A well set up rifled 12 gauge will kill a lot deader just as far as a 350/450 popgun.
I'd be hesitant on the "just as far".
The recoil differential is big.
The price per round differential is big.
If someone is going to argue on the "just as far", they really need to figure the cost per round in if they're going to PUSH the distance limits of the cartridge because they'll need the time spent verifying.
Dead is as good as deader.