I know, I know… who cares about bullet weight? Most people could casually enjoy shooting for years without paying any attention to that little number with the “GR” after it on the boxes of ammo they buy. But you wouldn’t be reading this if you were content with being a mere “casual shooter”, would you?

It’s true that much of the time, bullet weight matters very little as long as you’re using the right caliber. On the other hand, in order to get the most out of your firearm for almost any application outside of casual plinking, bullet weight becomes an important variable that can have a major impact on factors like ballistics, accuracy, and recoil. So how do you know which bullet weight is right for what you want to do? There’s usually no easy answer to that question, but if the issue of bullet weights is a complete mystery to you, here are a few basics to get you pointed in the right direction.

What’s a Grain?

Bullets are measured in a unit of mass called grains (abbreviated “gr.”). One pound is equal to 7000 grains, and there are 437.5 grains in an ounce. Bullets can weigh anywhere between 15 grains for the lightest 17 HMR bullets all the way up to 750 grains for the heavier .50 BMG rifle loads.

.308 Win cartridges
From left to right, the bullets in these .308 Winchester cartridges are 147 gr., 147 gr., 168 gr., 175 gr. Can you tell their weight just by looking? Yeah, me either.

You can’t determine the exact bullet weight just by looking at a cartridge, so most factory ammunition has that figure printed on the packaging. Grains are also used to measure propellant, or gunpowder (not to be confused with individual propellant particles, which are also sometimes called grains). The amount of propellant used in a load is not typically indicated on a box of ammo, and this kind of information is usually only relevant for people who hand load their own ammo. On a box of ammo or online listing, grains nearly always refers to the bullet and not the propellant.

If the bullet weight is not listed on the box, there is often some other clue that can help you figure it out. This is sometimes the case with military surplus ammo, or factory ammo made to mimic a military load. For instance, I have a box of .308 Win. ammo made by CBC. There’s no bullet weight mentioned, but the box is labeled as “M80 ball”. A quick online search shows me that the standard military M80 ball cartridge uses a 147 grain FMJ bullet. Mystery solved.

Know Your Choices

Once you know how to identify the bullet weight, you’ll still need to get a feel for what options you have. For each caliber, there is a range of common bullet weights that will fit most people’s needs, and then a few loads available outside of that range for more specific applications. For instance, most 9mm loads are either 115, 124, or 147 grain, but occasionally you might see a 95 grain, 110 grain, or some other oddball load.

Bullet Weight
A 9mm bullet weighing exactly 124 grains.

If you have an idea of the typical range of bullet weights for the caliber, then you can tell whether any given load falls more toward the heavy end or lighter end of the spectrum. Usually, lighter bullets will have higher velocities than heavier bullets of the same caliber. Intended application and personal preference will dictate whether you need a fast light bullet, a slow heavy bullet, or something in between.

Quick and Dirty Bullet Selection

When you know your options and have an idea of what you plan to do with the ammo, you’re almost there! Simply enter your choice into the magic box below and we’ll tell you exactly which bullet weights are perfect for you…

Oh, my mistake. We’re all out of magic boxes.

I did say there weren’t any easy answers here. In lieu of a magic box, here are a few (very) rough guidelines for choosing the right bullet weight.

Plinking: Bullet weight doesn’t matter much for casual plinking. Just buy whatever ammo is cheapest and functions well in your gun.

Shooting for Maximum Accuracy: Bullet weight can play a huge role in accuracy for a couple of reasons. First, sometimes a specific gun just “likes” bullets of one weight over others. The precise reasons are not always easily explained, but with some experimentation, you might find, for example, that your particular Glock 22 is always a little more accurate with 180 grain .40 S&W loads than 165 grain loads. You might be able to pick up some hints about good loads from other people who have a lot of trigger time with the same gun, but sometimes trial and error might be the only way to figure it out.

