 9mm landed, but it seems to prove the point.