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Does Bullet Grain Matter?

Does Bullet Grain Matter?

March 20, 2019

When it comes to buying ammo, most shooters are content to pick up the first box they see that has the same caliber as their rifle printed on the box. But after that .223 or .308, or even .577 Nitro Express title, you might notice a little number next to it with “GR” at the end. This mark denotes the grain or weight of the bullet itself.

For most, the weight of an individual bullet doesn’t make to much of a difference to them at the range. But once you’ve added all of the parts and accessories you can to your AR, and you’re looking to scratch that perfectionist itch in a new way, it’s time start taking a look at your bullet grains. But does it really matter? Let’s explore what grain weight is and how it could affect your shooting.

Bullet Grain Basics

First things first, grains do not refer to the amount of powder in your cartridges.

Grains are a unit of measurement for mass. The actual weight of a grain is extremely small. To weigh an ounce, you’ll need 437.5 grains. To give another example, a paper clip weighs about one gram, and 15.43 grains weigh as much as a single gram.

Essentially, the grain count of a round is a way to measure the size of the bullet. So when the box of 5.56 ammo you just bought says that it’s 62 grain, that means the bullet weighs that much.

Selecting the Right Grain For Your Use

Like most things in life, there’s no “one size fits all” grain for your shooting applications. While you’re limited to a certain range of calibers for your particular AR, there are a variety of grain weights you can choose from within that caliber. It’s important to familiarize yourself with the characteristics of each grain weight before you start buying spam cans full of ammo.

Perhaps the easiest metric you can use to figure out which grain weight is right for you and your rifle is to think about how you use your AR and what kind of shooting you do.

Range Day Use

If you’re interested in putting lots of rounds down range and shredding paper targets, really whatever ammo is cheapest will do fine. For most casual shooters, grain weight makes less of a difference than cost does. Just make sure you’re buying ammo that cycles well through your AR and doesn’t break any range rules, like steel core restrictions.

Self Defense

If you’ve outfitted your AR as a self-defense weapon, you’re likely interested in rounds that align with that purpose. For self-defense purposes, you want a bullet that will penetrate a soft target and expand or tumble, while still staying in the body to prevent collateral damage.

Generally, it’s recommended that a larger grain and heavier bullet is more suited for self-defense. However, others recommend the use of jacketed hollow point rounds over heavier weight rounds.


Not unlike self-defense, grain weight is less important than penetration and expansion. You want a bullet that will quickly and humanely put down your target. Rather than grain weight, you’ll want to consider what kind of animal you’re hunting. There are also some legal considerations to keep in mind, as some states require certain calibers to be used when hunting specific animals. Additionally, there are specialty rounds that are available for certain game. These tailored rounds should be your first choice.

Precision Target Shooting

In many cases, those who are shooting long range or at precision target shooting competitions will rely on match grade ammo. In these cases, accuracy is prioritized over all other factors.

For targeting shooting, there are some general rules of thumb when it comes to grain weight and accuracy. In general, heavier bullets are less likely to be affected by the wind, meaning they will fly true downrange. However, if the round is too heavy, it might not have the velocity to maintain stable flight to the target.

The performance of your target rifle is affected by a combination of the grain weight of the round, the length and twist rate of your barrel, and many more factors. The best way to figure out which grain weight is right for your precision shooting needs is to try a variety of weights at the range until your achieving your desired results.

How Grain Affects Recoil

Of course, most shooters are concerned about how a given round will affect their perceived recoil. This is fair, as recoil can impact your ability to make rapid follow up shots, and if nothing else, more recoil means sore shoulders at the end of the day.

Bullets with different grain weights might feel different as you shoot them. Typically, those who shoot lighter weight bullet find that the recoil feels snappier. Conversely, heavier rounds have a sort of pushing recoil. Some feel that heavier bullets have less felt recoil, but not much.

If you’re looking to make minor changes in the performance of your AR and handles recoil, it’s always a good idea to start by changing the grain weight of your rounds before you start changing the setup of the rifle.

The Performance of Your AR

Just like some people prefer some foods to others, your AR might prefer some grain weights to others. It can be a minute difference, but you might notice a difference in the elevation of your groupings, or you might find that your rifle cycles more efficiently with some grain weights than others.

There’s no objective way to match grain to gun, so the best way to figure out the right combination is to simply hit the range with a variety of ammo in different grain weights. This allows you to dial in your rifle and ammo set up to ensure optimal accuracy and performance for your needs.

So Does Bullet Grain Really Matter?

Well, if you’ve read all of the above, you’ll know that the answer is a resounding “it depends.” How you use your rifle and what kind of performance you expect influences how much importance you place on grain weight. If nothing else, it’s important to try a variety of ammo grain weights with your particular AR rifle.

Customize Your AR

If you’ve found the right barrel, grain weight, and handguard for your AR but still feel like it’s missing “something,” it’s likely that you need new rail covers and iron sights. RailScales offers premium rail covers made from materials like G10, aluminum, and High-Temp Polymer. We also offer precision iron sights that are meant to mount seamlessly on your laser modules.

Order your RailScales AR accessories today.