VELOCITY PART 2

We’ll continue to push the envelope in testing, and we’ll keep you informed about any changes as we navigate the ever-evolving landscape of powder, primers, and ballistics. After all, it’s not just about making ammo—it’s about making the best ammo for you.

The Environmental Impact on Muzzle Velocities

When it comes to ammunition performance, environmental factors play a crucial role in determining muzzle velocity. While we often think of velocity as a static number, the truth is that it fluctuates based on a variety of external conditions. These factors—temperature, altitude, humidity, and even atmospheric pressure—can all influence how quickly a bullet leaves the barrel. Understanding these variables is important for shooters who want to optimize their performance, whether at the range or in the field.

Let’s take a deeper dive into how these environmental conditions affect muzzle velocities.

1. Temperature: Hot vs. Cold

Temperature is arguably the most significant environmental factor that impacts muzzle velocity.

• Hot Weather: In hot conditions, both the powder and the air expand, which generally leads to an increase in velocity. As temperatures rise, the propellant burns more quickly, generating more pressure behind the projectile. This can lead to slightly higher velocities, especially with high-temperature stable powders.

  For example, when temperatures increase, you may notice that your chronograph readings are higher than what you see in cooler weather. This is due to the faster burn rate of the powder in hot conditions, which creates more gas pressure and pushes the bullet out of the barrel at a higher speed. However, this effect is generally not extreme, and many modern powders are formulated to minimize this variability.

• Cold Weather: On the flip side, cold temperatures can slow down the burn rate of the powder. This results in lower muzzle velocities, as the powder doesn’t generate as much gas pressure in colder conditions. In frigid temperatures, you may see a noticeable drop in velocity, which can affect accuracy and trajectory, especially at longer ranges. Cold temperatures also cause the air to become denser, which can create additional drag on the bullet, slowing it further.

  This is one of the reasons why hunters in colder climates might see less punch or energy from their rounds in the field during winter months. A drop in temperature can result in a loss of energy at impact, which could be a factor when hunting predators or big game.

Key Takeaway: Always consider temperature when testing or using ammunition. If you're shooting in extreme heat or cold, be aware that your velocities might deviate from the published averages.

2. Altitude: Higher Elevations and Muzzle Velocity

Altitude can dramatically affect both the pressure behind the bullet and the density of the air, which influences velocity and trajectory.

• High Altitudes: At higher elevations, the atmospheric pressure decreases, and the air becomes thinner. This lower air density reduces the drag on the bullet, meaning the projectile can travel further with less resistance. However, lower atmospheric pressure also means less oxygen for combustion, which can affect the burn rate of the powder. In high-altitude areas, you may see a slight decrease in velocity as the lower pressure means the propellant burns less efficiently.

  However, the thinner air at high altitudes can offset this loss of powder efficiency to some extent by allowing the bullet to maintain velocity over longer distances, as drag is reduced.

• Low Altitudes: In contrast, at lower elevations, the air is denser, creating more resistance and slowing the bullet's flight. The higher atmospheric pressure can help the powder burn more efficiently, potentially boosting velocity slightly, but the increase in air resistance at sea level means the bullet's energy is dissipated more quickly.

Key Takeaway: Muzzle velocity can be slightly higher at sea level due to the denser air aiding in combustion efficiency, but the higher air resistance at lower elevations can offset that increase. Shooters in mountainous areas or at high elevations should expect to see different ballistics compared to those at sea level.

3. Humidity: Moisture in the Air

Humidity may not seem like a major factor, but it can subtly affect both powder performance and the flight characteristics of a bullet.

• High Humidity: When the air is more humid, it contains more water vapor, which can slightly reduce the burn rate of the powder. While this effect is usually minimal, in extreme conditions—such as high humidity in warmer weather—the ammunition may burn a bit slower, leading to lower muzzle velocities. The increased moisture content in the air also makes the air denser, which could increase drag on the bullet and slow it down in flight.
• Low Humidity: In contrast, low humidity can help maintain a more consistent burn rate, potentially boosting velocity slightly. Dry air tends to be less dense, which reduces drag on the bullet and allows it to maintain velocity over longer distances. While the impact of humidity is usually less pronounced than temperature or altitude, in certain conditions, especially in very humid or dry climates, it can have an effect on overall performance.

Key Takeaway: High humidity can reduce muzzle velocity and cause a slight increase in air resistance, while low humidity can allow the bullet to travel more efficiently and potentially increase velocity.

4. Barometric Pressure: The Weight of the Air

Barometric pressure, or the weight of the air, can also affect the burn rate of the powder.

• High Barometric Pressure: When barometric pressure is high, the air is denser, which leads to increased resistance against the bullet in flight. Higher pressure can also aid in more complete combustion of the powder, resulting in higher velocity as more pressure is generated in the chamber.
• Low Barometric Pressure: Conversely, low pressure—such as on a stormy day—means the air is thinner, and while this reduces the drag on the bullet, it can also cause the powder to burn more slowly, which could lower the velocity. Low pressure can also lead to unpredictable results, as the atmosphere itself becomes unstable.

Key Takeaway: Barometric pressure can affect both the velocity of the round and its trajectory. In high-pressure conditions, you might experience slightly higher muzzle velocities and a flatter trajectory, while low pressure may cause a drop in velocity and more pronounced bullet drop over distance.

5. Wind: The Invisible Force

While wind doesn't directly impact muzzle velocity in the same way temperature or altitude does, it’s still an important environmental factor to consider when shooting at longer distances. Wind can affect the bullet’s trajectory, causing it to drift left or right, or even up and down, based on the wind speed and direction. While it doesn't change the speed at which the bullet leaves the barrel, it can certainly affect the bullet’s path after it’s been fired.

