The world of ammunition is chock-full of questions, myths and misconceptions. Let’s take a closer look at some of the most frequently asked questions about ammo.

Are Full Metal Jacket Bullets Bad for Your Gun?

Actually, full metal jacket bullets can be good for your gun! Let’s dig deeper on this one, as it’s a complex topic with plenty of exceptions.

A jacket around a lead-core bullet allows for higher pressure and temperature while preventing the comparatively soft lead from melting or wearing off inside of the barrel. If lead builds up, accuracy can suffer. Worse yet, pressure can increase to dangerous levels as the “hole size” of the barrel becomes smaller. So, in very general terms, the invention of jacketed bullets allowed ammunition and firearms manufacturers to produce bigger and faster ammo. And there’s less chance of dangerous lead build-up that can cause the self-destruction of your firearm.

A line-up against a white background of four types of bullets both on their own and encased in the appropriate brass casings.

Most modern rifle cartridges use jacketed bullets because the pressure, temperature and velocities are too much for lead bullets to handle without the protective jacket. The lead round shown here is for a .300 Blackout subsonic cartridge which runs at handgun velocities. (Photo by Tom McHale)

On the other hand, and by design, the jacket material is harder than lead. So as it’s forced through the rifling of the barrel, it produces more friction and wear and tear on the steel. For handguns, this isn’t a big deal. Handguns operate at much lower pressures and velocities than rifles, so it takes a long, long time to wear out a handgun barrel. Super-fast and high-pressure rifle barrels may “wear out” after a few thousand shots.

Some handguns, like lower-pressure single-actionA single-action (SA) trigger is the earliest and mechanically simplest of trigger types. Single-action means pulling the trigger does one action: releases the hammer or the striker. revolvers, were designed for lead bullet use. There’s certainly nothing wrong with using lead within its intended pressure and velocity ranges. If you enjoy shooting lead bullets, just be sure that your handgun manufacturer recommends it — and keep that bore clean.

What Improves When a Bullet Spins as It’s Fired?

Good things happen when bullets spin. To understand the classic analogy of why rifles and handguns use internal barrel rifling to impart spin, just envision a football quarterback. We’ll use John Elway, the king of high-velocity bullet passes, as our example. When Elway launched a long bomb, he always spun the ball. In fact, all quarterbacks do. That’s because a spinning object has inherent stability in flight. Physics concepts of gyroscopic stability and inertia encourage spinning objects to maintain their trajectory and orientation. For an object like a football, that means the pointy end remains aimed in the direction of flight. If footballs or bullets don’t maintain orientation (pointy end forward), then they are flying in a sub-optimal way and experiencing more drag and wind resistance. Just as throwing a football end over end will slow it down faster and embarrass you in front of the fans, a bullet tumbling end over end won’t go as fast or as far. And it certainly won’t be as accurate.

What’s the Best Ammo for a 9mm Gun?

This is an easy one, so we can answer it exactly like the questions of what brand of truck is best and whether New York or Chicago pizza is better.

OK, so that was a trick answer. Which ammo is “best” depends on what you want to do with it. For range plinking, the best 9mm ammo is safe but inexpensive. For competition, the best ammo has to meet minimum power factors and be accurate and reliable. Misses and malfunctions cost points and trophies. For self- or home defense, things get complicated.

First and foremost, the “best” 9mm ammo for defensive use will be designed specifically for that purpose. Especially with the small and fast 9mm, round-nose or full metal jacket ammo tends to penetrate and make small holes. While that can certainly be lethal, that result isn’t desirable because lethality isn’t the goal. Stopping an attack as quickly as possible is. If you can do that without causing the death of your attacker, all the better. Most defensive 9mm ammo is designed to quickly stop an aggressor by expanding and slowing when it hits an organic target. That causes more fight-stopping damage more quickly than a smooth bullet passing through cleanly. Now let’s get to how to find the “best” defensive ammo.

