Yes, it's straight walled. Some states limit handgun cartridges by case length which eliminates anything, but magnum revolvers. I haven't tried hunting deer with my .45. I think it'd be best inside 25 yards and, frankly, I have better, more powerful handguns for the purpose starting with .357 Magnum. The .45ACP is what it is, but it's not really a hunting round, though I'm sure you could take deer with it at short ranges using +P loads.
My P90 is quite accurate, but my .45 Colt Blackhawk and .357 Blackhawk are more accurate and my contender is the most accurate and what I'd shoot at woodchuck with, maybe buy a .223 or hornet barrel for it. Actually, I prefer it for deer and hog, too, with the .30-30 barrel attached.