If you do anything with a firearm, you probably have the “perfect” ammunition for that purpose. It may be unsuitable for some or even all other purposes, but as long as you have a well stocked gun store nearby, who cares.
But consider a survival situation. What kind of situation, we don’t know, but one thing we can be absolutely sure of: there will NOT be a well stocked gun store nearby (for more than a few hours, anyway). This means, that the gun or guns you have for survival purposes need to use ammunition which is adequate for their purposes, you have a reasonable supply of and is common enough that your odds of finding more is not close to zero.
So what ARE the purposes of survival guns? Hunting for food (small game, medium game, birds and large game near and far), getting rid of varmints and pests, and protection (dangerous animals, people close by and people far away). In addition, ammunition can be used for emergency barter, and as a subset of the primary purposes, for training and practice.
What are the most common calibers, in the U.S. at least? Those would be 9mm and 5.56x45mm (.223), the current military pistol and rifle rounds. Which is sad, because the military versions of these seem to have been chosen by bean counters rather than firearms experts.
Although cheaper, easier to carry and ship and store and even shoot, they are not as effective as the calibers they replaced due to their smaller diameter bullets. These are, by international convention, “ball” rounds, or Full Metal Jacket.
But with modern versions of the bullets in these calibers, they can be made to serve. Besides, there is an awful lot of that military grade ammunition out there, and it is not useless. Other than the military, there are a zillion calibers in use by civilians. The most common “civilian” rounds are 22LR and 12 gauge shotgun.
22LR (Long Rifle)
This cartridge is good for small game but for every other survival use, it is significantly sub-standard. However it is cheap, small, light, low recoil, low noise and very common, so it is worth having a bunch. It is very useful for practice and training, and many defensive arms have a 22LR version or conversion kit available to assist practice.
In a SHTF situation, this ammunition may become a de facto currency. With a price as low as $0.04 a round, it would be wise to stock up. For hunting purposes, High Velocity Hollow Points are best, and for the best accuracy or quietness, Standard Velocity (sub-sonic) Target rounds fill the bill. Unlike most calibers, it is a RIMFIRE, which means it does not have a primer in the center, but primer material inside the rim all the way around.
9x19mm Parabellum (aka 9mm Luger)
This cartridge is supposedly a defensive cartridge. As used by the military, it has a pointy, fully jacketed bullet which does not have a reliable ability to stop an attacker, and when you get right down to it, that is the primary purpose of defensive ammunition. Because it is the most common military and police pistol and sub-machine gun cartridge here and around the world, and there are a number of excellent guns to use it, it is wicked popular.
Fortunately, there are effective (expanding) rounds available for it, which ARE more able to stop an attacker. What you are looking for is a JHP (Jacketed Hollow Point) which is “bonded” (the core is fastened to the jacket so they do not separate). Examples are Speer Gold Dot and Federal HST which may not be the “best” but are pretty good and the price is not outlandish.
At twice the price, Hornady Critical Duty (service pistols, barrier defeating) and Critical Defense (short barrel, no barrier) have the hollow point cavity filled with a polymer plug which is claimed to make them a tad bit more reliable feeding and expanding. This self-defense ammo test is a great resource to see how each round compares to the others available for sale to civilians.
There are technologies other than JHP, but they have not been proven yet, and the price discourages experimentation. A simple Jacketed Hollow Point will probably cost around $0.25 a round, with the Gold Dot or HST more like $0.40 a round and up. Military ball can be had for as low as $0.14 a round.
Bullet weights usually are between 65 grains and 158 grains, with the most common being 115 or 124 grains. I’d pick one of those (124 grain works better for me) and get some highly effective defensive rounds and a bunch of ball all of the same bullet weight and similar velocity (to have close to the same trajectory). Make sure that any hollow points feed reliably in your gun before getting a lot of them.
