Under Pressure

Share on Social Share on Facebook Share on Twitter

hunter ejecting a shot case from a rifle

For most people, barometric pressure is just a number on the weather they ignore in favor of more practical day-to-day info on rain, temperature and wind. But for the long-range shooter, pressure is a significant factor in making solid hits. There’s no better way to factor in the barometric pressure than by using Ballistic, the No. 1 long-range shooting app.

Barometric pressure, also called atmospheric pressure, is the amount of pressure in the air at given place and time. The Earth is surrounded by a layer of gases called the atmosphere. At sea level, this layer is at its thickest (extending from the surface of the ocean to atmosphere’s uppermost layer), and this equates to higher barometric pressure than at the top of a mountain where there is less atmosphere above.

Barometric pressure is often measured in inches of mercury (inHg). The higher the number, the higher the barometric pressure, and vice-versa. Weather fronts moving in or out can also greatly affect barometric pressure.

The Effect

What does all this mean for the long-distance shooter? Well, at a higher pressure, a bullet experiences more resistance. Therefore, it will slow more rapidly and drop more than the same bullet launched at the same speed at lower pressure.

landscape of a hill

In real-world numbers, consider the trajectory of a typical 140-grain 6.5 Creedmoor load with a muzzle velocity of 2,710 feet per second fired through a rifle zeroed at 100 yards. With a barometric pressure of 25 inHg (typical for 5,000 ft altitude – think: Denver, CO), the bullet’s point of impact at 1,000 yards will be nearly 30 inches higher than at a barometric pressure of 30 inHg (typical for sea level – think: Houston, TX). That’s huge!

The Solution

Fortunately, the Ballistic app lets you update your Atmospheric Conditions based on where you’re shooting and as weather fronts move in and out. Ballistic will automatically recalibrate your projectile’s trajectory based on the atmospheric inputs and changes to those inputs, placing you on target no matter the conditions.

Gold Medal Sierra MatchKing

Federal’s exclusive primer design provides the best sensitivity and most consistent ballistics in the industry. Combined with the precision-built Sierra MatchKing, these loads are the top choice for the world's most elite shooters.

Buy Now

Gold Medal Sierra MatchKing Packaging and Cartridges