Can You Expect Your Gun To Hold Its Zero In Extreme Temperatures?

by
posted on December 6, 2017
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
temperture-zeros1.jpg

The temperature of the powder in ammunition at the moment of ignition has a significant effect on both chamber pressure and muzzle velocity. If a gun is fired in an environment radically hotter or colder than the one in which it was originally sighted-in, the muzzle velocity of the bullet can be significantly different. Of course, the difference in muzzle velocity changes the bullet’s trajectory. Some powders are more sensitive to changes in temperature than others. Only the manufacturer of a particular propellant can put a number on its sensitivity. But, a shooter or handloader can use a ballistics program to explore a particular bullet’s sensitivity to changes in muzzle velocity.

Generally speaking, higher temperatures boost pressure and velocity, while lower temperature decrease pressure and velocity. Shooters should remember that ammunition exposed to direct sunlight will reach a temperature much higher than that of the surrounding air. Even worse are the conditions found within the trunk of an automobile—especially one that has a dark colored interior—when exposed to the desert sun in one of the southwestern states. This type of exposure has been known to cause misfires. In contrast, extremely cold temperatures can cause erratic or inadequate ignition.

Given these variables, shooters would be well-advised to do everything they can to protect their ammunition from extreme temperatures. Zeroing your gun at home under conditions you expect to find at your destination is a good idea, but it is not always practical. Competitors should expect a shift in zero after traveling a long distance or experiencing a change in weather. Never pass up a chance to sight-in and confirm your zero.

Latest

2025 Usashooting Pistolnationals 1A
2025 Usashooting Pistolnationals 1A

Klemp, Tobar Win Big At 2025 USA Shooting Pistol Nationals

Marcus Klemp and Nathalia Tobar emerged as champions in the men’s and women’s 10m air pistol events at the 2025 USA Shooting National Championships in Anniston, Ala.

Review: Ruger 10/22 Carbon Fiber

Precision meets speed: Ruger’s 10/22 Carbon Fiber raises the bar for rimfire competition, especially Steel Challenge.

Winstead-Severin Outlasts Field To Win 2025 Iron Man Silhouette Championship In Montana

Cathy Winstead-Severin clinches 2025 Iron Man Silhouette Regional Championship in Missoula, Montana, showcasing elite endurance and precision over two grueling days of competition.

A New Generation Rises At Close Of 1970s: 1979 National Matches

New champions emerge as legends endure in a defining year at Camp Perry.

NRA America’s Rifle Challenge Takes Center Stage On Shooting USA

Shooting USA heads to Camp Atterbury for a deep dive into the NRA’s latest action shooting format, designed for both new and seasoned AR-15 competitors.

Springfield Armory 1911 AOS Series Showdown

Springfield Armory’s modern 1911s—TRP AOS, Ronin AOS and Operator AOS—go head-to-head in a 1911 AOS series showdown.

Interests



Get the best of Shooting Sports USA delivered to your inbox.