.223 Remington & 5.56x45mm (aka 5.56 NATO)
These two calibers are very similar, with the .223 being the civilian version and 5.56 NATO the military version. Unfortunately, they are not identical. If you have a .223 chambered weapon, you should use only .223 ammunition in it. The military ammo will fit, but has a slightly different dimension, and worse, a higher pressure.
If you shoot 5.56 NATO in a .223, it may work or you may have trouble getting the empty case out, which will disable the weapon until you get it removed. If you have a 5.56 NATO chambered weapon, you can also use .223 ammo in it, but will probably lose a bit of accuracy. There is a .223 WYLDE chambering which is the best in order to use both calibers interchangeably.
Stock up on the caliber which matches your weapon, and when you find any after the SHTF, make sure you know what you are getting. Personally, if I had a .223 chambered weapon I was planning to use for survival, I would exchange it (often just the barrel) for a .223 WYLDE chambering or at least a 5.56 NATO. These are all so close that attempting to rechamber a .223 to one of the others is likely to make things worse.
The primary uses for this cartridge are defense, medium game hunting and long range varmint control. As with the 9mm, the military rounds are pointy and fast, and they penetrate well; too well. As such, for their intended purposes, they are not optimal. They are, however, common, and have a low recoil, and many of the rifles which fire it are suitable for combat applications.
Fortunately there is ammunition which improves its effectiveness, which will run you from $0.35 a round to $1.00 or more. You can get cheap import JHP (or ball) .223 ammo for as low as $0.20 a round, but check out some in your gun before buying case lots, to see how well it works and how reliable it is. Military grade ball seems to go for around $0.27 a round.
Bullet weights generally are between 40 grains and 87 grains, but there is a problem. You need to know the “twist” of your barrel, because that determines which bullet weights should work “best” in your gun. If your twist is 1:7 (1 revolution in 7 inches), then you’ll get your best results with 69 grains and heavier, and you don’t want to go below 55 grains.
With a 1:9 twist, you will be happiest with 62 grains and less (great with the common 55 grain bullet weight), and should avoid anything above 77 grains. For versatility, my preference is 1:8, which works best with 62 grains to 77 grains, and will be adequate down to 40 grains and up to 87 grains. With this twist, in ball, I’m fond of SS109 (M855, Green Tip) 62 grain and try to match its trajectory to a 62 grain hollow point (Spear Gold Dot plus some cheap stuff). For varmints, I’d want a longer barrel with 1:9 twist and 50 to 55 grain varmint bullets. With an AR-15 platform, I could have one lower and two uppers instead of a separate gun for each purpose.
There is no gun which will “do it all”, but the 12 gauge shotgun comes close. With the proper ammunition, you can hunt any game and defend yourself. The only weak point is this is strictly a short range weapon. Not to mention that the ammunition is big and heavy and the recoil can be severe.
A pump shotgun is probably the best all around choice for survival. A semi-auto can compensate somewhat for the recoil, but costs a lot more, is a bit less reliable, and some models have part of the “works” below the barrel, which means you can’t put on an extended magazine tube, important for defensive use. You’ll want one with easily changeable barrels, and a short, cylinder choke (no restriction) barrel for slugs and defense, and a longer, multi-choke barrel for hunting birds and small game.
12 gauge ammunition is specified by the length of the shell in inches, the size of the shot, the amount of shot in ounces, and the amount of powder in “dram equivalents”. Back in the day when black powder was used, it was measured in drams.
Modern smokeless power then, is specified as providing the same velocity of the shot as the specified amount of black powder did (to help people transition from black powder to modern powder). Thus if a load is specified as being 3 1/4 dram equivalents, then the amount of powder in it will boost the shot to the same velocity as if there were 3 1/4 drams of black powder in there.
