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What does the Grain of a Bullet Mean?

02.12.2022

What does the Grain of a Bullet Mean? 

If you’re new to guns, you’ve likely noticed a reference to grains on the side of your ammo box, but you may not know what that means. If the box featured an abbreviation like “gr” or “gn” after a number, you may not have even known that it was a reference to grains. Or, you may have thought that grain weight represented the powder weight, or the overall power of your gun cartridge.

Grain is important though and you shouldn’t just buy any ammunition without consideration for grain. It impacts the recoil, accuracy, and terminal ballistics of the round.

So, to help you figure out what grain you should be looking for (and what grain is in the first place), we’re telling you everything you need to know about grain.

A grain is a measurement of mass that dates back to ancient times. Originally, one grain was supposed to reflect the weight of a single seed of a cereal grain, like barley or wheat. Obviously, since seeds vary in weight, it wasn’t exactly a standardized unit.

These days, a grain (abbreviated gr) is standardized as 1/7000 of a pound or 64.79891 mg. That’s obviously a teeny tiny unit of measurement, so let’s look at the weight of some common items measured in grains to give you some context:

  • A paperclip weighs about 15.4 gr
  • A US nickel weighs about 77.2 gr
  • A thumbtack weighs about 123.5 gr
  • A tablespoon of butter weighs about 154.3 gr

Grains are basically only still used to describe the weight of bullets and the amount of propellent used in a round, but unless you’re handloading, you probably won’t encounter the latter use much either. When you look at an ammo box and it lists grain, it’s describing the bullet weight, which is known as grain weight.

Bullet Grain Effects on Accuracy, Recoil, and Terminal Ballistics

Accuracy

All other factors being equal, a lighter bullet can reach higher speeds than a heavier bullet. Higher speed means a flatter trajectory, so lighter bullets are great for long distance shots, whether at the range or on a hunt. The flip side is that lighter bullets are more impacted by the wind, which can blow the round’s flight path off.

Heavier bullets won’t go as far, but that can be offset by adding more gunpowder to the cartridge. At the same time, the heavier weight helps prevent higher grain bullets from being as impacted by wind.

Still, you’re generally better off reserving heavy bullets for short ranges and investing in a windage-adjustable optic to pair with a lighter bullet for long-range shooting.

Recoil

The effects of bullet weight on recoil aren’t always simple, but different weights are certainly something to be taken into consideration. Physics means that a heavier bullet, when compared with a lighter bullet, is going to require more force to get going to a certain speed.

Because every action has an equal and opposite reaction, that means that pound for pound, a heavier bullet is going to generate more recoil in the same gun firing a lighter bullet. Theoretically, a lighter bullet with the same powder charge will go faster, and recoil less.

Again, that’s just in theory. In practice, there are a ton of other factors that impact the amount of recoil that you experience.

The type of gun, size of the gun, gunpowder charge, and recoil management system that your firearm uses all make a massive difference in the amount of felt recoil, so the grain of a bullet isn’t a great indicator of recoil.

When it comes to ammo, the best way to minimize recoil is to just go with a subsonic ammo. These rounds create less energy than standard ones, so they have less recoil, especially when paired with a good suppressor.

That said, lighter bullets are also a good way to lower recoil if you’re shooting something like a paper target where impact force/penetration isn’t an issue, and you want lower recoil for rapid follow-up shots.

Terminal Ballistics 

Terminal ballistics refers to the behavior of a bullet when it hits the target.

Despite the greater speed, the small mass means that a lighter bullet will have less energy when it hits the target. This means the smaller round won’t penetrate as deeply, whereas with a heavier bullet you get deeper penetration. Lighter bullets also don’t expand as much.

For target practice, that’s fine, and it’s usually not a problem with small game either. In fact, less energy and less penetration can even be better for small game since the round can kill without creating too much damage.

When it comes to self-defense or hunting medium to large game, smaller bullets can be a problem due to their lighter projectile that is not generally powerful enough to do the job. In this case, you’ll want to go with a larger round that has higher pressure.

