Ben,
This is not my experience, just some I find on another forum:

My Kodiak 72 is a shooter, 80 grs GOEX and PRB prints 1.5" horizontal at 75 yards. I have killed buffalo at 100 yards, both balls passed completely through, both hit ribs, with 90 grs GOEX 2f. That's enough penetration. A friend who likes to see how much powder he can burn, has settled on 110 grs as a practical limit-nothing to be gained in his opinion in burning more powder.

Martin