Kostya

Ok, a few more considerations I have been ruminating upon concerning all this.

Sorry by the way to all the non-zombie movie nerds out there. There's actually a reason behind this you know, beyond just run of the mill curiosity, but I digress.

Anyhow.

I can think of a few ways the amount of ammo in the US could be significantly reduced in the months following a zombie apocalypse:

Obviously massive amounts of ammo would be present in cities, but I think it's safe to say that it is unlikely that people got their shit together in under three days and managed to escape the zombie hordes with significant amounts of ammo. I mean, straight off the bat, the advice would be stay inside your home. So, a hell of a lot of well armed suburban fortresses would spring up right there. These people would be working on the presumption that any second the military is going to subdue the zombie hordes, and they just need to hold out for a few more days. Days go by, these people begin to get a bit hungry, thirsty, overwhelmed by zombies. Gun store owners, or squatters would be impregnable to zombies, assuming that they had security bars and the like, which your average gun shop has (right!?). But over time, starvation, desperation, or thirst is going to kill these people. They die, their ammo stores are inaccessible as a result, oases of ammunition in a sea of zombies that nobody can penetrate.

So straight off the bat, there's a lot of ammo that's basically going to be locked down in zombie infested cities.

Same goes for the country, with the exception of bomb shelters, I can't really see the country being too much different, apart from the fact that some people might have time to construct rudimentary defenses. The same essential problems arise: food and water, and I can't see them being solved easily. Now, as opposed to the cities however, a farmhouse is pretty accessible for a thoughtful scavenger, BUT, they also need the means to move the ammo to a more suitable place with food and water, something which would again be difficult in a bandit infested, zombie ruled dystopia. I think the most likely places to flourish would be isolated structures that act as natural citadels: prisons, factories, industrial buildings.
The only other place I can see lasting longterm is a bomb shelter, which can be eliminated in terms of ammo, since the people stuck in them aren't going to open up, they're not going anywhere, and their resources aren't circulating in whatever economic structures that might exist afterwards.

The other major issue would be that all this ammo would be destroyed fairly quickly in the years following the outbreak. Sure, it will last for a long time if undisturbed, and undoubtedly some ammo would still be preserved indefinitely in bunkers etc. However, I think fairly quickly a lot of material destruction would occur that people don't factor in:
Fire, no fire brigades to prevent them or contain them. Zombies are clumsy and essentially I think the outbreak of a fire in or near major cities in the weeks following would be pretty high. Not to mention fires inadvertently started by survivors who are camping in the forests, a forest fire with nothing in its way would rip through a hell of a lot of farmhouse. Kaboom, say goodbye to a fair few ammo caches in the countryside. Say goodbye to a lot of vehicles, fuel and food too!
In fact, as months stretched into years, with nothing maintaining them, the cities would crumble pretty badly, wind, storms, fire, flood, rain, zombies, early looting, earthquakes, all this damage would compound, as opposed to being cleaned up. Think about how much ammo would get hosed down after the first hurricane hit Miami or Jacksonville. Think about all the ammo that would get rained on after an earthquake in LA, think about how snow build up, and presumably break down houses up in the Rockies without maintenance. Think about how vegetation would break up houses as they grew into them over the years. All this is going to expose ammo to rain, snow, fire and the rest of the elements, and wreck a hell of a lot of it. Other problems would be finding ammo hidden in bunkers, it would seem like a giant gamble to spend days trying to get inside a reinforced bunker, or hoping you'll stumble across a well stocked bomb shelter. I think that pretty quickly, a lot of manufactured good would be gutted by the material destruction of the elements left unchecked and untended.


Reloading your ammunition:
The problem I see here is essentially twofold:
Number one, collecting the materials you need. Frankly I don't think it's likely that people are going to have the vision or the capacity to consider this move for quite some time. It would be difficult, though not impossible to access sulphur and nitrate, but even so, I think it would be rare for someone to have immediate, ongoing access to all three ingredients. In addition, you obviously need a bullet, lead I presume, I'm not sure where these come from or how hard they would be to come by, but they might be difficult to find.
Number two: It's not worth the effort. This seems a little stupid, but I really think that's the conclusion most people would come to. The ability of one person to produce gunpower would be rather small I presume, and the process would take some time if Clyvre's info is correct. Now, this guy has to eat and drink. Now, he might be able to procure food and water AND still make gunpowder, but certainly some of his labour has to go into gunpowder production. Now, if its true that they would have to go mine sulphur out of the earth, presuming they could find it, and then synthesise nitrates as well, it would probably not be worth one man's time, since the amount of gunpowder he could produce wouldn't really be enough (I don't think, maybe I'm wrong), given he also then has to procure bullets, or bullet like objects, and construct each cartridge, individually. Sounds like an awful lot of work. Now, a bandit group might roll up, having pillaged the hell out of a few other small groups and just take said gunpowder thanks to their massive numerical and military superiority. I mean, how many shells could one guy make? Surely not that many. I think people would be more interested in food production, basically they're living in a subsitence situation, and there wouldn't really be much excess labour for extraneous activities like that.
However, maybe after they established themselves, a community of say 100 people could afford to produce gunpowder, with manual production, I don't think they'd be able to manufacture enough to make it worth their while, whereas other weapons could be used multiple times: arrows, chopping weapons, spears etc.
This is not to say that it's not a possibility, but I think that there are some objections to it being a widespread practice.
Let me break it down another way: You've got a tiny minority of humans, starving, fighting amongst themselves and hugely outnumbered by zombies. Frankly I don't see it being very likely that this tiny amount of labour could manually produce enough ammo to repel vastly superior numbers of undead, the economics of it simply don't seem right to me. However, I might be wrong, is it possible for to produce huge amounts of ammo using simplistice, non industrial methods?

Sorry if I'm getting a little involved for you all, maybe we should move it so the boffins and Knowedge can argue about it. Then again, you Weaponry people sure know a lot about guns.