The FBI and other law enforcement agencies spend millions testing ammunition to ensure that their officers are equipped with the most effective fight-stopping bullets possible. These tests evaluate three major performance metrics. How much will the bullet penetrate an organic target? They look for 12 to 18 inches before the bullet stops forward motion. While that sounds like a lot, it’s not when you consider angles and the possibility of shots passing through extremities first. Second, they look for expansion performance of the bullet to determine how large a wound channel it creates. Last, both of these metrics are tested in scenarios where the bullet first passes through barriers such as clothing, wood, drywall, automotive glass and light steel.

Four mushroomed bullets showing their lead cores and blue polymer filling, next to a black box of Federal Guard Dog .45 ACP self-defense ammunition

Not all expanding bullets are hollow-point designs. This Federal Guard Dog uses jacketed bullets designed to expand on impact. (Photo by Tom McHale)

Your challenge is to find ammo that meets these criteria when fired from your gun. If you shoot a subcompact pistol with a short barrel, the velocity will be less than when the same ammo is fired from a full-sized handgun. So you may need to consider special short-barrel loads offered by many manufacturers. You may also want to consider the weight of the projectile. For example, 9mm ammo is most commonly found in 115-, 124- and 147-grain bullet weights. Those heavier bullets might be great for a longer-barreled pistol, but they might not perform from a compact.

Are Hollow-Point Bullets More Deadly?

The significant word in this question is “deadly.” If we are limiting our discussion to the realm of concealed carry and self-defense, deadly isn’t an objective. Stopping someone from doing whatever they’re doing as quickly as possible is the goal. They key word in that statement is “quickly.” Even a small bullet such as a .22 LR projectile can be lethal. However, if it takes minutes to stop a determined attacker, that’s not helping you much. A more effective caliber and bullet that stops an attacker quickly, whether or not it’s “lethal,” may be a better option.

Three SIG-Sauer VCrown JHP cartridges featuring nickel-plated casings and brass-jacketed bullets. Two are 9mm and one is .45 ACP. The rounds stand in front of their respective retail boxes.

Nearly every law enforcement agency in the country uses hollow-point ammunition, not only for effectiveness on target but also for the safety of officers and bystanders. (Photo by Tom McHale)

Hollow-point bullets aren’t designed to “kill” more effectively. They are designed to incapacitate more quickly. That’s an important distinction. The expanding effect of a hollow-point causes more damage with each shot, all else being equal. So, at least in theory, a hollow-point may stop an aggressor faster and with fewer shots. As the theory goes, fewer shots mean less chance of lethal damage in multiple areas of the body and non-survivable levels of blood loss from multiple holes.

There’s another factor to consider. Hollow-point bullets, because of rapid expansion and increased drag, are less likely to completely penetrate an attacker and continue on their way, potentially causing injury to others. While case statistics are few, it is clear that hollow-points are less likely to exit the body.

Those are some of the reasons that nearly every law enforcement organization in the country uses hollow-point bullets in service pistols.

What Are Dum-Dum Rounds?

Two fully mushroomed DT Defense bullets sitting atop a retail box of cartridges

One of the reasons that the Dum Dum Arsenal manufactured soft- and hollow-point bullets was to create larger holes in targets and stop those targets more effectively. (Photo by Tom McHale)

The term “Dum-Dum bullet” is slang that refers to a hollow- or soft-point bullet designed to mushroom on impact. Simply put, it’s another way of describing any hollow-point expanding bullet.

The term “Dum Dum” comes from its place of origin, the Dum-Dum Ammunition Factory near the West Bengal town of Dum Dum, India. Back in the mid-1890s, Captain Neville Bertie-Clay, Superintendent of the Dum Dum Arsenal, developed a .303 cartridge designed to more effectively stop a “determined rush” of attackers in close-quarters fighting. At the time, soldiers complained of existing bullets causing small wounds that would not stop the enemy quickly enough. While not the first expanding bullet, the term stuck as the definitive slang description of hollow-point ammunition.