If you are new to firearms, you are probably wondering “so what’s up with all the bullet sizes & all those codes?” Never fear, we’ve got a few simple answers for you to get you started.
Over the last 150 years, there have been thousands of manufacturers of both firearms and ammunition, however the basic overall designs have remained fairly similar. For this article, I am going to keep to the very basics, the “need to know right now” stuff and I am sure there will be purists out there who will have heart attacks over my generalizations, but I would rather have you “on the right track” than “buried in the details”.
Let’s split this into two parts, solid-case shells and shotgun shells. First, let’s look at solid-case shells.
About 150ish years ago solid state shells started coming onto the scene in numbers. At the time, propellant was “black powder” and guns were loaded (generally, with a few exceptions) by pouring powder down the barrel, ramming home a ball, putting a percussion cap on the firing mechanism (or a flint before that… as well as older designs using such things as slowmatch). Pull the trigger, cap (or spark) hits powder through a priming hole, and gun mostly went BANG.
The first case shells used black powder as well. Early on, there was very little standardization outside of the militarizes, but after a few years common sizes started to develop making pre-manufactured ammunition much more viable.
During the 1890’s, a few of the rounds we still have today were starting to come into play… rounds like the .38 Special and the .22 date back to this time. Other rounds of the time that are still around include the .45 Long Colt, for example. These rounds used black powder, but about that time a new type of powder (one that is much more explosive) was coming into use, commonly known as smokeless powder.
This only really matters today in one situation, if you buy a gun designed to use black powder you ABSOLUTELY CANNOT use smokeless powder, it will probably explode on you if you do. Beginning preppers should not be buying black powder guns anyway, but I wanted to mention it.
Rounds continued to be developed and improved, but guns last a long time so that’s why a lot of the old rounds have stayed around. Magnum rounds were developed, basically rounds of the same caliber but with more “oomph” behind them (higher pressures spitting the bullets out faster).
Additionally, manufactuers from all over the world made their own sizes and cartridges, so that leads us to where we are today… with a million confusing choices.
OK, well it’s time to get right down to it, let the rubber hit the road.
Let’s talk about what some of these terms mean.
First, let’s talk center fire vs rim fire. Basically, when you pull the trigger, a firing pin in the gun strikes the back of the round with a lot of force. Center fire bullets have a primer in the middle of the round, when the firing pin hits the primer it explodes inside the shell and causes the powder to go off. With a rim fire round, a primer coating is “painted” on the bottom of the round in the rim, and when the firing pin hits the rim, it ignites the primer which explodes and ignites the powder which sends the bullet down the barrel. Importantly, rim fire rounds have a much higher failure rate than center fire, which is why center fire rounds have mostly taken over, leaving only two popular rim fire rounds, the .17HMR and .22, neither of which is appropriate for self defense.
Caliber: It’s simply the diameter of the bullet, in inches or millimeters. Probably the most common caliber is .30 (7.62mm if you are using metric measurements). There are small variances, but pretty much anything in the category .38 & .357, .30-06, .308 are a type of .30 caliber rounds.
Other common calibers are .17, .22, .380, .40, .45, etc. I won’t go into all of them but suffice to say the higher the first number, the bigger hole they make going in.
Got it?
OK, now we have a couple of other important measurements to know. One of them is bullet weight, and these are given by grains. The more grains, the heavier the bullet. The other is the amount of powder, again in grains. The more grains, the more powder you have.
At this point in time, it’s not important for you to understand bullet and powder grains, but you will probably see them on the box,
Next up is bullet types. All bullets are not created the same, in fact they are radically different. To be clear, I’m talking about the actual bullet, which is a part of the shell. The shell has either three or four basic components (depending on which type it is). Remember, a center fire shell has the primer (the dot in the middle of the bullet), the shell casing, the powder and the bullet. Rimfire rounds have the primer inside the rims, so they only have the shell casings, the powder and the round.
