Doppler radar is used to accurately identify bullet velocity throughout travel downrange. Accurate BC values can then be calculated based on these known accurate bullet velocities at different known ranges. Accurate BC values can also be calculated based on bullet time-of-bullet-flight measurements collected over long yardages, either by light sensing chronographs of acoustic sensing chronographs. Good ballistics programs can use these accurate BC values to determine accurate dope for shots under variable and changing environmental conditions, locations, directions of fire, and slopes that can be encountered while hunting at any location, altitude, and conditions of fire. It's difficult and tedious to prepare for these variable and changing factors some hunters encounter by attempting to use printed range cards developed by measuring drops over extended distance at a practice range. Range cards are great for hunting at the same location where you collected the measured drops. But they won't be nearly as adaptable and accurate after relocating to a hunting location 500 miles away and 6000 feet higher in elevation, while engaging a game animal up or down a 25 degree sloped mountainside. Thus the advantage of a good ballistics program, loaded with an accurate BC value and muzzle velocity for the bullet in use.
Confirming corrective dope for the actual shot on game is a great tactic if a hunter is setting up to ambush game at a specific location. One can then set up a large target where the game is expected to appear and take practice shots until the rifle is zeroed dead-nutz on before the game animal walks over to the location where the target had been previously set up. On my hunts (mountainous terrain), I can't often predict when or where I'll be setting up for the shot. My ballistics program is able to provide accurate dope no matter where the shot presents, provided I've entered accurate data, including accurate BC values.