For long range rifle shooting, the tie between bullet weight and accuracy is less mysterious, but still potentially confusing. Heavier bullets are less susceptible to being blown off course by the wind, but if the bullet is too heavy, it might not have enough velocity to remain stable at the desired distances.

The best bullet weight to optimize the balance for maximum accuracy will also depend on barrel length, twist rate, and a ton of other factors that we can’t cover here. If you’re serious about pursuing pinpoint accuracy, just ask a long range shooting enthusiast for help and they’ll be more than happy to bore you to tears enlighten you with all the exciting details.

Self-Defense and Hunting: This is a tricky one. Bullet weight is just one of many factors that determine a load’s effectiveness against living targets. For any given caliber, some bullet weights have a better track record than others, but it’s only part of the story. Expansion and penetration characteristics are more important than the mere numbers representing bullet weight, velocity, or caliber. Try to find ballistics gelatin tests or real world reports of a specific load’s performance rather than relying too much on bullet weight as a sole indicator of it’s efficacy.

.38 Special Speer Gold Dot JHP
This Speer Gold Dot .38 Special +P ammo is designed to maximize ballistic performance from short barreled revolvers. The choice of a 135 grain bullet was just one of many factors that Speer took into account when developing this load.

Subsonic/Suppressed: For optimal performance with a sound suppressor, subsonic ammunition is best. These rounds travel slower than the speed of sound, and create minimal noise when fired through a good suppressor. A few calibers that use heavy bullets, like .45 ACP, are almost always subsonic regardless of bullet choice. Other ammo is only subsonic when used with bullets that are heavy for the caliber. For example, the popular .300 Blackout rifle cartridge makes a loud supersonic crack with a factory 125 grain load, even when a suppressor is used on the gun. To get the “silent but deadly” effect that .300 BLK is known for, it must be fired with the heavier 220 grain bullets which travel at slower subsonic velocities.

Bullet Weight vs. Recoil: A lot of people intuitively believe there must be some link between bullet weight and recoil. If I want lighter recoil loads for my handgun, I should choose a lighter bullet weight, right?

Not necessarily.

If the lighter bullets were pushed to the same velocity as the heavier bullets then simple physics would dictate that the recoil impulse would be reduced. But as I mentioned earlier, lighter bullets are usually loaded to fly at greater velocities in order to make up for their low mass. In fact, a high velocity light bullet might even have more recoil than a heavier bullet that’s moving slower. Or… the heavier bullet could have more recoil depending on the load. For example, if the cartridge has a fast burning propelllant, the recoil could hit you all at once, translating to a sharp snap against your hand or shoulder. A slow burning powder might distribute the recoil force over a longer period which feels like softer recoil. There is really just no way to determine what recoil is going to feel like by looking at bullet weight alone.

Does Bullet Weight Even Matter?

If this is the first time you’ve given any thought to bullet weight, you probably still have a lot of questions. You might even still be doubting whether bullet weight is something worth paying attention to at all. The big takeaway is that bullet weight certainly matters, but it’s rarely a reliable sole indicator of whether a given load will fit your needs. At the end of the day, it’s helpful to know what bullet weights are available for your favorite calibers, but you’ll probably have to do some additional digging to find out how each of those bullet weights are used.

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Leave a Comment Below

  • Vernon Russell

    Enjoyed the article. Just one question. Who or what originally decided what weight projectiles were to be used? Always wondered on that one. . . hmmmmm

    • David J Meberg

      Factory ammo loads are developed by the “Factory”. Military loads are determined by the Military. Example, .30-06 started its career as .30-03 but Army wanted a different bullet shape; 7.62 NATO has different loads as does the 5.56 and the boxes are marked with a different M- number to show changes in loads. 5.56 loads used in Viet Nam had a light, fast bullet; as the “need” for an accurate long range load became the norm, heavier, slower loads were developed.

  • Thomas Briggs

    Good review for a newbie, and that’s no small compliment. Misconceptions are even more complicated and could take many articles, as you know (such as heavier bullets are deflected by brush less, which is not true). Kudos to you.