I’ve noticed that ammunition sold today sometimes has the velocity specified rather than the dram equivalent; I guess the black powder guys don’t need to be considered any more. In any case, you can usually tell at a glance whether a shell is “high power” or “low power” by looking at the brass base of the shell. If the brass part only reaches up about a 1/4″, then it is “low brass”; a light load. If it reaches up over a 1/2″, then it is “high brass” and will kick pretty good.
“Magnum” shells are even higher power; usually they are high brass. Common available lengths are 1 3/4″, 2 3/4″, 3″ and 3 1/2″. Most (modern U.S.) guns are chambered for 2 3/4″ and many are chambered for 3″. You can use shorter shells than a chamber is cut for although the greater the difference between chamber length and shell length, the more effect on performance it will have.
Personally, I’d prefer a 3″ chamber for maximum versatility, but would accept a 2 3/4″ chamber, and would mostly stock 2 3/4″ shells, as they have the best variety and most reasonable cost. In case you are wondering, the purpose of the 1 3/4″ shells is strictly to allow more to be carried in the magazine tube and they are only available in defensive loads.
Of course, you can get exactly the right load for any particular usage in normal times, but it would be impractical to do this when stocking for a disaster. You want the minimum number of different loads which will adequately cover the likely uses.
For small game and birds, a light load with #6 shot is the most versatile, although having some smaller #7 1/2 shot for such game birds as dove or quail would be helpful if practical. If you have a good chance of being able to hunt ducks, geese or turkey, there are additional loads you’ll need; be aware that they outlawed lead shot for hunting water fowl, so that messes up the ammo requirements we old timers are used to (because lead and steel don’t fly the same). Shells with 1 oz or 1 1/8 oz of #6 shot run about $0.22 each and up; #7 1/2 shot seems to be a few cents cheaper per shell.
For hunting large game, slugs are optimal. These are usually “high brass”, although they do offer “reduced recoil” loads these days. Keep in mind that the shotgun bore is smooth and so does not impart any rotation to the slug. This means it does not have gyroscopic stability, which results in less than stellar accuracy. You can get “rifled” slugs which improve the accuracy a bit, or get another, rifled, barrel just for slugs.
Unless you do a lot of big game hunting with a shotgun, the additional barrel is probably not worth the effort. The other option is “sabot” slugs, which are smaller in diameter, encased in a plastic sheath which falls away when you fire it. These slugs may be lighter and have a more aerodynamic shape, so are more stable, giving you better range or possibly trajectory than a normal slug. Rifled slugs go for around $0.60 a round and up, and sabot slugs start around $0.80.
Slugs can be used for defense, and there are even some specialty slugs for maximum effectiveness… and maximum price. Generally, however, Buckshot is optimal for defense, and for that matter, decent for hunting (the “Buck” in Buckshot refers to a male deer). As with slugs, these are high brass; you may find some “reduced recoil” versions, but the selection and price are not great.
Generally you will be steered towards #00 Buck, by people educated by TV and the movies. It will work and may be more available, but with only 9 pellets in a standard load, it is not the best choice. That would be #4 Buck with 27 pellets. Expect to pay $0.30 and up a round.
So far we have a good selection of common ammunition which can meet all our needs, except long range. Handguns are generally best under 50 yards. A 12 gauge with Buckshot is also best under 50 yards; with a slug good up to 75 yards or 100 yards if fired from a rifled slug barrel. A .223 with 16″ barrel will reach out 300 yards, or with the correct barrel and ammunition, perhaps 600 yards or even more, but it is not really effective against man or large beast.
We need to add a big bore, long range cartridge to the list to be considered. There are many effective cartridges which would serve, but for versatility and availability, it would be hard to surpass the venerable 30-06. This round will do anything you need a large rifle cartridge to do (in the U.S.; its not a good choice for an African safari), except it’s too long to work well in a semi-auto combat rifle, with the obvious exception of a M1 Garand. Otherwise .308 Winchester/7.62x51mm is a good alternative, designed to have nearly the same ballistics in a shorter, self-loader friendly cartridge.
