Courtesy of Breach Bang Clear

Language Lessons: TRACE

by David “Norseman” Williams

cover photo from the Forensic Outreach Library

TERM: Trace

ALSO KNOWN AS: ghost trail, vapor trail, gas trail, frost trail, shock wave

RELATES TO:  Exterior ballistics, spotting and shot placement (calling shots).

APPLICATION OF USE: Most handy in an environment when bullet impacts cannot be easily observed, such as long range hunting and target shooting applications.Watching the trace of a round can help a shooter adjust the placement of subsequent rounds.

DEFINITION:  Trace is the visible displacement of air by a projectile as it flies through the air. The phenomenon allows you to visually follow the passage of a bullet in flight. (In extremely simple terms, remember the distortion caused by the passage of bullets in the Matrix movies?

(from the noun)
1. a surviving mark, sign, or evidence of the former existence, influence, or action of some agent or event; vestige: traces of an advanced civilization among the ruins.
2. a barely discernible indication or evidence of some quantity, quality, characteristic, expression, etc.: a trace of anger in his tone.

WHY IT MATTERS: Only hits count, and bullets are expensive. Plus, nothing gets chicks hotter at Nancy’s Squat and Gobble than a ballistician discussing projectile trajectory and associated atmospheric phenomenon.

INTO THE WEEDS: The aka terms listed above are not technically synonymous with each other, but they’re frequently used interchangeably. The effect of a bullet in the air is (very) roughly analogous to the wake of a boat through the water. The disturbance created by the bullet’s passage causes a concurrent distortion of light. It is similar in appearance to the shimmer/haze effect you might see radiating off a hot highway in the distance.

It is difficult for some shooters to pick up trace, at least initially. Any object as small as a bullet, even a big bullet, is moving quickly (and even slow bullets are fast).


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