You're right. I did not mean that a 250 grain bullet is the equivalent of a 500 grain bullet. I don't think it is.
What I meant was that the principle of a large, heavy, penetrating bullet at low-to-moderate velocity is well-proven.
Note that a .45-70 in the hands of someone who can hit a target at distance can drop a bison at a few hundred yards, no problem whatsoever. By then, it's poking along. At 100 yards, the bullet will go right through and kill the buffalo behind it.
(No, I didn't just read this stuff in a book. I'm having black-powder-tinged buffalo spaghetti tonight as a matter of fact.)
We're talking about an animal that's 1/10 the size of a North American Bison, at 1/10 the range, though. A hole-puncher .44 round will do its job.
A Black Bear is also not an elephant, rhino or a cape buffalo, or anything else better suited to one of the big Nitro Express rounds. But they still operate on the same principle: big, heavy, solid bullet, deep penetration.
The .44 isn't equivalent to the .45-70; my point was just that the principle by which it works -- within the parameters in question -- is well-proven.
IMO it's the hollowpoints that we've learned to trust for home defense that we need to avoid for woods defense.