Conclusion: The Environmental Equation

Ultimately, velocity is not a fixed value—it’s influenced by a variety of environmental conditions. Temperature, altitude, humidity, barometric pressure, and even wind all play a role in determining how fast a bullet travels and how it behaves once it's in flight.

At Ally Munitions, we take these factors into account when testing and developing our ammunition. We strive for consistency and accuracy, but we also acknowledge that environmental conditions will always have some effect on the performance of a round. That’s why we encourage all shooters to take their specific environmental conditions into account, chronograph their rounds, and adjust for changes as needed.

While we can’t eliminate the impact of these variables, we can help you understand them and adjust your expectations for better shooting performance in any conditions

Minimizing Velocity Swings: What You Can Do

One of the most common challenges in ammunition performance is managing the fluctuations in muzzle velocity caused by environmental factors like temperature and humidity. While we can't completely eliminate these factors, there are steps you can take to minimize their impact and keep your ammo performing consistently.

Moisture Control: Sealed Containers & Silica Packs

At Ally Munitions, we take steps to mitigate one of the primary factors that can affect velocity—moisture. Powder, like a sponge, is highly susceptible to absorbing moisture from the air. This can alter its burn rate, leading to inconsistent velocities, especially over time. To combat this, we’ve moved aggressively toward more sealed containers for our hunting ammunition, especially for products that are exposed to a wide range of conditions. We also include silica gel packs in the packaging, which help absorb any moisture that might sneak in. While it’s impossible to create a completely airtight seal in our ammo containers (and most ammunition manufacturers face this challenge), these steps go a long way in preserving the integrity of the powder.

Proper Storage: A good rule of thumb is to keep ammo stored in a cool, dry place whenever possible. If you want to extend the shelf life and maintain consistent performance, tightly screw the lid back on your ammo containers after use and ensure they are stored in an area that avoids excessive humidity or extreme temperature swings. This is particularly important for hunting ammo, which often sits in your gear for extended periods before use.

The Impact of Temperature on Velocity

Temperature is a major culprit when it comes to velocity changes, and we’ve recorded a range of results based on our extensive testing. On average, we’ve seen anywhere from a 0.5 to 1.5 fps decrease in muzzle velocity per degree of temperature change. This is a significant fluctuation when shooting at longer ranges, as small variations in velocity can impact your point of impact.

This temperature-based variance is not static—it varies across different loads, powders, and bullet types. Some of our loads are more temperature-sensitive than others, but we make it a point to specify how each load performs based on our testing results. For instance, if a load is more sensitive to temperature fluctuations, we will note this on the product description so shooters are aware of potential performance changes in hot or cold weather.

Key Takeaway: Temperature will always affect velocity, but through proper ammo storage and careful attention to how your ammo reacts in various conditions, you can minimize those effects.

The Myth of "Temperature-Stable" Powder

A common claim in the industry is that some powders are “temperature-stable”, meaning they are less affected by fluctuations in environmental temperature. While some powders are more stable than others, the idea that a powder is completely immune to temperature changes is simply not true. In reality, powders do react to temperature—it’s just that some do it to a lesser degree than others.

As we’ve mentioned, temperature increases tend to speed up the burn rate of powder, which can lead to faster muzzle velocities, while colder temperatures slow down combustion, reducing velocity. There are powders that perform better in extreme temperatures, but no powder is entirely immune to environmental factors.

We plan to delve deeper into this topic and provide more information in a future post, where we’ll explore the nuances of powder performance in hot vs. cold climates, and break down the science behind it. But for now, just know that claims of "temperature-stable" powders are largely overblown—some powders are simply better at maintaining consistency across temperature ranges, but they all change to some degree.

Looking to the Future: More Data, More Precision

We are constantly evolving and expanding our testing methods to bring you even more precise, real-world data. In the coming months, we’re setting up additional satellite test facilities in various states, from higher elevations to areas with more extreme humidity. This will allow us to expand our testing range and collect more accurate, region-specific data to help understand how different powders perform in diverse environments.

This will give us the opportunity to study how our powders react at higher elevations, where air density is thinner, and how they perform in areas with higher humidity, where moisture can have a more profound effect on performance. It’s all about collecting more data—and more "nerd stuff" as we like to call it—so that we can continue to refine our products and deliver better ammunition that performs as consistently as possible, no matter the conditions you’re shooting in.

Key Takeaway: We're committed to ongoing research and testing in the real world so we can better serve our customers with ammo that performs accurately and reliably. We want you to have the most comprehensive, up-to-date information available, so you can make the best choices for your shooting needs.

Conclusion: Managing Environmental Variability

At the end of the day, velocity swings caused by environmental factors are a reality every shooter faces. Temperature, humidity, and storage conditions all play a role in how ammo performs, but there are steps you can take to minimize these fluctuations. Proper ammo storage, the use of silica packs, and understanding the nature of powder behavior in different conditions can all help you achieve more consistent shooting results.

We at Ally Munitions are committed to minimizing these variations as much as possible. We continue to test and refine our loads, and we strive to provide you with the most accurate and consistent ammunition available. By collecting more data and expanding our testing programs, we’ll be able to give you even more precise performance metrics and offer even better ammo for every shooting environment.

As always, our goal is simple: To provide the best ammunition with the most accurate real-world data, so you can rely on our products no matter where or when you’re shooting