  • Joe Ebert

    Great and thanks for sharing.

  • Jimmy Messer

    I enjoyed the article.One of the things that I think you forgot to mention about bullet weight was a heavier bullet also drops faster than a lighter bullet. last time I went to the range I shot a 150 grain bullet versus 180 grain bullets the 180 grain bullet hit about 10 inches below the 150 grain bullet at 100 yards

    • Allen Smith

      at close range, only thing dropping is gonna be the thug who tries something he shouldnt have

    • David J Meberg

      What was the difference in velocity between the two loads? Unequal speed = unequal results

    • Sam Fisher

      I think it was your aim and you were dropping it, 300 feet is nothing and shouldn’t have dropped at all when the bullet is traveling 800fps+, if you were using a pistol then it has to do with having a short sight radius, or your rifle scope is not sighted in, which maybe the case, you may be using a heavier bullet and it may have a upward arc mid flight. I don’t see a bullet dropping 10 inches at 100 yards.

    • Willie

      This makes no sense!! There can’t be that much drop, unless the velocity is very different!!

  • Gerald Tull

    thanks for the weight comparison. I never seem to be able to remember the grain to ounce ratio

    • Jwedel1231

      7000 grains to a pound, 16 ounces to a pound. I guess it would be 7000/16 (or 437.5) grains per ounce.

  • Oliver Valderrama

    Great info

  • James Poythress

    As informative an article as possible in an area as vague and fickle as bullet weight. Since I am not a military sniper or a competition shooter, I think I will utilized the following, highly inaccurate, rule: Light-Fast, Heavy Slow (LFHS)

  • Floyd Scroggins

    Thanks . I did learn a lot . But for what I do guess it really. Won’t matter that much.

  • Tim Campbell

    Good and Simple Article , I found the imformation helpful and easy to understand ! Thank You.

  • Derrick Skelton

    Very helpful information . Just started reloading. I use 124 xtreme fmj bullets. 4.0 gr of powder. Oal 1.128 to 1.130 . And I use nitro 100 . For my 9mms .

  • Randy

    In a Remington 700, what grain bullet has better knock down power? 130, 140 or 150 grain.

    • Jwedel1231

      Remington 700s come in a large number of calibers. Look on youtube for ammo tests of your caliber and pick something designed for your intended purpose. Also, “knockdown power” is a myth. Look for “kinetic energy” and “energy transfer” as your guides.

  • Ronnie Lee

    Very informative. Why cant we use plastique when it comes to the explosions inside the Bullitt ? Is it possible or not stable enough

    • Jwedel1231

      Modern smokeless powder is not an explosive. It is a very fast burning fuel. As smokeless powder burns and builds pressure, the bullet moves down the barrel to relieve the pressure. If you used an explosive, plastique being a very fast explosive, pressure behind the bullet would build up faster than the bullet can move down the barrel to relieve it and the barrel would fail (explode).

  • Geon Derrico

    I am a newcomer to handguns and after reading this article I STILL haven’t any good reason for deciding between a 147gr and a 124gr 9mm jhp for self defense except that the heavier round makes less noise because it is subsonic.

    If that’s all there is to it why not just say so???

    And I have been looking around the intenet and that’s as conclusive a reason for one rather than the other that I’ve found so far.

    Can anyone add actual reasons for one or the other without mealy mouthing the answer?

    Telling you to choose whatever your gun shoots better is like choosing a wife because of how she fits in your bed.

    As fun as it might be to try them all out, it is costly amusement.

    What rationale can be used before even buying one or the other?

    Should I go with 124gr. Gold Dots simply because that’s what the NYPD has used for years?

    That’s more reason than anything I read in this well intentioned article.

    No offense intended.

