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 M&P FPC In 10Mm
LEDE M&P FPC In 10Mm

First Look: Smith & Wesson M&P FPC in 10mm Auto

Smith & Wesson Brands, Inc. has released its M&P FPC chambered in 10mm Auto. This long-anticipated and even longer-requested, optics-ready 10mm FPC (Folding Pistol Carbine) utilizes a blowback design and is equipped with three, 15-round double-stack M&P M2.0 pistol magazines.

Field Tested: Nosler Whitetail Country

Renowned for its firearms, accessories, ammunition and bullets, Nosler recently broke with tradition and introduced an economical line of ammunition designed for deer hunters. How does it stack up? Read on.

First Look: Real Avid Smart-Torq Fixed Limiter Torque System

Real Avid has unveiled a new lineup of fixed torque limiters, the most precise and technically advanced torque limiters designed for serious DIY gun enthusiasts and professional gunsmiths alike.

Recipe: Creamed Venison and Peas

Brad Fenson creams together peas and venison in this wild-game take on a British classic.

Airport Conversation Leads to Wildlife-Related Charges

CDFW officers catch a pair of poachers after overhearing them on a plane.

NRA Files Lawsuit Challenging Colorado’s Excise Tax on Firearm and Ammunition Sales

On March 31, the National Rifle Association of America (NRA), together with the Firearms Policy Coalition, Second Amendment Foundation, Colorado State Shooting Association, Magnum Shooting Center and an NRA member, filed a lawsuit challenging Colorado’s 6.5-percent excise tax on the retail sale of firearms, firearm precursor parts and ammunition.



Get the best of American Hunter delivered to your inbox.