What Does Grain Mean When It Comes to Ammo?

Having trouble figuring out what grain means when it comes to ammo? A grain is a unit of weight and is typically used to reference how much a bullet or powder charge weighs. If an ammunition description lists a 200-grain bullet, it’s referencing the bullet’s weight. Just the same, if load data for a cartridge specifies 45 grains of gunpowder, it does not mean you count out 45 little grains of powder, it means you weigh the powder charge until it equals 45 grains. Technically, a single grain—in weight not of gun powder—equals 0.065 grams or 1/7000 of a pound. Arrows and broadheads are also most often weighed by grain.

The more common measurement for small quantities is an ounce and bullets and powder charges could be weighed by the ounce, but the numbers become tedious. For example, since 437.5 grains equals one ounce, a 200-grain bullet would weigh 0.4571429 ounces. Similarly, a 45-grain powder charge would be listed as 0.1028 ounces. (It’s easier for most of us to work with numbers on the left side of the decimal point so weight by grain makes more sense.) Some European ammunition manufacturers do list bullet weights in grams. For example, Norma lists a 180-grain load for the 308 Winchester at 11.7 grams.

What Does Grain Mean in Ammo: Table of Contents

Shotguns and Drams

Muzzleloaders and Olden Days

Which Grain Weight for Ammo is Best?

Other Considerations

Shotguns and Drams

The payload of shotgun shells is weighed in ounces for the same reason rifle bullets are weighed in grains—to eliminate working with tedious numbers. For example, a 20-gauge shotshell might have a payload weighing 1 5/8 ounces, which would equal 710.9375 grains. The same goes for rifled slugs. However, you might see a dram listing on some shotshells—it’s actually a dram equivalent (DR. EQ.)—and it relates to the powder charge. It’s a throwback to the olden days when shotguns were loaded with black powder.

This game load for the 16-gauge shotgun contains 1 ounce of shot, with no mention of grains. It is also a 2 ½ DR.EQ. load.
Richard Mann

Mostly the DR.EQ. references how powerful the shell is, but it has nothing to do with how much shot it contains or how much the shot weighs. For example, a 20-gauge shell with a 1 5/8 ounce payload and a DR.EQ. of 2.5 would hit and recoil harder than the same load with a DR.EQ. of 2.0.

Muzzleloaders and Olden Days

Speaking of the olden days, and according to the book, “The Kentucky Rifle,” written in 1924 by Captain John G.W. Dillin, lead round balls for muzzleloading rifles were often referenced by how many of them it would take to make a pound. For example, a .50-caliber muzzleloader would fire a round lead ball of about 0.490 to 0.495 inches in diameter, and it would take about 38 of these to weigh a pound. It was common to reference the size bullet—lead round ball—a muzzleloader fired by “bore” instead of caliber and grain, because back then everyone knew that a 38-bore muzzleloader fired a lead round ball that weighed 1/38th of a pound or about 181 grains. It should be obvious why this method of weighing bullets went out of fashion.

Round balls are not sold by grain weight because all lead round balls of the same caliber weigh the same. This 0.440-caliber lead round ball weighs 127-grains, which is the same as the bullet used in this 6.5 Creedmoor load. Richard Mann

Which Grain Weight for Ammo is Best?

Getting back to what grains mean as they relate to modern ammunition. You might want to know what’s the best bullet grain weight to use in your gun. There’s no single correct answer because the application you’re using your gun for should determine bullet weight. For example, with the 243 Winchester, you can find factory ammo loaded with bullets from as light as 40 grains to as heavy as 100. Lighter-weight bullets are most often used for varmints, while heavier-weight bullets are most often used for big game. Lightweight bullets can be pushed faster, and heavier bullets can hit harder and recoil with more force.

However, with the modern advancements we’ve had in bullet design, more hunters are turning away from their preference for heavier bullets. This is because bullets are now being built to retain most of their weight after impact, and the mid-weight bullets tend to shoot flatter and hit harder than heavier bullets because they start out at higher velocities. This is not only true with hunting rifles, but it’s also the case with self-defense handgun ammunition. Typically, you’ll find the best balance of external and terminal ballistics with mid-range bullet weights for the cartridge you’re shooting.

All four of these 0.308-caliber bullets weigh 150 grains. But they will all deliver different external and terminal ballistics based on their shape and construction. Richard Mann

What Does Grain Mean in Ammo: Other Considerations

The grain weight of a bullet combined with its construction and what it’s made of is also a consideration. Since copper weighs less than lead, an all-cooper bullet of the same weight as a lead core bullet might be longer and give the appearance it’s heavier. Also, because all-copper bullets tend to retain their weight better than lead core bullets after impact, when using all-cooper/mono-metal bullets, it’s common to use a lighter bullet to achieve more velocity.

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It gets even more complicated when you start considering bullets with a high ballistic coefficient. These bullets are often heavy for their caliber because they’re so long and slender. However, because of their high ballistic coefficient, at extended range, these bullets can outperform the faster moving lighter-weight bullets. Then there are bonded bullets that might look and weigh the same as a standard bullet, but since their lead core is bonded to their jacket, they retain their weight better after impact.

The bottom line is that the grain weight of a bullet only really tells you how much the bullet weighs. By itself, bullet weight is not a reliable indication of how well that bullet might perform after hitting an animal, or about how flat it will shoot and resist the wind. Grains are important, but they’re all about weight and nothing more.

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