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

LEDE Marlin Dark
LEDE Marlin Dark

Hardware Review: Marlin Model 1895 Dark

If you think lever-action rifles should only have walnut stocks and a blued-metal finish, then the new Marlin Dark series with its polymer buttstock and aluminum AR-esque handguard probably won’t be your thing. That’s a shame, because this recent offering in Marlin’s line of modernized, capable lever-action rifles has a lot going for it in terms of performance, functionality and fun.

ATN Shipping TICO LTV Thermal Clip-On

This thermal clip-on device is a huge night-time gear multiplier for hunters and observers, transforming any daytime scope into a thermal sight.

MidwayUSA Named Official Sponsor of the 2025 NRA Annual Meetings

Glock, Inc. is the Presenting Sponsor of the Freedom Experience on Saturday, April 26th

First Look: Montana Rifle Company Marshall Hunting Rifle

Montana Rifle Company (MRC) has announced its Marshall Hunting Rifle—a rifle the company bills as being 10,000 rounds in the making.

Spring Gobbler Gear Roundup

Mike Roux lays out his winter's turkey gear discoveries, just in time for spring gobbler season.

National 4-H Shooting Sports Signs on as Official +ONE Partner

The National 4-H Shooting Sports program has joined the +ONE Movement, a national mentorship initiative led by the National Shooting Sports Foundation (NSSF) that encourages peer-to-peer mentorship in the hunting and shooting sports.

Interests



Get the best of American Hunter delivered to your inbox.