Until you actually shoot it, you won't know how good it is.
Bring a light and a small mirror with you (like a dentist's mirror) so you can at least examine the bore to see if it is clean and shiny with no pitting or rust.
Handguns (pistols and revolvers) are primarily defense weapons, always have been, always will be.
If you actually live in grizzly country, then a 45-70 or a 500 makes perfect sense.
If you want to try hunting with one, then a 454 or 44 makes sense instead. The 454 and the 44 are extremely accurate, moreso than the 45-70 and the 500. But the 45-70 and the 500 pack a walloping punch at closer range.
For any other handgun applications, non-hunting or non-grizzly, the 10mm or the 45ACP are much better choices, for defense against people. I know one guy who is so paranoid that he owns a 357 Desert Eagle. For me, the 45ACP is fine though.