There are many types of bullets designed for many different jobs. I’m only going to give you a few because, frankly, this article would be WAY too long to keep anybody’s interest if I didn’t. Let’s start with Full Metal Jacket (FMJ). A LOT of FMJ rounds are sold in the US, especially for military caliber guns. An FMJ bullet is a soft core (usually lead) encased in hard metal like copper. Sometimes FMJ’s are steel-cored (and gun ranges REALLY don’t like those because they tear up the backstop). FMJ rounds do not expand, they just poke holes through what they are hitting. Why would you want to do this? Well, countries that signed the Geneva Convention are required to use jacketed rounds and not hollow points. They are also cheap to produce and fire well through just about any firearm. They are not a good choice for self defense generally (yes, I know the penetration arguments, this is a primer… give me this one, you experienced people!). Most places it is illegal to hunt with FMJ rounds. FMJ or other types of jacketed rounds are commonly called “ball rounds”.
All illustrations below are from Freedom Munitions, they do not sponsor us but we highly recommend them and they are Salty & Spice’s go-to online ammo supplier.
Non-jacketed .38 Special rounds
Full Metal Jacket .38 Special rounds
Next up are hollow points (HP’s), which are designed to expand causing great traumatic wound cavities. There are half-a-million variations on hollow points, but suffice to say that they are the types of rounds you want to have around if the Stuff Hits The Fan (SHTF).
Hollow point .357 Magnum rounds
Hollow Points (with poly filling for ballistic purposes) in .223
That’s where I’m going to leave it. Yes, there are many, many other types of bullets, but this is enough to get you started.
When it comes to shotguns, the sizing system is really strange. If you read “gauge” on a shotgun, that (when used properly) goes back to the ancient English measuring system of the number of balls in that “gauge” that it would take to make up a pound. In other words, it takes 12 small cannon balls to make a pound’s worth of weight in iron. So, it’s a inverse to caliber, the smaller the numbers, the bigger the bore. Thus a .20 gauge is smaller than a .12 gauge.
So, following that logic, a .410 must be the biggest of them all, right? Nope. I told you it was really strange. For some reason, .410 shotgun shells are in caliber, not in gauge. Who knew?
All shotgun shells are center fire, the only real difference is what the “load” is. Basically, there’s several types of shotgun shells. First, there are slugs, designed for hunting (they do make a really heavy hitting self-defense load) game like deer. Then there is shot. Again, the smaller the number, the bigger the shot. OO (double aught) buckshot is big, and it’s followed on down the list by #2 shot, #4 shot, etc.
The good news for beginners is that shotgun shell boxes often say on them exactly what they are for.
That’s a basic overview, hope it was helpful!
Salty: With all due respect. To dismiss the 22lr. as a survival and a self defense caliber demonstrates your lack of knowledge of the history of the 22lr. many other people have the same problem. ( Bigger is always better ) NOT!
My Father was born in 1919, He told me that when he was young he shot and killed over 100 Deer. His hunting rifle was a 22cal. bolt action. he told me he could kill any thing that walks the north American content with a 22lr.
There are many videos on line on the 22cal. look at some.
I read a magazine article the talked about the largest Grizzly bear ever taken in Montana with a fire arm was killed with a 22cal. rifle.
I saw a video of some one shooting 5, 1 gal. milk jugs with a 22lr round nose led bullet. filled with water. it went though all 5.jugs. he then shot them with a hollow point. the first jug exploded and put 3 small holes in the 2nd jug.
another video some one shot a hole in a 1/2 inch sheet of ply wood at 440 yards.
I could go on and on about the 22cal. but I will say if I could only have one gun when the SHTF please let it be a 22cal rifle.
It’s not a lack of knowledge of the .22’s history, I don’t in any way discount the value of the .22 round as a valuable hunting gun.
I just don’t think it’s a wise choice for a primary self defense weapon. Will it kill people? Certainly! But that doesn’t make it a better choice than something like a 9mm, .40 S&W or .45ACP in a handgun, because all of those rounds are 1) much more reliable in a semi-automatic handgun and 2) leave a much bigger wound/shock cavity area.
I’m not saying don’t own a .22, but I am saying that using a .22 for anything other than hunting small game is not ideal.
Thanks for your thoughts and sharing your views my article… differing views are great, people can make their own decisions based on the various ideas!