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

Herman Shooting Patriot LRT
Herman Shooting Patriot LRT

#SundayGunday: Mossberg Patriot LRT

Get a closer look at the Mossberg Patriot LRT, the latest addition to our #SundayGunday series.

Crossing Back Into Bowhunting

A bowhunt with any bow is still a hunt, same as it was many years ago. An inability to pull back a vertical bow will teach you that.

5 Black Friday Sales for Hunters

Its about that time of year again. Christmas is around the corner, and many shoppers are poised to get a jump on their holiday purchases this upcoming Friday. If you have a hunter on your list, here are five sales to consider from across the hunting marketplace.

Field Care for Good Venison

Mike Roux shares his tips and tricks for caring for venison from field to table.

First Look: HEVI-Shot HEVI-Hammer Waterfowl Ammo

HEVI-Shot adds a new load to its HEVI-Hammer Waterfowl shotshell lineup. 

Behind the Bullet: 350 Legend

The 350 Legend is designed specifically for hunters to deliver massive downrange energy transfer with improved penetration from a modern straight-walled cartridge.

Interests



Get the best of American Hunter delivered to your inbox.