    • http://www.luckygunner.com/lounge LG Chris

      You won’t get an easy answer for this because there isn’t one. For self-defense ammo especially, you have to consider every load individually, regardless of bullet weight. This should help: http://www.luckygunner.com/labs/self-defense-ammo-ballistic-tests/

      • Geon Derrico

        So why not just buy the cheapest to begin with, without regard to weight?

        You have to start somewhere as a new shooter. Which do you go for? A heavier bullet?

        If so, WHY???

        If you start with a lighter bullet, again, as a new shooter with zero knowledge of how weight affects recoil or ballistics or penetration and before you know how your virgin gun in your virgin hands will handle the various bullets at the various weights, on what basis do you choose? Do you just close your eyes and hope for the best?

        What are heavier bullets SUPPOSED to shoot like?

        What are lighter bullets SUPPOSED to shoot like?

        Are you so experienced that you can’t remember back to when you had ZERO knowledge of shooting?

        If I asked what the philosophy behind bullet weight was from the manufacturer’s point of view and you told me it was that they made different bullet weights to accommodate guns that might not handle other bullet weights, I will never read your writings again.

        • http://www.luckygunner.com/lounge LG Chris

          The choice of bullet weight depends entirely on the intended use. For casual plinking/target practice with a handgun, sure, just start with whatever is cheapest. If it doesn’t seem to work that well, try a different brand or bullet weight.

          For self-defense ammo, bullet weight should not be the first consideration. Identify a load that has demonstrated good performance in tests or real world use, and start there. Test in your gun for accuracy, recoil, and reliability until you find one that works well. There’s no magic formula for getting it right on the first try because there are just too many variables in play beyond bullet weight alone.

          Lighter bullets travel faster than heavy bullets. A given hollow point bullet design may not open up unless it reaches a certain velocity, so a light bullet might work better since it’s going faster. But it also might fail to expand if it travels *too* fast. Heavier bullets might also have an advantage in greater wounding potential *if* it expands and *if* it’s going fast enough. A fast, heavy bullet would be ideal, but the cartridge case only has so much volume for powder, and the gun is only designed to handle so much pressure.

          Cartridges with heavier bullets often have a longer overall length, which can occasionally cause feeding issues in some semi-autos. Wide-mouthed hollow-point loads can also cause reliability problems, and offering different bullet weights means offering loads with slightly different overall length and shape, which also might affect reliability, depending on the gun.

          A load with a lighter bullet might have less recoil than a load with a heavier bullet. But if the same lighter bullet is a +P load and has extra powder to push it really fast, it might actually have more recoil than the heavier load.

          A short barreled pocket pistol might not have enough barrel length to burn all the powder in one load, so it doesn’t reach optimal velocity and it fails to expand. A different load in that same gun might expand perfectly in gel tests, but it has horrible accuracy. Trying the same two loads in a different gun might yield reverse results.

          So manufacturers experiment with different weights and powder charges and offer a few different loads in a given bullet design, hoping to balance effectiveness with accuracy, felt recoil, and reliable function.

          The only real clue to look for is loads that are specifically optimized for short barrels, if you’re using a compact handgun. But again, that’s not a direct function of bullet weight, but rather the bullet weight in conjunction with the amount of powder and type of powder the manufacturer uses.

          Once you’ve identified a self-defense load that works well in your gun, you might want a practice load that has a similar recoil impluse and hits to the same point of aim as your defensive ammo. Trying FMJ loads from the same manufacturer with the same bullet weight is a good starting point.

          But this is about as close as we can get to a systematic method for selecting a load solely based on bullet weight. Otherwise, it just requires trial and error.

          If you’d like a starting point, the 124 grain Gold Dot you mentioned is a great load, as are any of the Federal HST loads, or any of the other loads that performed well in our gelatin tests. Try a couple of boxes of the Gold Dot in your gun, and if it’s from a quality manufacturer and made in the last 20 years, chances are very good that it will work just fine.

  • Paul Bernard

    this was a very informative article. I have owned hand guns for one year and shoot every week. I often wondered how grain would affect recoil, and now have a better idea of how and why.