Firearms? A nice 5.56 chambered rifle, ammo is cheap and will always be plentiful. Forget the stuff about “stopping power” - placement is king, capacity is queen, stopping power is a lowly duke. A decent hit with a 5.56 will kill or at least stop a BG.
Get an AK-47 style 5.56 - reliable as can be, and plenty accurate out to 50-75 yards with the iron sights (you don’t plan on getting into a shooting match beyond that, do you? That’s GTFO range). And pick up 10-12 extra 30 round magazines, and a few thousand rounds. Should set you back around $1200 complete.
Then go get a modern high capacity 9mm semi-auto pistol. Again, a 9mm will stop a man as well as a 40 or 45. Shot placement is king, and the smaller bullet not only makes high capacity obvious (over the 45s), but lighter recoil means faster followups for accurate use of that capacity. And the availability of 9mm ammo is huge - boxes of 100 for $20 at Walmart, every sporting goods store will have it in stock.
Remember: most gunfights occur at a distance of less than 20 feet, and even trained military and police miss with 70%+ of their shots. Capacity and accuracy win the day, especially if you only hit 20-30% of the time. The confident man will assume he’ll hit a better ratio; the wise man will assume worse. The dead man will assume he’ll always hit.
Anyway, get a good semi-auto 9mm; I’m partial to the current S&W Sigma 9s. The ones from the early/mid 90s had problems, but since 1999 and on they’re rock-solid. Because of the early reliability issues, they acquired a reputation, and thus are considerably lower cost than the equivalents from Springfield, Beretta, FN, etc. Right now, there’s a buy-a-Sigma get a pair of extra magazines for free deal. And having 17 rounds loaded and another 48 (3 more mags) on hand to hurl at the BG is a nice feeling.
Should be able to get the Sigma for $350. So that leaves you with plenty to buy more ammo, a good gun cleaning kit, shooting accessories (hearing protectors, glasses), and then spend lots of time at the range learning your firearms.
There's a reason that .223 is considered marginal for deer (you better get a solid neck shot), and is in fact illegal in many states. Our whitetails are small, and you won't get a shot here over 100 yards and 30-50 yards is more likely, but it's still a bad idea.
Even taking into account the question of divine intervention, remember that the Pope took 2-3 solid hits in the abdomen with a 9mm and walked away.