As with the .223/5.56 NATO pairing, these are also a civilian and a military pair, which are similar to each other but not identical. In this case, the military version is the lower pressure one, with thicker brass and a bit longer headspace. Thus you can fire the 7.62 NATO ammo in a .308, but if .308 is fired in a 7.62x51mm (aka 7.62 NATO) chamber, there is a good chance the brass will rupture.
The .308 chambering would seem to be a better choice under most conditions. If you have a 7.62 NATO chamber, you can measure how dangerous it would be to fire .308 in it by using a set of .308 headspace gauges. If the bolt closes on the No-Go gauge, the brass will probably be over stressed, while if the bolt closes on the Field gauge, it would be risky to fire .308 rounds in that gun.
If you will be using it in a bolt action rifle, 30-06 is a very good choice. If you want to use a semi-auto, .308 may be a better choice, but if you do go with .308, you should consider also having a bolt action rifle for long distance accuracy. Think counter-sniper. Bullet weights vary from 100 grains to 240 grains, with 150 or 165 grains being good choices for defense or deer, and heavier bullets like 180 grain suitable for larger game like elk or moose.
For large, dangerous animals such as grizzly bears, 220 grains would not be too much. Quality ammo starts around $0.60 a round, with the fancy hunting ammo over $1.00 a round. You can get cheap imports and military surplus, particularly for .308, as low as $0.30 a round, but try it out in your gun before committing to it.
So far we have looked at the best choices giving good service with top availability (#1 most popular handgun caliber, and the three most popular rifle calibers, all of which are, or used to be, U.S. military calibers). Of course there are alternatives for some of these, with decent availability if any of the top choices are not desired for some reason.
For defense with a handgun, .45ACP ball is more effective than 9mm ball and is fairly available (ex-military caliber, #3 on the handgun caliber popularity list). Alternatively, in a revolver, .357 Magnum (#2 in popularity) is pretty good, not only for defense but decent for hunting, and can also shoot .38 Special which if using a light target load is great for small game.
If the 12 ga is just too much to handle, 20 ga will do much of what 12 ga will do; not as well but adequately.
The Russian answer to the 5.56 NATO is the 7.62x39mm. It’s a more effective round close up, and at the current time there is plenty available and much of it is cheap in cost. Whether it will be available in a SHTF situation is unknown; it is only #9 on the rifle cartridge popularity list. In the same performance class as the 7.62×39 is the 30-30. It is very popular for deer hunting (#4 on the rifle caliber popularity list), so you may find some at places when nothing else is available. And the lever action carbines which shoot it are pretty sweet and can even be used for defense in a pinch.
As for 22LR there really is no alternative; everything in its class is more expensive and is not particularly popular, so availability will be low. Looking at 30-06 and .308, there are a lot of calibers in their class or even higher, but none of them come close to the availability of those two. A decent round with fair availability might be .270 Winchester, #5 on the rifle cartridge popularity list.
Our primary goal has been to consider those calibers which are adequate for a variety of survival purposes AND are most likely to be available during times of crisis. If there is a caliber which is significantly better, or you already have, that you like in place of or addition to, any of these, it is certainly an option to stock up on that caliber.
Just keep in mind that when you run out of ammo, your gun becomes a finely machined stick or rock, or if you desperately need something and the person who has extra cannot use the ammo you have, a satisfactory exchange is not likely.
Ammunition tends to be fairly pricey these days, so although going to the gun store to get a box may be convenient, it often is a poor choice for buying in quantity. Of course, you can always talk with the person in charge and see what kind of deal you can work out, but usually you will be best served by finding good deals online. This methodology may also prevent you from being charged sales tax.
On a daily basis, you can get an idea of the current market by using ammoseek.com; however, these are usually not the best possible prices. For that, you need to get on the mailing list of several suppliers and wait for sales. Be careful; ammo is heavy and shipping costs can sometimes turn a good deal into a not so good one.