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Long Range Shooting; Wind Mirage, Coriolis Effect & Other Factors Affecting Bullet Calculator

The longest confirmed kill was by an unnamed Canadian sniper of the Joint Task Force 2 in May 2017 over a distance of 3,540 m (3,871 yards or 2.199 miles. He used a McMillan Tac-50 shooting the 12.7 x 99 Browning 50 caliber cartridge with a Hornady A-Max .510” diameter 750 grain bullet. That’s out there. Using the Hornady Ballistic Calculator (nobody else could handle 50 caliber) we come up with the following, as the calculator only reaches out to 2000 yards, a little over halfway. The bullet would take 2.88 seconds to cover the first 2000 yards. This is considered the transonic region for the Browning. The Hornady A-Max may stretch this out, but at over 3800 yards the bullet had to have been subsonic. The transonic region is between Mach 1.2 – .8 and the pressure center moves forwards at this velocity approaching the tip. Many bullets destabilize and tumble. Hornady’s calculator shows the bullet was moving at only 1343 fps, sonic the speed of sound is about 1125 fps. Given another 1871 yards the bullet had to have been subsonic.

Coriolis Effect Bullet Calculator

Coriolis Effect. Over these distances the Earth’s rotation affects the bullet. Shoot east you hit high. Shoot west you hit low. North and south, well wow, it’s tough. Angles to the north our south would affect the bullets travel. Time to 2000 yards is calculated at 2.89 seconds, given a 2800 fps muzzle velocity. To 3871 yards the time could be over 4 seconds, that is a long time to be subject to the wind. Over that distance there will be multiple wind conditions, gusts, rotational winds other things.

Wind Mirage Effect

Mirage effect was probably very magnified at distance. Mirage is caused by rising heat waves, over two miles the bullet is going to traverse multiple mirage generating geological formations. Wind affects the mirage. Bullet drop at 2000 yards is 1403 inches, that is close to 117 feet, was the shooting using the International Space Station to judge his trajectory? The drop would be much higher when the bullet met target. Estimating the range alone would be difficult, range finders don’t see out that far. Kill shots made at 2400 yards were behind berms, downward angle of the projectile is so high and steep it cleared intervening terrain features. The scope adjustments would most likely not accommodate that range at over 2 miles, so the shooter had to use considerable Kentucky elevation or hold over, he had to guesstimate it.

Other Factors Affecting Bullet Travel

Other factors would include humidity, probably dry but temperature and barometric pressure will affect bullet travel over that distance. Spin drift would be factor over extended ranges. Because the way air flows across and affects the bullet, a right-hand spin caused drift to the right, while left hand twist goes to the left. Spin drift for the 308 Sierra 175 grain Matchking at 2600 fps muzzle velocity in a 1:12 twist rate will drift in quiet air 11.57 inches, almost a foot at 1000 yards.

Custom Portable Modular Shooting Ranges

Not to diminish the skill of the shooter it is obvious that a lot of luck was involved after pulling the trigger, this feat given all the variables only touched on here may never be duplicated, let alone surpassed. Shooting Range Industries offers custom shooting ranges. Contact us for more information.

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