Bullet Grain: What It Means and Why It’s Important

If you’re a new gun owner, you probably don’t really know what bullet grain means. You may look at a box of ammo, see “115-grain” written on the side, shrug, and flip it over to look at what you really care about: the price tag. Before you do that, take some advice from a few seasoned firearm aficionados and consider the grain for the ammunition you’re purchasing.

Why think about bullet grain, you may ask? Well, actually, the size, shape, and material your ammo is made out of affects factors such as accuracy, recoil, and terminal ballistics. Let’s check out what bullet grain really means and how it can make you a better overall marksman.

Editor’s note: this is an article for a new gun owner to explain the basic concepts of bullet grain and how weight may or may not impact the shooting experience. It does not imply there is a direct relationship between bullet grain and a shooter’s ability.

What Does ‘Bullet Grain’ Mean?

A grain (“gr” for short) is a basic unit of weight measurement. One grain is equal to 1/7,000 of a pound or 1/437.5 of an ounce. If you’re like me and have a hard time imagining realistically how much things weigh, here are some common household items I use as a guide to put things in perspective:

• A new dime weighs about 34.5 grains
• A dollar bill weighs about 15.4 grains
• A sheet of printer paper weighs about 77 grains
• A “AA” battery weighs roughly 385 grains

All bullets are classified based on their weight in grains. For example, the most common 9mm Luger cartridges have bullet weights of 115 grains, 124 grains, or 147 grains.

The range of bullet weights is actually much wider than what you might think, with the lightest being 17 grains such as in a .17 HMR round and the heaviest being upward of 700 grains such as the .50 BMG cartridges. Most rounds have a shorter standard range than that, though. One example is the classic AR-15 .223 cartridge, which ranges from 40–77+ grains with the standard being 55 grains. If you’re more of a 9mm Luger type, those usually come in options ranging between 60–160 grains.

A common misconception when it comes to the term “grain” is that the number on the ammo box is a reference to the amount of gunpowder in the cartridge (which, to be fair, gunpowder is also measured in grains if you’re into handloading). The label, however, is strictly speaking about the weight of the bullet (projectile that exits the barrel). Now that we’ve covered the basics of what “grain” refers to, let’s take a look at how you can use that knowledge to improve your shooting.

Advantages of a Lighter Bullet

There are so many great options out there for ammunition. When choosing which type of cartridge to use, you’ll want to consider several factors such as the type of shooting you’ll be doing (hunting, plinking, self-defense, etc.) and which rounds feed better through your firearm. We’ll take those factors into account when comparing lighter-weight bullets to heavier weights, and also discuss how the grain of the bullet affects accuracy, recoil, and terminal ballistics.

Accuracy

With a lighter bullet, you generate more overall speed, which means a flatter trajectory. This makes lighter rounds excellent for long-distance shooting. The lower-grain cartridges are also great for hunting if you plan on making longer shots at smaller game animals such as coyotes or prairie dogs.

One thing to watch out for, though, is wind. Because of the lighter weight, these bullets can be blown off course more easily.

Recoil

You may equate lighter bullets to lighter recoil, which may or may not be true based on the type of recoil management your gun has. Theoretically, though, a lighter bullet should have more recoil because of Newton’s “equal, but opposite reaction” theory. We already talked about lighter rounds having more energy and that energy must go somewhere…

So, instead of arguing the differences in recoil between light and heavy bullets, let’s leave it at this: firing lighter bullets usually feels “snappier,” while firing heavy bullets feels more like a “roll” or “pull.”

Terminal Ballistics

Though you’ll get more speed with a lighter bullet, you do give up a certain amount of energy when talking terminal ballistics (aka how the bullet strikes the target). Less mass means your shot generally won’t carry as far into the target as a heavier round would, so you’ll want to be shooting at non-living targets or smaller game animals in order to keep things more humane.

To recap, lighter grain bullets will give you the advantage of speed and distance, making them perfect for competition or long-range shooting, but have snappier recoil and less penetrating energy when they hit the target.

Advantages of a Heavier Bullet

When you get into the higher-grain cartridges, you gain a lot in terms of effectiveness. Here’s how our heavier contenders stack up in terms of accuracy, recoil, and terminal ballistics.

Accuracy

A heavier bullet is not going to go as far. So, if you take a 400-grain Buffalo Bore Dangerous Game round and try to hit a pig that’s 300 yards away, you’re probably going to miss what you were aiming at. But, on the flip side, the extra weight gives the bullet more stabilization against wind gusts. So, if you get within 100 yards of the pig, you’ll probably have a nice trophy to mount.

Realistically, if you’re just taking your firearm out to the range for some fun plinking, bullet weight won’t matter much. It will really just depend on what you can afford, and what your weapon likes best.

Recoil

Since recoil is calculated based on several factors including bullet weight, velocity, type of propellant, and design of the weapon, the bullet grain you choose will affect how much your shots will kick. How the shooter feels the recoil, though, is totally subjective, so even though a heavier round may technically generate recoil, it’s still a matter of how you personally perceive the blast.

One thing about heavier rounds that definitely reduces heavier recoil, is using subsonic rounds with a good suppressor. Subsonics are basically all heavier in weight and, with the aid of a suppressor, generate a small enough amount of energy to be absorbed very effectively.

Terminal Ballistics

Here’s where the heavier rounds really shine. If you want effectiveness for defensive situations, larger game, or combat, then higher-grain cartridges will get the job done. The heavier the bullet, the better expansion and penetration you’ll get on impact. This means quicker and more humane kills.

Conclusion: Bullet Grain

Many law-enforcement agencies are starting to choose rounds on the heavier side. The FBI, who landed on the Hornady Critical Duty 175-grain .40 S&W as its go-to. So, as you begin to think about how your choice in bullet weight will affect your shooting, keep these things in mind:

• Lighter weight generally means more speed and distance, but also more recoil and less power at the target. Lighter bullets are good for competition and long-range shooting.
• Heavier weight generally means more effectiveness, making them excellent for defense, large game, and combat.

No matter what ammo you choose, remember to experiment a bit to see what weights work best in your gun and don’t forget to have fun as you get to shooting.

What are your preferred bullet grain weights for different applications? Let us know in the Comment section.

Editor’s note: This post was originally published in August of 2020. It has been completely revamped and updated for accuracy and clarity.