Heavier Bullet or Lighter Bullet – Which is Better?

For Self-Defense:

When shooting for self-defense, you want a lot of stopping power and generally only need to shoot a short range. You also want to avoid overpenetration, which can be extremely dangerous in terms of the potential collateral damage that could be inflicted upon anyone and anything that happens to be behind your target.

That means a mid-range to heavy bullet is perfect for defensive purposes. This is why most handgun ammo you see marketed for self-defense tends to be on the heavier side of what is normally available for a given caliber.

For Range Training:

For training, you’ll want to go with a bullet that has a similar weight to whatever you’re using in the field. That ensures that shooting feels the same during training as it does in the field, helping you build important muscle memory for follow up shots.

Man Firing Pistol at Target in Shooting Range

If you’re shooting recreationally, however, you can shoot pretty much anything you want. Remember, though, that different bullet weights have different implications for different shooting distances.

When shooting longer distances, you’ll get less bullet drop (but more windage effects) with a lightweight bullet, so that’s probably the route you want to take. For shorter distances, it doesn’t make a huge difference, so you can shoot whatever you’re comfortable with.

For Competition: 

Generally, competition shooters opt for a heavier bullet because they’re less impacted by wind and have a superior ballistic coefficient. In addition, in competition types where you need to knock over a target, like Steel Target, heavier bullets are less likely to hit the target without actually knocking it over.

It does, however, depend on the type and class of competition that you’re participating in.

Pistol caliber carbine competitors, for example, tend to prefer lighter bullets. This is because these guns have longer barrels and a carbine gas system, which allows PCCs to shoot lighter rounds more reliably.

If you’re not sure what to shoot for the type of competition you’re interested in, visit a competition and ask around. Most competitors are happy to discuss their setup with newcomers and veterans alike.

In general, the things you need to think about are what kind of impact (literally) you need on the target. If you’re just punching holes in paper, a smaller, lighter bullet going faster might be just the thing you need for longer ranges.

For something like steel series, heavier rounds might be preferred. The other thing to consider is of course recoil. A heavier bullet will have more recoil, which is especially noticeable with a pistol. This is why lighter bullets are preferred over higher grain bullets for many sports, like USPSA.

For something like PRS, opinions differ and there’s two ways to go. A heavier, higher-BC bullet can be better at dealing with the wind, and is generally preferred, but a lighter, faster bullet will also experience less drift and drop in some cases.

At the end of the day, finding the right balance between velocity and ballistic coefficient is something that competitors put a lot of thought and experimentation into, and is a big part of why most serious competitors’ hand-load their own rounds to their own preferences.

For Hunting: 

When hunting, preserving meat while also making an ethical kill is generally the top priority (with pest control being a notable exception).

That means penetration is essential, but you do also want some controlled expansion to ensure that the hit actually kills the game instead of just wounding it. Not only is needless pain unethical, but it can also put you in a sticky situation if you’re hunting dangerous game.

a hunter with gun up silhouetted in a a colorful sunrise

That means look for a round that’s heavy enough to do the job while still reaching the distance you need. When indoubt, go with a larger, more powerful round. It’s better to waste a bit of extra meat than to muck around with an animal’s life (or your own).

Larger, heavier, higher grain bullets carry more kinetic energy as they penetrate, making expansion more likely in the case of expanding rounds.This also means that solid hard cast rounds are more likely to get where they need to go if you’re dealing with dangerous game.

This is why for bear and safari game you typically see recommendations for larger, heavier bullets. This is lessof an issue with thin-skinned medium game such as whitetail deer, however, so don’t worry too terribly much about it.

Grizzly Cartridge: Your Home for Ammo of all Grains

No matter the grain you’re looking for, Grizzly Cartridges has the solution! We offer ammo with grains of all sizes, from smaller grains, like our 357 Sig 90gr JHP, and also larger grains like our 500 Nitro Express 570gr SOLID, to everything in between. You can feel confident purchasing ammo of any grain from us, as we hold our products to the highest, most stringent standard imaginable.