Crack / Thump Method: The speed of sound is approximately 340 m/s at ATD ATM while the bullets velocity typically starts off 2 to 3 times faster than this. This results is a sound delay ("crack-bang") between the two's arrival at the target. The enemy's supersonic bullets produce a sonic boom, creating a "crack" sound as they pass by. The idea is, that if the enemy bullet's TOF is known, his range can be roughly estimated by measuring the delay between the bullet's passing and the sound of the rifle shot, and then compared it to a table of values. However, this is only relatively effective out to 500 meters; beyond this, the delay starts to stabilize and then drop back down to zero and eventually reverse. This all happens differently depending on your cartridge, load, and atmospheric conditions.
FM 23-10 Distance to firer: "The time difference between the crack and the thump can be converted into an approximate range. A one-second lapse between the two is about 600 yards with most calibers; a one-half-second lapse is about 300 yards." Is this helpful? Watch this video to see!
Sorry for the crazy audio shifts - this was rendering attempt #3 and Rex almost threw his computer out the window into the pond... lol -must be that old 'reptile nature' coming through again. If anyone knows the special prayer for computer video rendering, please say it...
Song Title: Wadi Watir
Music and Lyrics by: TiborasaurusRex
Instrumentation and Vocals by: TiborasaurusRex
Recorded by: TiborasaurusRex
