What Does Grain Mean In Ammo?

a man reloads a gun at a shooting range with targets in the background to illustrate How To Dispose Of Ammunition

It’s not unusual to have questions when purchasing a firearm. In fact, when discussing firearms and ammunition at a gun store prior to a purchase, it’s a good idea to ask a lot of questions. This is especially true when you’re unfamiliar with a particular firearm or type of ammunition.

One question that we sometimes get at Sporting Systems is, “What does grain mean in ammo?” This is a good question that we hear not just from first-time buyers but from more experienced firearm owners, too.

Grain is simply a measure of weight. Specifically, grain is the term used for the weight of ammunition, propellants, and archery arrows.

Grain as Measurement: A Brief History

A gain is a unit of weight equal to 0.0648 grams (or 0.002286 ounces). That is about 1/7000th of a pound. It’s one of the smallest units used for measuring weight. In fact, it takes 437.5 grains to equal just 1 ounce.

A single grain is very light. This makes sense as a measure of ammunition since ammo is made up of finely produced and very small pieces.

Merriam-Webster tells us that a grain is “a unit of weight based on the weight of a grain of wheat taken as an average of the weight of grains from the middle of the ear.” Other sources reveal a similar definition, with the consensus being that grain refers to the weight of a single seed of cereal grain.

Based on those definitions, you probably won’t be surprised to learn that a grain is an ancient method of determining weight. As far back as the 8th century BCE, Mediterranean traders were weighing products using grains as their basic measurement.

Two-plus millennia later, the English were codifying grain as measurement:

“Per Ordinance of the whole realm of England the measure of the King is composed namely of a penny, which is called a sterling, round & without clipping, weighs thirty-two grains of wheat in the middle of the Ear.” 

What Grain Means In Ammunition

Fast forward another 800 years or so. Let’s say you’re visiting with us at Sporting Systems, wondering what grain means in ammo.

The answer: Grain is used as a measurement for bullets — more specifically, it’s the weight of the projectile — the portion that leaves the barrel when fired. A box of ammo will list the grain; sometimes it will abbreviate it as gr. or grs.

You might hear a member of the Sporting Systems staff refer to a “Minuteman 45-70 405 grain hard cast ammunition.” Or you might hear about “Blue Bullets polymer coated projectiles, 125 and 147 grains, and the round nose style.”

However, the truth is that for most casual firearms purchasers, the specifics of the bullet grain are less important than other considerations, such as the specific terminal ballistics (i.e., behavior) of a certain grain in a certain gun.

For instance, you might ask if you need a smaller bullet, a lighter bullet, a smaller grain bullet, or a higher grain bullet. Some heavy bullets produce more recoil. Others travel longer distances.  

In other words, you can use these broad terms (light bullets, heavier bullets, etc.) to find what you need. It is, however, important to know if your firearm needs a specific grain (115 grains — or 115 gr. — 124 grains, etc.) or range of grain weights in order to function properly.

As we stated at the outset of this piece, it’s important to ask questions if you’re unfamiliar with any of the details that go into the purchase of a firearm. Grain and ammunition measured in grains are just two of those details.

Sporting Systems

An experienced firearms seller such as those you’ll find at Sporting Systems will help you decide what’s best for you and your particular firearm needs.

For example, when it comes to ease of handling, accuracy, and other details of shooting a firearm, it may very well be that a certain firearm performs better for you with a specific projectile weight.

It can often take some experimenting at a shooting range to learn what type of firearm and what bullet weight works best for you.

If you still have questions, please don’t hesitate to reach out to us at Sporting Systems. We are here to help, and we look forward to speaking with you.


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