AN ABBREVIATED LESSON ABOUT BULLET WEIGHT

Are higher grain bullets always better? C'mon, we are Americans, so bigger is always better. Well, for the most part anyway, but there are exceptions in every generalization. Let's start with the basics.

WHAT IS A GRAIN?

Bullet weight is calculated with a very basic unit of measurement; grains. One unit of grain is equivalent to 1 (one) 7,000ths of a pound, or in other words, it takes 7,000 grains to make up a pound. The granular weight of the bullet can be found on the manufacturer's box, mostly always before the bullet classification. The grain measurement is frequently abbreviated as "gr." An example is 40S&W 180gr. FMJ translates into a 40 S&W Full Metal Jacketed round with a 180-grain bullet.

HOW DOES BULLET WEIGHT AFFECT BULLET PERFORMANCE?

Two important factors to consider when selecting a bullet weight are accuracy of the flight path; trajectory, and how the bullet reacts upon striking the target; terminal ballistics. The skinny of it is a smaller grain bullet can offer faster travel of greater distances while maintaining a straight flight path. So why would anyone choose a heavier bullet then? The fact of the matter is, a lot can go wrong with a lighter-weight bullet during its flight to the target. Typically you have less energy behind a lightweight bullet, so natural elements such as wind can easily blow it off target. But that doesn't necessarily mean that a heavier bullet is better either.

Sar USA 9mm 124gr FMJ Ammo

Field Test: HST Velocity & Energy

To understand these points, let's look at two products from Federal Ammunition. This ammo is from the same brand, loaded with the same bullet. So, what does a 23-grain differential mean for the speed of the bullet when it leaves the end of the barrel (muzzle velocity)? 124 Grain/147 Grain Shot 1 1082 fps 949 fps Shot 2 1082 fps 922 fps Shot 3 1064 fps 954 fps Shot 4 1065 fps 939 fps Shot 5 1073 fps 935 fps The average for the 124 gr. bullet 1073 fps. Calculating the muzzle energy for this distance with a 125gr. bullet will give you 317-foot pounds of energy. The calculation for the 147gr. bullet is a little under 940 fps. giving the shooter only 288-foot pounds of energy. This example flies in the face of the argument that bigger bullets have more energy behind them. In this instance, the lighter bullet of the two traveled faster AND delivered more energy. But this is only one example, and any other chosen combination could have resulted in an opposite scenario. Smaller bullets are great for shooting targets, after all that's what the shooter wants for this activity; speed and distance. Although wind can interfere with a smaller bullet's trajectory, it is likely to get to the target before that happens. Common sense tells us that a heavier bullet will drop faster, leaving the lighter bullet with a straighter flight path. The more stable and straight the flight path, the longer distance the smaller bullet will travel.

CHOOSING A BULLET WEIGHT

I'll bet the above comparison made you think a little. Don't worry though, your decision to select a heavier bullet for your needs is likely the right decision after all. In a bullet's performance, this is where the rubber meets the road. I am talking about terminal velocity. This is what counts. For both hunting and home or self-defense, you want to deliver more energy INTO your target. The above comparison between lightweight and heavier weight bullets focuses on speed during travel, and some energy on the target. However, in home defense, you want enough penetration to stop the threat. In hunting, you want enough penetration for a quick and humane kill. Of course, there are other variables, such as the shape, type, and expansion, that play into a successful penetration, but the weight of the bullet and the velocity behind it drive the depth of penetration. Simply put, heavier bullets deliver more energy INTO the target.

Belom 7.62x39 123gr FMJ Ammunition

THE MOST ASKED QUESTION

Believe it or not, speed, distance, and terminal ballistics is not the first question that I am ever asked about the difference in bullet weight. The most asked question when it comes to bullet weight is "will the bullet weight affect the recoil". The answer is an absolute - yes. We usually refer to the old adage of "for every action there is an equal and opposite reaction" when we talk about recoil. Although we may not put a lot of thought into that, it actually has a lot to do with bullet weight. Other factors should also be taken into consideration, such as the powder load and the length of the barrel, and even the weight of the firearm. For the sake of this article though, let me explain how bullet weight affects recoil. Because the force, due to the velocity of lighter bullets, returns very quickly to the shooter, you often hear that this causes a hard kick. Whereas the recoil from a heavier bullet feels different and actually comes from a different source. The expanding gases behind the bullet as it travels down the barrel has to work much harder than they would for a lighter bullet. This causes a more noticeable felt force because the gases are pushing back harder on the firearm.

IS A HIGHER GRAIN BULLET BETTER?

If personal or home defense is your goal, I would go with a heavier bullet because of the penetration and energy INTO the target. For long-range target shooting, plinking, or garden varmints, a smaller grain bullet will work great because of better energy DURING flight and AT the target. Shop All Ammunition