It snowed 12 inches the week before and a warming spell created a crust on the snow, making walking difficult and noisy. An hour from camp our hunter spies a great buck in the distance. Our hunter crouches low in the sage and walks to the side of a small hill, gaining a slight elevation advantage and better shooting position for the shot. Itís 17 degrees outside as he struggles with numb hands to free his range finder from his coat pocket. Shivering from the cold and the excitement of seeing a world class buck, he zaps the laser rangefinder and it fails.
His warm breath condenses on the eye piece and freezes. Twice more it flatlines, and finally on the fourth attempt he gets a reading. The bold red numbers read 775 YARDS. Heís confident he can make the shot. Heís seen it done on TV many times. He recalls the success stories of fellow hunters at the gun club who have taken game at greater distances. He checks his data chart and dials the correction. At 775 yards the bullet will drop 123 inches, the hill is protecting the hunter from the 3-5 mph breeze that is blowing, the 12 inches of snow has covered the bunch grass and the stiff sage brush offers no indication as to wind velocity or direction. Focusing on the deer, our hunter does his best to provide the perfect trigger squeeze under the frigid temperatures.
Letís examine a few of the environmental hazards involved in the above shot.
1) Never rely on a single reading from the laser rangefinder when it has flatlined several times before. We MUST get consistent readings to confirm an accurate range to the target. The error factor is too great to risk the shot of a lifetime. A mere 25 yard change in the distance to the deer can result in an 11 inch point of impact change.
2) Our shooter has loaded his ammunition with R/L #22, not the best powder choice when it comes to temperature sensitivity. With a 53 degree change in temperature from his chronograph testing at 70 degrees he may well experience a 100 fps loss in velocity or MORE. With a 100 fps loss in velocity the bullet will drop an additional 9.75 inches.
3) The unnoticed left to right breeze of just 3-5 mph will cause a 14-15 inch deflection in our bulletís flight. Keep in mind that it is very difficult to accurately gauge the wind beyond the shooter especially over broken/irregular ground with hills and timber. A full value 10 mph wind will deflect the bullet 38.44 inches under the above conditions.
4) Add in a little flinch, imperfect trigger squeeze, or the rifle shifting under recoil from the less than perfect shooting position over the pack, and who knows where the bullet may strike?
The chances of our hunter connecting with the buck are pretty slim in my opinion. Wouldnít you agree?
Letís stretch the barrel a bit more and make the mythical 1000 yard shot under the same conditions.
At 3000 fps bullet drop is 249.84 inches, at 2900 fps (remember the 100 fps loss from our temperature change) drop is 269.87 inches--a 20 inch difference! Wind drift in a full value 3-5 mph wind is 26-27 inches, provided we have a consistent wind ALL THE WAY TO THE TARGET. Miss the target distance by 25 yards, add 18 plus inches to the drop.
These are point of impact changes with just a 100 fps change in velocity and a 3-5 mph breeze. Experience a 1.5 point change in barometric pressure and drop at a 1000 yds. increases to 279 inches. Hmm, are we starting to see the severity of changing and unpredictable conditions at long range? Cogitate on a 600 yd. uphill 20 degree shot, with a 7:30-1:30 quartering wind at 10 mph. Does bullet lift come to mind? If so, how much?
Ask competitive long range shooters how often they hit the X-ring with the first shot in competition? ďNot very often,Ē should be the reply! Keep in mind they are shooting at an EXACT 600-800 and 1000 yds. with wind flags from a very stable position with very little adrenaline/excitement flowing in their veins.