Can Cold Weather Cause Scope Zero Shifting?

Thermal Expansion and Contraction

Cold weather causes a rifle’s barrel and scope mounts to contract, which can shift the point of impact. This is because most rifle barrels and scope mounts are made from metal, which expands and contracts with temperature changes. A 50°F (10°C) drop in temperature can cause a 0.01-0.02 inch (0.25-0.5 mm) contraction of the barrel, resulting in a 1-2 MOA shift in the point of impact.

Measuring and Adjusting for Zero Shift

To compensate for zero shift, hunters and shooters need to measure and adjust their rifle’s scope settings. This can be done by shooting a group at 100 yards and then checking the point of impact. If the point of impact has shifted, the shooter can adjust the scope settings accordingly. A good rule of thumb is to make 1/4 MOA adjustments for every 10°F (5.5°C) change in temperature. For example, if the temperature drops by 50°F (10°C), the shooter would make a 2.5 MOA adjustment.

Techniques for Minimizing Zero Shift

Several techniques can be used to minimize zero shift in cold weather. One technique is to use a rifle with a heavy barrel, as this will reduce the amount of thermal expansion and contraction. Another technique is to use a scope with a “zero stop” feature, which allows the shooter to set a specific point of impact and prevent the scope from moving beyond that point. Finally, shooters can use a thermal compensation device, such as a temperature-compensating scope mount, to help minimize zero shift.