The Effects of Cold Weather on Guns and Ammo

December 4, 2023
Guns In Cold Weather

Have you ever taken a firearm to an indoor range, tested it, found it runs flawlessly, and then experienced problems when you took it outside in the cold? You may have experienced cold weather performance issues. Numerous gun owners live in conditions where these problems can happen, from hunting during the colder months to living in states with cold or freezing winters.

Guns in cold weather perform differently than at room temperature, impacting their performance in various ways. From reduced ammunition efficiency to changes in ergonomics, understanding how the cold affects your guns and ammo will help you prevent malfunctions, discomfort, or excessive wear and tear.

How Cold Affects Ammunition

The effect of cold weather you are most likely to notice on your firearms is extreme temperatures affecting your ammunition. While low temperatures are generally unlikely to cause malfunctions with quality factory ammo, they can change its performance.

Modern ammunition is loaded using smokeless powder, a successor to traditional blackpowder and transitional propellants, such as cordite. Smokeless powder burns faster in hot temperatures and slower under colder conditions. The exact variations depend on the cartridge’s caliber, the loaded powder type, and the outside temperature.

When fired under conditions colder than room temperature, the performance of your ammunition is affected in two ways:

Lower Chamber Pressure

Slower-burning powder results in a slower conversion of gunpowder to gases when firing the cartridge. This causes the pressure inside your gun’s chamber to be lower than at room temperature. While this may reduce your firearm’s long-term wear and tear, it can also lead to less consistent performance of your weapon and ammunition with each shot.

Decreased Bullet Velocity

A side effect of a lower chamber pressure is lower bullet acceleration. Less pressure pushing the bullet out of your gun’s barrel results in a lower muzzle velocity. The pressure difference can affect its trajectory and point of impact (POI), changing your gun’s accuracy and precision.

  • Example: Norma .30-06 Jaktmatch Test

    For instance, an ammunition test conducted by Norma tested .30-06 Jaktmatch hunting cartridges stored at three different temperatures:

    • Cartridges stored at room temperature (20°C or 70°F)
    • Cartridges stored outside in Scandinavia (-2°C or 28.4°F)
    • Cartridges stored in a freezer (-18°C or -0.4°F)

Each of the three types performed differently when shot from a rifle with a 22-inch barrel.

  • Room-temperature ammo. The average muzzle velocity was 2,625 ft/s, and its POIs were used as a baseline.
  • Ammo stored outside. The POIs on these projectiles shifted down and to the right, and the average muzzle velocity dropped to 2,575 ft/s or about 50 ft/s less.
  • Freezer ammo. The POI shifted further down and to the right, and the average muzzle velocity lowered to about 2,533 ft/s or about 92 ft/s under the room-temperature ammo.

These results indicate that while the reduction in muzzle velocity isn’t significant enough to affect the bullet’s lethality, the cold can affect your ability to shoot accurately. While the difference may be less pronounced at shorter distances, such as with handguns or shotguns, temperature becomes a factor when shooting rifles, especially hunting or precision target shooting rifles.

Always zero your rifle, optics, and ammunition in the weather conditions you expect to shoot at. Relying on a rifle that was zeroed indoors or at room temperature can cause your point of impact to deviate significantly from your point of aim.

Experienced winter hunters carry spare ammunition in an inside chest pocket, exposing it to their body heat. It can help ensure their cartridges are slightly warmer than outdoor temperatures and mitigate the risk of POI shifting.

Does Cold Affect Ammunition Reliability?

Modern manufactured ammunition typically features sealants to protect it from moisture, condensation, and frost, ensuring it doesn’t contaminate the primer or propellant.

They reduce the risk of a misfire or a malfunction when shooting, including under extremely cold conditions. For instance, all ammunition tested during the Norma test fired successfully and caused no malfunctions.

However, no ammunition is 100% fail-safe. There is always a possibility of malfunctions related to ammunition when shooting in cold conditions.

Cold Weather Affects Your Firearms

How Cold Weather Affects Your Firearms

Although modern firearms are engineered to function across various temperatures, known as operating temperatures, cold and frigid conditions can alter their performance, the dependability of their action and mechanisms, and impact their accessories.

Cold Weather and Metal Surfaces

One of the primary risks of shooting guns in cold weather is the effects of cold on metal surfaces, such as steel and aluminum. These materials are thermally conductive, transmitting heat or cold more efficiently than other materials.

Touching a steel barrel or aluminum components in the cold with your bare hands can be uncomfortable and dangerous, potentially causing cold burns. Always wear winter-safe gloves and hold your guns’ wood or synthetic parts whenever possible.

