So let's take a step back and think about why you'd want to stockpile ammunition in the first place:
- Hedge against supply shortages (either normal or TEOTWAWKI-induced) or government bans
- Hedge against price increases
- Barter
- Convenience; not having to run to the gun store and buy ammo for each range trip
- Have enough ammo on-hand to defend yourself
Ammo Hedges
Hedging, either against shortages or price increases, can be thought of as an investment. Buy tangibles, as Rawles says. If there's either a shortage or a price increase, the value of your ammo will increase. At that point, you could either sell it for a gain, or shoot it and avoid buying the higher priced new stuff.
You would hedge, generally, the ammo that you would shoot in a practice/training session. You aren't burning through massive quantities of ammo defending yourself, you're doing it at the range. Aside from being an investment, your hedge ensures that you will always have ammo on hand to practice with, no matter what.
I doubt people will be doing lots of training post-TEOTWAWKI. Some certainly, but not a lot. Ammunition will just be too valuable, and training harder and more dangerous to organize. Barter would then be the primary use for an ammo stockpile in a TEOTWAWKI scenario. Your ammunition investment will definitely increase dramatically in value post-TEOTWAWKI and would be a very valuable resource.
Notice a trend? A large stockpile of ammunition is an investment. Once you get beyond a realistic "defense" stockpile and a realistic "convenience" stockpile, you're getting into investment territory. You're betting that there will be supply shortages or dramatic price increases in the future. If you're wrong, and ammo is always available, and at lower (or the same) prices, then your investment won't pay off (except for peace of mind). Unlike a company's stock though, ammunition will always have some value, and is unlikely to decrease dramatically in value.
If you look at a big ammo stockpile in that way, the "how much" answer becomes fairly clear--it depends on how much you want to invest. I'd start by taking a look at how much ammo you shot last year and go from there. I would also note that it can be difficult to sell off massive quantities of ammunition - finding buyers, shipping ammo around, etc. so if you're planning on investing a lot of money into ammunition, keep that in mind.
Thinking of the big ammo hoard as an investment helps you to sort out its importance. Essentials come before investments; there are a lot of other things you need squared away before you start putting back cases and cases of ammo.
"Convenience" Stockpile
Going out to the store and buying ammo before every range trip is just plain wacky. Having a stash of range ammo at home is a convenient and prudent thing to do. You're not investing at this point, you're buying to have it for convenience, maybe to save a few bucks when you find a good deal, or maybe to get a specific hard-to-find kind of ammunition that you like to shoot.
To get the number, I'd take a look at how often you go shooting, how much you shoot during a range session, and how often you're in gun stores or ammo sellers. Pick a time window that you're comfortable with and go from there. For example, if you go shooting once a month and shoot 200 rounds of Wal-Mart Federal .223 at each range session and go to Wal-Mart on a weekly basis, you'd be fine with probably 600 rounds of the stuff on-hand. If things continue on normally, then you can buy a box of ammo every month during one of your Wal-Mart trips. If there's an interruption in Wal-Mart's ammo supplies, you have three months to find an alternative source of ammunition. If, after those three months, you're unable to get replacement ammunition anywhere at a price that you're willing to pay, then you probably won't be going target shooting anyways. If three months of uninterrupted range sessions isn't enough, go further.
Defensive Stockpile
This is the real meat-and-potatoes here, the ammunition that you want to have around for serious use, either hunting animals or shooting bad guys. This isn't an investment or a matter of convenience, it's an essential.
How much of this ammo do you need to have on-hand to defend yourself? How many firefights are you going to be getting in? For how many months or years without re-supply?
Most people, even those in crap-hole 3rd world countries, working dangerous jobs, don't find themselves in many firefights. Most of us don't get into any gunfights, even after major disasters. You would certainly want to have enough ammunition to load up a set of magazines--however many you've decided is your defensive loadout. If you did get into a gunfight, blow through most of your ammo and survive, you'd want to be able to reload your empty magazines, so you would also certainly want ammo to do that. Probably three or four times over.
