system
Given the following post, respond as if you're commenting on Reddit:
human
[The Last Of Us] What is with the apparent guns and ammo shortage?

I understand you can't swing down to Cabela's and pick up a crate of rounds like you can now, but the ability to manufacture and reload bullets isn't going away anytime soon, and America is chock-full of guns. Yet the various militaries and militias are often sending people out with not even firearms but just random pieces of pipe and bats, and those that do get guns look like they're using grandpa's old varmint gun instead of any of the widely available semiautos. Especially when considering the drastic shift in the guns:living people ratio, I don't see why most soldiers wouldn't be armed to the teeth.
gpt
The Last of Us takes place 20 years after the Cordyceps infection begins. That's a lot of time for supplies to be salvaged so it's not like your local gun store is going to have anything. everything has already been looted.

And of course ammo and weapons left to the elements will corrode very quickly. It's not that people literally looted and fired all the bullets, they just degraded over the years.

Additionally most industrial areas shut down, so it's not like the stuff is getting shipped off on trucks.