However, not every firearm is intended for use with gloves. Ensure you can comfortably handle and fire your firearms while wearing gloves. Switching to a different firearm or opting for lighter, slimmer gloves may be necessary if difficulties arise. This is especially crucial for handguns, as the amount of space in the trigger guard for a gloved finger varies by model.

These factors can change the amount of space available in the trigger guard:

  • The size and design of your trigger and trigger guard
  • Whether your trigger is in the cocked or uncocked position
  • Whether your handgun features a trigger-mounted safety

Condensation and Sweating Guns

If you’ve been carrying a firearm openly in the winter or cold conditions all day, entering a home or heated shelter soon afterward can cause condensation to appear on the surface of your gun. This phenomenon is sometimes referred to as “sweating.”

Bringing a sweating gun back outside can cause the condensation to freeze again. If the condensation has formed on moving parts or internal mechanisms, it may cause malfunctions or reliability issues.

According to U.S. Army Field Manual 31-70, the sweating effect can last as much as one hour. If you intend to bring your firearm back outside, allow it to finish sweating first. Then, field-strip it, clean and lubricate all essential moving parts, and reassemble it before returning outside.

Effects of Cold on Gun-Mounted Accessories

Most modern firearms are compatible with various accessories, from scopes to tactical lights. Cold weather can affect their performance. Here are some of the most common issues to watch out for:

  • Battery-powered accessories. Laser sights, tactical lights, red dot sights, holographic sights, and certain types of scopes may be powered using batteries. The lower the temperature, the more a battery’s performance will degrade, reducing its capacity and shortening the life of your battery-powered accessories.
    On average, a battery designed to operate optimally at 80°F will lose 50% of its capacity at 0°F. Consider bringing spare batteries and storing them in a warm area if you intend to use such gun accessories for extended periods in the cold.
  • Optical devices. Accessories relying on lenses, such as scopes and red dot sights, may be affected by condensation. While many modern scopes feature anti-fogging features, such as nitrogen purging or anti-fog coatings, condensation can cause your lenses to fog up and reduce visibility.
    Consider bringing a microfiber cloth to gently wipe the surface of your lenses and allow your scope to acclimate to the outdoor temperatures. You can also use lens caps with see-through ends to protect your lenses from contact with snow or ungloved fingers, which can leave residues or scratch their surface.

Cold Weather Gun Maintenance Considerations

Cleaning your guns in cold weather requires special care and dedicated cold-weather cleaning solutions and lubricants. Standard gun lubricants typically aren’t designed to function in extreme temperatures.

In cold conditions, the viscosity of a typical gun lube increases, sometimes turning into a thicker and gummier substance. This can harm the safe operation of your firearms and jam your gun’s moving parts.

To prepare your guns for cold weather usage, follow these steps:

  • Field-strip every firearm you intend to use in cold weather for extended periods.
  • Use 91% isopropyl alcohol or a similar gun solvent to remove previous lubricants from the surfaces of your gun parts. Do not skip this step, as you should not mix different types of lubricants on the same firearm. Doing so risks increasing the risk of jamming or creating malfunctions.
  • Once your gun parts are free of non-cold weather-rated lubricants, apply a layer of cold weather-safe lube. Many commercially available lubricants, such as Break-Free CLP or Hornady One Shot, are safe for low temperatures.
    You may also consider non-oil-based options, such as small quantities of powdered graphite. They do not thicken or become a gummy substance with changing temperatures nor attract dust or grit like liquid or viscous oils.
  • Carefully apply small quantities of the lubricant of your choice. Avoid over-lubing, and don’t bathe all your gun parts in it. Some parts, such as the fire control group, trigger assembly, firing pin channel, sears, and strikers, can be cleaned but are not designed to be lubricated. This is because of the high risk of lubricants attracting grit and turning into malfunction-creating grime.

Prepare for the Cold Months with IFA Tactical

As proud Michiganders, the team at IFA Tactical can assist with all your winter firearm needs. We can help you ensure you can shoot your guns in cold weather as safely as possible.

Browse our large selection of firearms, ammunition, accessories, gun cleaning supplies, and lubricants. Many of our products are manufactured by companies with extensive experience producing cold weather-safe products.

Whether you need a reliable H&K or SIG Sauer rifle, a nitrogen-purged Leupold or Schmidt & Bender scope, or the best low-temperature lubes, we carry the items you need.

Contact us today for any questions regarding winter shooting and gun maintenance.

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