How Much Does Temperature Effect Bullet Impact?

by
posted on June 28, 2013
bs_2015_fs.jpg (8)

The Background
I got an email from a reader who was looking to order a CDS dial from Leupold, which requires certain information (including altitude, temperature, etc.).  He was concerned about what temperature to provide them. What if his dial said 80 degrees Fahrenheit and he was hunting in 40-degree weather?

The Question
What effect does temperature have on a bullet’s impact at reasonable hunting distances?

The Data
We’ll take a fairly common hunting round, the .270 Winchester with a 130 gr. TTSX bullet. The Barnes Vor-Tx factory load advertises a muzzle velocity of 3060 fps.  Using the Hornady Ballistics Calculator, we will set the altitude, barometric pressure, and humidity at a constant (Sea Level, 29.53 hg, 78 percent) and adjust temperature to determine the variance.

Bullet drop

Distance (yards):        200      300      400      500

100 Deg F                   2.8”     10.7”   24.6”   45.4”

80   Deg F                   2.9”     10.9”   25”      46.3”

30   Deg F                   3”        11.2”   26”      48.6”

0     Deg F                   3”        11.5”   26.7”   50.3”

The Results
As you can see from the numbers, temperature has a minimal effect on bullet drop at reasonable hunting distances. All things being equal, bullets will drop more at lower temperatures, but the difference is negligible. (Note: Changes in temperature are often accompanied by changes in humidity and pressure that can give you different results)

The Ruling
Temperature is a non-factor for 98 percent of shots in big-game hunting. Even with a temperature swing of 50 degrees, the difference in point-of-impact is only an inch at 400 yards. I don’t know about you, but I can’t hold an inch at 400 yards under hunting conditions. If you’re ordering a custom dial, use a reasonable “average” temperature for the locales where you’ll be hunting and put it out of your head.

Latest

2022 GBA AOTY Winchester 6.8 Western Lead
2022 GBA AOTY Winchester 6.8 Western Lead

2022 Ammo of the Year: Winchester 6.8 Western

Any way you cut it, this cartridge is a long-range winner. It maintains its energy at distance, and it’s plenty accurate, too.

Pioneering Wild Turkey Research Underway

The National Wild Turkey Federation (NWTF) is helping fund a new wild-turkey research project conducted by Mississippi State University and the Mississippi Department of Wildlife, Fisheries and Parks.

2022 Optic of the Year: ATN ThOR 4 Thermal Riflescope

ATN Corp. sits at the cutting edge of consumer-based thermal technology, and its ThOR 4 Series 640x480 2.5-25x50mm is the best such riflescope it offers.

Federal Ammunition Raises $218,000 for Local Organizations

In celebration of Federal’s 100th Anniversary, Federal will be donating more than $218,000 dollars to local organizations in support of their critical missions.

Federal Duck Stamps for 2022-23 Season on Sale

The 2022-23 Federal Duck Stamp goes on sale Friday, June 24. The stamps, which cost $25 and raise about $40 million for conservation each year, are valid from July 1, 2022, through June 30, 2023.

2022 Muzzleloader of the Year: CVA Paramount HTR .40-Caliber

With its hunting-style stock, adjustable comb and premium Bergara barrel, the .40-caliber CVA Paramount HTR is capable of producing centerfire velocities previously thought unattainable from a muzzleloader.

Interests



Get the best of American Hunter delivered to your inbox.