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What Can Affect the Performance of a Bullet

02.12.2022

There are a great many things that go into ammunition performance. Some related to the round and the firearm, and some related to the conditions in the world around the firearm.

These things can largely be sorted into three categories: internal effects, external effects, and terminal ballistics.

By internal effects, we mean the things related to the round and the firearm themselves. By external effects, we’re talking about the conditions in which the ammunition exists, primarily how it’s stored and where the bullet is fired.

Terminal ballistics is specifically how the projectile acts once it hits the target. This largely has to do with bullet design and impact velocity which will be discussed with internal effects.

Let’s take a look at two categories of effects, external and internal, and how they impact the way your ammo performs in the field, so you can get the best performance possible out of your rounds.

Internal Effects: 

Ammunition Quality 

First and foremost, the actual manufacturing quality and precision that goes into making your ammo is a big part of any round’s performance. The reason high-quality rounds are so expensive is because of the quality of materials, and the amount of care that goes into crafting them.

Precision ammunition is made to very exacting standards, with very consistent bullet shapes, powder loads, and seating depth to give you the shot-to-shot consistency required for long-range ammunition.

Quality is also a key part of high-performance big bore ammo used for big and dangerous game hunting. Rounds like our .375 H&H solid slugs require precision manufacturing to achieve the right effect down range.

After all, the last thing you want is an angry buffalo or brown bear charging you because you cheaped out on your ammunition and it wasn’t quite up to the task at hand. Trust Grizzly Ammunition for second-to-none quality bullets and cartridges.

Bullet Design

The bullet weight, ballistic coefficient, and sectional density of a round all have a big impact on performance, particularly at longer ranges. A heavier bullet with a higher ballistic coefficient will be able to fight the wind and the effects of air resistance much better than a lighter, lower BC round.

On the other hand, a lighter bullet will have a higher velocity, which also helps fight drop. This is why you see a lot of longer, lighter-weight bullets used in things like Precision Rifle Competition. A long skinny round has a higher ballistic coefficient and a higher velocity which makes for a greater distance.

If you’re worried about the performance against a soft target, then often a hollow point or expanding round is preferred, as these rounds are designed to open up when hitting a soft material. Rounds like our .380 AUTO +P 50gr XTREME© Fragmenting HP are designed to open up and fragment on impact.

A selection of bullets isolated on white.

This creates a larger and deeper wound channel, causing more collateral damage to vital organs, which allows high-quality defensive ammo and hunting rounds to punch above their weight class in terms of damage done to a living target. The same thought process goes for self-defense

Barrel Length

Barrel length also impacts a round’s performance. Every round has a minimum barrel length needed to complete the combustion process and burn all its powder, and anything under that length will mean you’re getting less velocity than you otherwise could be.

Losing velocity means more drop and drift, as well as worse performance when striking a game animal or human threat.

Close up of gun barrel on the wooden table

Increasing velocity is one of the most important things you can do for bullet performance, so make sure you have a longer barrel that is adequate for the round you’re shooting, or you’re okay with the performance tradeoffs.

 

External Effects:

External effects, also known as external ballistics, consider a wide variety of factors that can affect your shot’s velocity and trajectory, including but not limited to, altitude, air temperature, moisture, gravity, and wind velocity. For a beginner, these external factors may not be common sense yet, but they can all have either positive or negative effects on the performance of a bullet.

Altitude

You probably already know that at higher altitudes, there’s less pressure and the air is thinner, but you may not have thought about how that impacts ballistic performance.

At high altitudes, bullets encounter less air resistance, reducing drag. This means that despite having the same muzzle velocity, bullets maintain their velocity better and you’ll experience less bullet drop.

So, when shooting at a different altitude than you normally do, you’ll want to re-zero your optic before you get started. This also means that a round will lose less velocity at higher altitudes. This gives you less drop and drift, and generally better performance.

How much this matters is really down to the distance you’re shooting at though, and at 100 yards you aren’t going to see a difference whether you are at sea level or not. Long-range precision shooters will definitely see a severe difference with large elevation changes however and have to take this into account.

Temperature

When we say that temperature can affect the performance of a bullet, we mean that in a few ways.

First, the ambient temperature of the air can impact ballistics in similar ways to altitude. In fact, just like higher altitudes, warmer temperatures lead to lower air density, so less drag and less bullet drop.

Second, the temperature can also affect the burn rate of gunpowder. This is less true than it used to be since the vast majority of ammunition now uses temperature-stable powder.

However, with some cartridges, especially older ones, hotter temperatures can mean that the powder burns faster, which can result in greater velocity. How much faster depends on the powder and the exact temperature, as well as barrel length. Generally, this isn’t enough to matter.

The last and most important way that temperature affects bullets is more related to the temperature at which ammo is stored, since improper storage can damage ammo,

Ideally, ammunition should be stored between about 55°F and 85°F, but a little outside those ranges isn’t the end of the world.

Extreme temperatures are where it becomes a problem, especially high heat. Ammo should never be kept in temperatures over 150°F. Generally, it’s easy to avoid temperatures like that by simply not storing your ammo in a car during the summer months. Otherwise, exposure to these types of temperatures is rare.

Extreme cold can also be a problem, but less so than extreme heat. Still, it’s a good idea to not store ammo in an unheated shed or similar space if you live somewhere that gets very cold in the winter.

In fact, try to store ammo in a climate-controlled space in general, since the more common issue for most gun owners is temperature fluctuations. That means avoiding keeping ammo in cars, garages, and other places that don’t have consistent climate control.

Moisture

Similar to temperature, moisture can affect bullet performance in a couple of different ways.

First, humidity impacts ballistics. The more humidity in the air, the denser it is. As we’ve already established, denser air means more drag and more bullet drop.

The effect of humidity is more noticeable in longer distance shooting, but the impact is still so negligible that your optic’s turrets probably don’t have a small enough adjustment interval to account for it.

Secondly, and more importantly, exposure to moisture can damage a round of ammo, most commonly through corrosion.

For this reason, ammunition should be stored in a dry, well-ventilated space. Skip garages and outbuildings, especially if you live somewhere humid. Gun safes are usually a safe bet. For extra protection from humidity, store your ammo near a dehumidifier or in a sealed container with a desiccant.

Grab a big jar of silica gel packs (the DO NOT EAT ones that come with new shoes) and throw a handful in with your ammo or get a gun safe dehumidifier. Your guns will be happier with that arrangement too.

Gravity

What goes up must come down, and that includes bullets. Gravity drags your bullet towards the earth from the moment it leaves the barrel, altering the trajectory of the round and slowing it as it dragged through the air.

This isn’t an issue at close ranges with rifle calibers, but it’s something you have to consider at longer ranges. And with slugs and pistol calibers you’ll feel the effects of gravity even inside 100 meters.

Fortunately, gravity is a constant everywhere in the universe, so it’s actually fairly easy to account for its effect on a bullet’s trajectory as it moves towards the target. There are quite a few ballistics calculators that will do all the math for you, and many rifle rounds will just have a drop chart on the back of the box you can use.

Wind Velocity & Direction

Lastly, the velocity and direction of the wind can play a huge part in where a bullet ends up, especially at longer ranges.

At close ranges, you can effectively ignore the wind, but once you start reaching out to 500 meters or more, you’re quickly going to have to learn how to gauge both the velocity and direction of the wind, as well as how to account for it and adjust your aim accordingly.