Hmmmm, a High quality 5.56 Piston Driven AR, a lighter weight 6-8lb short mag like a 6.5 PRC or 300 WSM, and a 870 Pump in 12 Gauge. I can hunt Predators and Prairie Dogs with the AR, I can hunt every deer type critter in North America with the short mag and then do plenty of wing hunting with the 870. Plus, the AR is good Zombie medicine.
If it where just rifles. 22 LR, 6.5 CM, and 30.06.
just long guns... 22LR ,12 gauge 870, and 30.06
But we all know the 6.5 CM can do everything so I would only need one.