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I think the next several columns are going to be about ammunition. If you want to dumb it down, there are three basic types of ammo: Handgun, rifle and shotgun.

But that’s really simplistic, because there are rifles that are chambered for handgun ammo, and handguns chambered in handgun, rifle and shotgun calibers. Shotguns are really the only standout. Shotguns shoot shotgun shells.

Today, we’re discussing handgun ammunition. Handguns are all the rage right now, so I wanted to cover that first. First, you have two types of handgun ammunition, centerfire and rimfire.

Centerfire calibers utilize a primer in the center of the bottom of the cartridge. Hence, centerfire. The hammer or striker from the pistol will hit the primer, the primer will create an internal spark and ignite the gunpowder, and the expansion of that gunpowder igniting will push the bullet down the barrel. Most handguns are chambered in centerfire calibers. These are reloadable calibers and range from .25 ACP to .500 Magnum.

Rimfire are normally smaller calibers like .17 HMR and various .22s (SR, LR, WMR). These calibers are also commonly used in rifles. Rimfire cartridges don’t have that central primer like centerfire. Instead, they have an internal primer built into the rim of cartridge that the hammer, striker or firing pin hits to set off the round. Rimfires can not be reloaded.

The other downside to rimfires are they shouldn’t be dry-fired, which is pulling the trigger on an empty chamber. This is normally done for training purposes on a cleared weapon. Doing this on a rimfire can peen the end of your firing pin, striker or hammer, or peen the edge of the chamber. This can damage the weapon — sometimes catastrophically.

There are several ways ammo can be measured. First is caliber, which is the diameter of the bullet. The caliber of your pistol should be clearly marked on the firearm itself (on any modern gun, anyway).

Some calibers are decimal and some are metric. For example, .22, .380, .32 and .45 are all decimal measurements. That means the bullet itself is .380 of an inch or .45 of an inch in diameter. Some will be metric measurements — 9mm, 10mm, 5.56mm. This is the diameter of the bullet itself in millimeters. Yes, 5.56mm is usually a rifle round, but there are pistols chambered in that caliber.

Next is grains. When you purchase 9mm ammunition, you will see 9mm followed by a grain measurement of the bullet: 9mm 115gr. That is a 9mm round that weighs 115 grains. That is the actual mass of the bullet. If you like math, there are 437.5 grains in an ounce (or 15.43 grains in a gram). You will see both decimal and metric bullets measured in grains.

This distinction is important because most ammunition is available in several different weights. Common 9mm ammo can range from 115 grain to 147 grain, and you can find lighter or heavier if you look around. Each grain weight will perform differently in accuracy and cycling. And a lot of handguns won’t even feed 147-grain rounds.

Usually the next thing is an abbreviation for the type of bullet: 9mm 115gr FMJ, or 9mm 115gr HP. That is the design of the actual bullet. FMJ stands for full metal jacket. That means that the lead bullet has a complete metal (usually brass) coating around the lead. HP stands for hollow point, which means that the bullet will have a hole in the middle of the round, but it won’t go all the way through the bullet. If they did that, the powder would fall out.

FMJ bullets are designed for target shooting and are cheaper than HPs. Now the military has been killing people with FMJs for decades, but in today’s self defense scenarios, FMJs come with a few downsides. FMJs can over-penetrate your target. That leaves people behind your target at risk. FMJs don’t expand as well as HPs, so a 9mm round will leave a 9mm hole through your target. If you miss vital organs, you’re probably not stopping your threat.

HP rounds are designed for self-defense. These rounds will expand on hitting a “wet” target — sometimes to almost twice their size. That does several things. First it helps stop over-penetration, so others aren’t put at risk. Second, it makes a larger hole, so if you miss vital organs by a slight amount, the round becoming larger can make up for that little bit. Third, it can cause hydrostatic shock.

Human bodies are about 60 percent water, so we are a “wet” target. That means that usually all energy that round is carrying will be transferred to the target, which can disrupt and injure the nervous system and organs. In other words, HPs pack a lot more punch than FMJs. But they don’t make up for shot placement.

Next week, part two of handgun ammo.

Capt. Cayle Wills is a salesman and gunsmith at Higher Power Outfitters (1826 Tamiami Trail, Punta Gorda). Contact him at 941-916-4538 or

Capt. Cayle Wills is a salesman and gunsmith at Higher Power Outfitters (1826 Tamiami Trail, Punta Gorda). Contact him at 941-916-4538 or


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