Grains do not Refer to Gunpowder?

By CTD Rob published on in Ammunition

This may seem basic to some of you shooters out there, however the number of calls we get referring to this little misnomer may surprise you. When buying factory ammunition, referring to grains has nothing to do with how much gunpowder the cartridge has. The term grains refers to the projectile’s mass or weight. A grain is a very small unit of measurement where there are 437.5 grains in an ounce. Therefore, if you were to purchase a box of .223 Brown Bear 55 Grain FMJ, the 55 refers to the mass of the bullet itself, not the entire cartridge—just the projectile.

Gunpowder outside a cartridge

Bullet, Powder, and Cartridge

Some of the confusion comes from the manufacturing and loading of cartridges. Many use grains as a unit of measurement when loading propellants in ammunition, so technically, those who say that grains refer to the propellant are partially correct. However, on a box of ammunition intended for purchase, the grains advertised almost always refer to the projectile’s mass. The term grains drew from the approximate unit of mass in one seed of cereal such as wheat or barley. Although no longer recommended, medical practitioners still use grains occasionally as part of the apothecaries’ system, especially in prescriptions for older medicines such as aspirin or Phenobarbital.

So why should you care how many grains your projectile weighs? Bullet weight affects the way it flies and how it performs when it hits its target. A heavier bullet travels slower but hits with more momentum, while a lighter bullet has a flatter trajectory and greater velocity. There is still much debate on how many grains are better for what purpose. For defensive ammunition, some people go with a heavy grain hollow point, while others prefer a lighter, faster bullet. I would encourage you to keep in mind that putting a round on target is far more important than how many grains it carries with it. Unless you are precision target shooting, hunting animals from great distances, or you are a career military or law enforcement sniper, then just go with the manufacturer’s recommended use for the round in question—it usually says it right on the box!

For defensive purposes, my .45 ACP bullet of choice is Speer Gold Dot 230 grain ammunition. I like other brands too, but this has been my choice for years and I trust it as reliable ammunition. Shameless plug aside, I practice and train often with this load, and consequently, I know exactly how it shoots in my gun. Remember that besides using plinking ammunition, try to practice the way you fight. If you spend months becoming a proficient shooter with inexpensive target ammunition, you may find your gun performs differently with self-defense ammunition in play. This is not something you want to learn while trying to defend yourself.

Here is a quick ammunition acronym guide. Most of this information applies to pistol and rifle ammunition, shotgun shells are going to have to wait for another post!

  • FMJ – Stands for full metal jacket, which means the manufacturer encased the projectile in a hard metal exterior. The jacket allows for higher muzzle velocities than bare lead without depositing significant amounts of metal in the inside of the barrel. FMJ bullets do have some disadvantages. Soft tip or hollow point bullets expand upon impact, where FMJ ammunition does not. This lack of expansion causes less damage to soft targets such as animals and people. However, since FMJ bullets tend to penetrate hard targets more efficiently, the FMJ bullet is better suited for military applications, where shooting through armor and barriers is more likely. I should note that some gun ranges do not allow FMJ ammunition, so make sure you ask.
  • FPS – This refers to how many feet per second the bullet travels at its fastest velocity, usually at or near the muzzle. Lighter bullets usually have higher velocities.
  • JHP – Stands for jacketed hollow point. Manufacturers designed hollow points to expand in size once within the target. This maximizes tissue damage, blood loss, and shock. This also allows the bullet to remain inside the target, thereby transferring all of its kinetic energy to that target. Jacketed hollow points or plated hollow points contain a coating of harder metal to increase bullet strength and to prevent fouling the barrel with lead stripped from the bullet.
  • +P+ or +P – Refers to overpressure ammunition. This means that the manufacturer loaded the cartridge with a higher pressure than standard for the caliber. This typically produces rounds with higher muzzle velocities. Because of this, +P ammunition is typically found in handgun calibers which might be used for defensive purposes. Always find out first if your gun can handle a +P cartridge. Some firearms have injured shooters when the chambers failed to handle the blast.

I hope that we cleared up some of the ammo buying jargon you may run into. Buying ammunition can be a little daunting at first. Do your research before you arrive at the checkout counter, but remember that a well placed round, no matter what kind, is the right round for the job. The best-suited cartridge in the world does you no good if you miss your shot.

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The mission of Cheaper Than Dirt!'s blog, "The Shooter's Log," is to provide information-not opinions-to our customers and the shooting community. We want you, our readers, to be able to make informed decisions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (16)

  • John Watson


    Is the powder used in cartridges manufactured in specific shapes to maximize compaction ? Flakes, rounded, or other shapes of individual grains in order to maximize explosive force to deliver the bullet ?


  • Doc_brown


    CTD Rob,

    Thank you for taking the time to write this article. I appreciate accuracy in communication. I love knowing how things work.

    In the spirit of that, I thought I would offer some corrections to your use of the term Mass/Weight and Momentum vs Force..

    In your article you said, “The term grains refers to the projectile’s mass or weight”.

    Technically, weight is the effect of gravity on a mass.

    1) Mass is a measurement of the amount of matter something contains, while Weight is the measurement of the pull of gravity on an object.

    2) Mass is measured by using a balance comparing a known amount of matter to an unknown amount of matter. Weight is measured on a scale.

    3) The Mass of an object doesn’t change when an object’s location changes. Weight, on the other hand does change with location.

    There have been many studies here on earth that show, depending on where you stand on the surface of the earth, that you may weigh a few pounds more or a few pounds less. However, your mass would not have changed. This is caused by fluctuations in the earth’s gravity Cool huh?

    You also mentioned that, “A heavier bullet travels slower but hits with more momentum, while a lighter bullet has a flatter trajectory and greater velocity.”

    Momentum measures the ‘motion content’ of an object, and is based on the product of an object’s mass and velocity. Momentum doubles, for example, when velocity doubles. Similarly, if two objects are moving with the same velocity, one with twice the mass of the other also has twice the momentum.

    Force, on the other hand, is the push or pull that is applied to an object to CHANGE its momentum.

    The collision of one object with momentum into another means that there is an impact force. That is the transfer of energy from one object to another over a period of time.

    This is force.

    So, it the correct term would be “…hits with more force”

    Thanks again for the article!


  • pete J


    I was fascinated with your article. Living in so.Ca. you don’t get much of a chance to shoot, unless you travel at least an hour or more to an out door range. So needless to say, I’m a rookie. Please keep up the simple jargon for us rookies. Thank you.


  • dying breeds


    it is true that 1 grain is equal to 1 1/3 grain of wheat. there are 7000 gr in 1 lb of gun powder.


  • MrsS


    Also a newbie – have 2 Glock 9mm and just gifted myself a Springfield XDS.
    I love learning as much as possible about shooting and gun ownership, in general.
    I like the science behind it all and it’s never a bad thing for a lady to be well informed on the topic :)
    Any suggestions for good discussion boards/sites?


  • phil haurus


    I’m a newbie to all of this. Never thought that guns and ammo was so complicated and
    full of technique and science. I enjoy websites like this and stuff on You Tube like
    hickok45,etc. I learn a lot from viewer comments,too.


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