You guys keep forgetting one thing.
If something huge happens, that puts the entire country in a "survival" mode, then there are going to be 300 million people, with over 150 million firearms, roaming around and shooting everything in sight. After 90 days, there are going to be NO deer to shoot. If you are reduced to shooting deer to eat, then everybody else is too, and they will be cleaned out in very short order. Heck, they were cleaned out of the entire state of Tennessee in about 10 years at the beginning of the 1900s, by just the mountain folks and pouchers who lived back then, and they were so scarce that hunting season was closed for decades.. The state were forced to buy two small herds from Alabama, and release them in Hardeman County, and a smaller county about 40 miles north of Memphis, and it took another 20 years before there was a huntable population again.
If you take a look at counties where cwd has been found in deer, and the state game department has ordered every deer in the county to be killed to stop the spread of the outbreak, it's only taken about 30 days for every deer to be killed. They are flat cleaned out in short order.
The same will hold true for rabbits, squirrels and other edible small game.
So this concept that you will just roam the woods like a mountain man and hunt your food, or stay on your farm and shoot the deer that wander through, is fallacious. More likely, you will looking for stray cats and dogs to eat. How's that .300 Blackout on cats at 300 yards? :-)
Most of the regular hunting cartridges are back on the shelves around here. The only rounds in zero supply are .22 LR, 9mm, and .308 Winchester.