The ammunition you buy makes a real difference in the way your gun performs. New gun owners can be forgiven for thinking a 9mm is a 9mm, and that one box of ammo is as good as any other.
Experienced gun nerds know better, and regular shooters know that they get wildly different performance from their guns depending on what kind of ammo they're feeding them.
Knowing your ammo is part of becoming a better shooter, so here are five tips for doing it right.
1. Know Your Calibers
Here's a fun experiment you can try: Go into the biggest gun shop you can find, one with a really big selection, and ask for "9mm."
In the United States, the odds are that you'll be handed a box of ammo with something like this printed on the side:
- 9mm Parabellum
- 9mm Luger
- 9mm NATO
These are all basically the same, and any gun that has one of these terms stamped on its barrel can happily eat all of them.
There are some differences in bullet weight and cartridge pressure, and this affects the flight performance you'll get out of them, but modern guns are good for any of them.
If you aren't careful, or if you're asking for your 9mm overseas, there's a whole bag of tricks the clerk can dump out on the counter for you.
A request for "9mm" in Europe, for example, could get you a box of 9x18 Makarov, used in the popular Russian gun of the same name.
It looks really similar, but this round is not compatible with your Glock 19, which shoots the slightly longer Parabellum cartridge.
Even better, you can get a .380 auto, which in Europe gets called the "9x17," "9mm Browning" or "9mm short."
Carelessness here could also see you holding a .38 Super (which measures 9x22), or the 9mm Magnum, which probably won't fit in your gun at 9x29, but who knows.
And that's just 9mm, the world's most popular cartridge. Don't even ask about .45 ACP versus .45-70 or .45 Gap, .45 short auto, .45 Colt and so on.
The best way to untangle this mess (which took a solid 150 years to tangle up in the first place) is to just read your gun's manual and buy only the ammo it says you should buy.
2. Should You Go +P? +P+? Magnum?
There's another way your ammo choice can become complicated. Some ammunition is labeled "+P," as in "9mm+P."
Plus-P ammunition is loaded with a little extra powder in the cartridge, and so it generates somewhat higher pressures and pushes the bullet faster.
This kind of ammo was developed during the 1980s as a response to the perceived weaknesses of ordinary 9mm ammunition, which eventually and inevitably led to +P+ ammo, because there’s always somebody who will take things too far.
Magnum ammunition is a similar concept.
By making a .38 Special cartridge extra long and putting some extra powder in it, ammunition manufacturers can pack a much stronger punch into the same bullet.
10mm is considered a magnum round for semi-autos, with the cut-down version of this round being the goofy old .40 S&W round.
It is very important to load your gun only with ammunition that it's rated to handle.
This really isn't a problem for magnum rounds, which are designed to be longer than their weaker counterparts.
A gun that's designed to shoot .38 Special, for example, can't close its cylinder if you load it with .357 Magnum rounds, which stick out from the back of the chambers.
Likewise, .40 S&W magazines are too short to accommodate the longer 10mm round.
This prevents you shooting overpowered ammunition in a gun that's too light to handle the pressure of a high-powered round.
The distinction is a little more subtle with +P ammo.
These rounds have the same dimensions of the older 9mm rounds, so they usually fit in guns from before 1985.
It's pretty important not to shoot 9mm+P from a gun that's not rated for the pressure, however.
Always check the manual to find out what the max limit is on your gun. For the record, there's usually no problem going down a step.
For example, any gun chambered for .357 Magnum can handle .38 Special, no problem, and many 10mm guns can handle the weaker .40 S&W cartridge.
3. Decide What the Ammo Is For
Before you buy ammunition, it helps to decide what you're buying it for. Target rounds are usually a cheap and no-frills way to shoot.
Ball-type ammo is relatively good at penetrating barriers, such as glass, while hollow point bullets are designed to expand inside a target and do maximum damage.
These rounds have different terminal performance when they hit a target.
The ball-type rounds tend to penetrate, while hollow points might get hung up in thick clothing or deflect off of a surface.
Wadcutter rounds are less powerful, but their sharp edges leave neat holes in paper targets.
4. Buy Cheap Defensive Ammo
Each of these rounds also has different ballistic performance in the air.
Because ball-type and hollow point rounds have different weights, different mass distribution and different drag coefficients, they behave differently on their way to the target.
Lightweight wadcutters, for instance, tend to bounce up from a flat trajectory more than the heavier ball ammo.
Copper rounds behave differently from lead, while more exotic stuff behaves all sorts of ways in the air.
Because every ammo type acts differently, it's helpful to occasionally practice with the same ammunition you keep for defensive use.
It would be a real shame to practice for years with wadcutters and ball rounds, even zeroing your sights for that ammo, only to confront a burglar and shoot all your hollow points over his left shoulder because the bullets have a different aim point than you're used to.
You can generally get away with buying loads of cheap defensive ammo and practicing with it.
Because most hollow points and frangible rounds behave in similar ways when they hit, you can probably skip the gimmicky R.I.P. bullets and other exotic stuff for affordable defense rounds you can shoot through by the box.
5. Buy Target Ammo That's the Same Brand as Your Defensive Rounds
Not everybody is a billionaire, so practicing with $1-a-round ammo every time you go to your private indoor range may not be practical for you.
In that case, you can get a second-best experience by practicing with target ammunition that's as similar as possible to your defensive rounds.
To do this right, shop around for a performance round you like.
Once you have the hollow point or soft nose round you're happy with, take a look at the downscale product lines made by that same manufacturer.
Winchester White Box, for example, is a jacketed hollow point that weighs in at 115 grains. Winchester also makes a target round at 124 grains, but at roughly one-third the price.
These rounds get made on the same machines, using the same materials, and so they mostly behave the same in flight.
If you practice with the cheap stuff that's similar to the expensive stuff, then everything from your sights to your grip should perform the way you need them to when it's time to shoot the defensive rounds.