For reference, I could tell you where to find a bait shop with a picture of a 17ft from Lake Monroe. Two hunters laid next to it, head to toe + head to toe and the gator was still bigger! State wildlife officer did not measure so it's "unofficial", but the pic is proof enough for me!
Seriously, If there was a nuclear war and everyone had to go back to a Stone Age existence, I imagine the swamp people would just keep on living like it was just another day in the woods. Those people know how to hunt.
Firearms Firearms (except shotguns) may be used to dispatch alligators while on hook and line (see Fishing Method above) or to harvest free swimming alligators. Harvesting free swimming alligators with firearms may increase chances of losing alligators. Extreme caution should be used when harvesting free swimming alligators to ensure that alligators can be retrieved once harvested. Alligator hunters should practice firearm safety at all times and pay close attention to ricochet hazards. Harvesting free swimming alligators may not be permitted if hunting on public lands or public lakes.
http://www.wlf.louisiana.gov/alligator-hunting-regulations-overview