If you've gotten through four or five magazine-dumping gun battles, lived to tell the tale unscathed and run out of ammo, well, you're pretty fortunate. You've also probably got a few battlefield pickups in your possession. Or maybe you have to move to alternate weapons, barter for ammo or whatever.
Really, I'd pick the number of times you want to be able to replenish your combat load and then add one more to that. Three or four is a good place to start, because hey, you never know. If you reasonably think you may be in a dozen or two dozen such gunfights, without an opportunity to re-supply, then you should stock ammo accordingly (or perhaps re-think your strategy).
So, if you had a combat loadout of six 30-round magazines, plus one in the gun, each loadout would be 210 rounds. Having that four or five times over would give you 840 to 1050 rounds, which should be more than enough for any combat you'll ever need to do. If your loadout was four mags, plus one in the gun, each loadout would be 150 rounds, and 600 to 750 rounds would be a pretty good defensive stash.
If you plan on using your fighting rifle for hunting, I'd add in some hunting rounds as well. You don't need a lot of hunting ammo, and combat ammo will work on big game as well, but if you're going to be using the rifle in that capacity, you should add some ammo to the stash. I'd pick a number of months you want to be able to hunt for and then add ten to twenty rounds for each month - more if you're an experienced hunter, located in a rural environment with lots of game, less if you're none of those things.
Finally, it's probably not a bad idea to have some extra ammo stashed/cached off-site. I'll let you decide on that, but I think a few ammo caches could be pretty smart and fall under reasonable defense use.
Example
So, let's say I run an AK-47, with a Glock 19 backup. My loadout for the AK is four magazines, plus one in the gun, and my loadout for the Glock is two magazines plus one in the gun. I want to be able to load all of my magazines four times (SHTF load + three full mag reloads). There's potential for some limited hunting in my area as well, and I'd like to have 6 months worth for my AK, just in case. My defensive stockpile should have:
- 600 rounds of combat 7.62x39mm (30 round magazines x5 magazines x4 loads)
- 180 rounds of 9mm (15 round magazines x3 magazines x4 loads)
- Plus 60 rounds of hunting 7.62x39mm (6 months at 10 rounds a month...dunno if they make a 'hunting' 7.62x39mm round)
Shockingly small compared to what many in the survival community would recommend, I know. But once you get beyond enough to reload your combat load a handful of times, you're getting away from plausible defensive use and into investing in ammo.
Simple Rule of Thumb
If you're lazy and don't want to do some simple multiplication based on your combat load, a simple rule of thumb to go by is a case of defensive ammunition for your fighting rifle, half a case of defensive ammo for your handgun. A case of practice/convenience ammunition for each would also probably be good enough for most, unless you head out to the range quite often or routinely shoot large volumes in competitions or training.
There you go!
So there's the TEOTWAWKI Blog answer to the age old question of how much ammo does a survivalist need. Once you get beyond basic stockpiles for defense and convenience, you're getting into investing territory. There's nothing wrong with that at all, but it needs to be thought of and prioritized as an investment. Make sure you're squared away in other, more essential areas before you start venturing down that path.
Multiple Weapons
If you have multiple fighting rifles--for instance, you and your wife each have an AR-15 for defense purposes--then each rifle should have ]its own stockpile of ammunition.
Simple Rule of Thumb
If you're lazy and don't want to do some simple multiplication based on your combat load, a simple rule of thumb to go by is a case of defensive ammunition for your fighting rifle, half a case of defensive ammo for your handgun. A case of practice/convenience ammunition for each would also probably be good enough for most, unless you head out to the range quite often or routinely shoot large volumes in competitions or training.
There you go!
So there's the TEOTWAWKI Blog answer to the age old question of how much ammo does a survivalist need. Once you get beyond basic stockpiles for defense and convenience, you're getting into investing territory. There's nothing wrong with that at all, but it needs to be thought of and prioritized as an investment. Make sure you're squared away in other, more essential areas before you start venturing down that path.