August 24th, 2016

Sierra Test Reveals How Velocity Varies with Ammo Temperature

Sierra Bullets Ammunition Ammo temperature temp test hot F-Class Ammo cold
In this .308 Win test, 70° F ammo shot 96 FPS slower than ammo heated to 130.5° F. And the 130.5° ammo was 145 fps faster than ammo right out of the freezer (at 25.5° F). That’s a huge difference…

EDITOR’s NOTE: The Sierra tester does not reveal the brand of powder tested here. Some powders are much more temp sensitive than others. Accordingly, you cannot extrapolate test results from one propellant to another. Nonetheless, it is interesting to see the actual recorded velocity shift with ammo temperature variations in a .308 Win.

Written by Sierra Chief Ballistician Tommy Todd
This story originally appeared in the Sierra Bullets Blog
A few weeks ago I was attending the Missouri State F-Class Match. This was a two-day event during the summer and temperatures were hot one day and hotter the next. I shot next to a gentleman who was relatively new to the sport. He was shooting a basically factory rifle and was enjoying himself with the exception that his scores were not as good as he hoped they would be and he was experiencing pressure issues with his ammunition. I noticed that he was having to force the bolt open on a couple of rounds. During a break, I visited with him and offered a couple of suggestions which helped his situation somewhat and he was able to finish the match without major issues.

He was shooting factory ammunition, which is normally loaded to upper levels of allowable pressures. While this ammunition showed no problems during “normal” testing, it was definitely showing issues during a 20-round string of fire in the temperatures we were competing in. My first suggestion was that he keep his ammunition out of the direct sun and shade it as much as possible. My second suggestion was to not close the bolt on a cartridge until he was ready to fire. He had his ammo in the direct sunlight and was chambering a round while waiting on the target to be pulled and scored which can take from a few seconds to almost a minute sometimes.

This time frame allowed the bullet and powder to absorb chamber [heat] and build pressure/velocity above normal conditions. Making my recommended changes lowered the pressures enough for the rifle and cartridge to function normally.

Testing Effects of Ammunition Temperature on Velocity and POI
After thinking about this situation, I decided to perform a test in the Sierra Bullets underground range to see what temperature changes will do to a rifle/cartridge combination. I acquired thirty consecutive .30 caliber 175 grain MatchKing bullets #2275 right off one of our bullet assembly presses and loaded them into .308 Winchester ammunition. I utilized an unnamed powder manufacturer’s product that is appropriate for the .308 Winchester cartridge. This load is not at the maximum for this cartridge, but it gives consistent velocities and accuracy for testing.

I took ten of the cartridges and placed them in a freezer to condition.

Sierra Bullets Ammunition Ammo temperature temp test hot F-Class Ammo cold

Sierra Bullets Ammunition Ammo temperature temp test hot F-Class Ammo cold

I set ten of them on my loading bench, and since it was cool and cloudy the day I performed this test I utilized a floodlight and stand to simulate ammunition being heated in the sun.

Sierra Bullets Ammunition Ammo temperature temp test hot F-Class Ammo cold

I kept track of the temperatures of the three ammunition samples with a non-contact laser thermometer.

The rifle was fired at room temperature (70 degrees) with all three sets of ammunition. I fired this test at 200 yards out of a return-to-battery machine rest. The aiming point was a leveled line drawn on a sheet of paper. I fired one group with the scope aimed at the line and then moved the aiming point across the paper from left to right for the subsequent groups.

NOTE that the velocity increased as the temperature of the ammunition did.

The ammunition from the freezer shot at 2451 fps.

Frozen FPS

The room temperature ammunition shot at 2500 fps.

Room Temperature FPS

The heated ammunition shot at 2596 fps.

Sierra Bullets Ammunition Ammo temperature temp test hot cold

The tune window of the particular rifle is fairly wide as is shown by the accuracy of the three pressure/velocity levels and good accuracy was achieved across the board. However, notice the point of impact shift with the third group? There is enough shift at 200 yards to cause a miss if you were shooting a target or animal at longer ranges. While the pressure and velocities changed this load was far enough from maximum that perceived over pressure issues such as flattened primer, ejector marks on the case head, or sticky extraction did not appear. If you load to maximum and then subject your ammunition to this test your results will probably be magnified in comparison.

Sierra Bullets Ammunition Ammo temperature temp test hot cold

This test showed that pressures, velocities, and point-of-impact can be affected by temperatures of your ammunition at the time of firing. It’s really not a bad idea to test in the conditions that you plan on utilizing the ammo/firearm in if at all possible. It wouldn’t be a bad idea to also test to see what condition changes do to your particular gun and ammunition combination so that you can make allowances as needed. Any personal testing along these lines should be done with caution as some powder and cartridge combination could become unsafe with relatively small changes in conditions.

Permalink - Articles, Bullets, Brass, Ammo, Reloading 5 Comments »
August 24th, 2016

Remington History Featured on American Rifleman TV

Remington Arm Ammunition Television TV 200 Year

This week, American Rifleman TV looks at the history and heritage of Remington, which celebrates its 200th Anniversary this year. Founded in 1816, Remington is the oldest continuously-operating gun manufacturer in the United States, and it still sells more sporting rifles and shotguns than any other American company. Remington has also developed more cartridges than any other U.S. company. If you want to learn more about this important arms-maker, watch tonight’s episode, which you can preview below.

CLICK to Watch 200 Years of Remington Preview:

View past segments of American Rifleman TV at AmericanRifleman.org/artv, and tune into the Outdoor Channel Wednesday nights for the latest episodes.

Two Hundred Years of Gun-Making
Remington EliphaletRemington Arms Company celebrates its 200th year in business in 2016. The Remington enterprise was founded in 1816 by Eliphalet Remington in Ilion, New York, as E. Remington and Sons. Remington is America’s oldest gun maker and is still the largest U.S. producer of shotguns and rifles. And it is the only American Company that sells firearms and ammunition under its own name. CLICK HERE for 200 facts about the 200-year-old company.

American Life in 1816
What was life like in America in 1816, two hundred years ago? This infographic offers some interesting facts. For example, average life expectancy was only 39 years, and a farm laborer earned just $12-$15 per month. Still want to go back to the “good old days”?

Click to Zoom Infographic:
Remington 200 years

Permalink - Videos, Gunsmithing 1 Comment »
August 24th, 2016

Going Long in Norway — .338 Lapua Magnum Hits at 2165 Meters

Long Range Success with Lapua Scenars
With the interest in ultra-long-range shooting in the USA, we thought you might like to see how they shoot out past 2000 meters in Scandinavia. Recently, a new Norwegian long range record was shot in Sokndal in Norway, at the Bøstøl shooting range, using Lapua 300 grain Scenar bullets.

With the target at 2165 meters (1.345 miles), the shooters managed 2/10 hits on steel. The cartridge (as you might expect) was the powerful .338 Lapua Magnum. The load was 89 grains of Vihtavuori N570 pushing the 300gr Scenars at 815 ms (2674 fps). The firearm used was Accuracy International .338 LM AXMC rifle with 27″ barrel and suppressor. Before the record hits at 2165 meters, the team also engaged targets at 1639m, 1710m, and 1850m scoring 4/10 hits on 95 x 100 cm steel target (that’s roughly one meter square, just over 3 feet per side).

About the Location — Sokndal, Norway
Sokndal is the southernmost municipality in Rogaland county, Norway. It is located in the traditional district of Dalane. The administrative center of the municipality is the village of Hauge. Other villages in Sokndal include Li, Rekefjord, Sogndalsstranda, and Åna-Sira.

Permalink Bullets, Brass, Ammo, Tactical 3 Comments »