Heavy bullets, every time.
A local chap was at the range one day when the local Mounties were testing some vests.
They were shooting at the vest with their 9mm's and he asked if he could shoot one with his Marlin. They said yes, so he planted a 405gr. Remington SP at about 1,850fps on the vest.
They all walked out to pick up the vest and remarked as how the bullet didn't go through. Don noted, "you'd not have survived that hit, though. That shot even broke the 2x4 the vest was leaning against. Imagine the internal trauma".
I saw Don at the range a couple weeks ago, it's been a while. I didn't recognize him at first. His "boy" was with him and is now close to 40yrs. old.
Don does like his .45/70's and noted he now had 7 or was it 8?