Why does “klick” mean kilometer in US military slang?

Solution 1:

I was in the military, but not Viet-Nam era. From my own judgment, I don't think it has anything to do with odometers. I think it's a dark humor reference.

When sighting in an M-16, the sights are adjusted in clicks. Looking downrange at a calibrated 100 yard target, one click moves the projectile/impact one inch across the face of the target. (left/right/up/down)

In the same way, when looking at a topo map, one "klick" is one full increment line on the map.

So viewed from the sky, (the point of view of either God or an enemy bomber, however you wish to imagine it) when we go one kilometer, we've traveled one click across the face of the map. The unspoken implication is that in the end we all might just be points on someone else's target...

Simply my opinion, but that's how it struck me the first time I heard it.

Solution 2:

The term arose from the use of forward observed non-line of sight artillery targeting and actually began with the United States Marine Corp during the interwar period between the Korean and Vietnam wars. The M19 mortar introduced at the time had dials for adjusting the azimuth and elevation. It produced a loud "click" sound when both dials where set to a particular combination that resulted in a point of impact 1000m away on level ground at standard temperature pressure. It was during this period that Marines began developing the co-ordination of light artillery with infantry manuever by a forward observer using field radio.

Just as background, the M19 was actually introduced to the US Army in 1942, arriving in the Marine Corps. arsenal sometime later, as a replacement for the M2 mortar, but proved inferior in several respects. It was openly derided by many Marines and several jokes about it's inaccuracy involved jokes about it's "click" sound.

I was once told by an old gunner that the spelling 'klick' came from a field manual written by a german ex-pat associated with development of the weapon system. There may be some measure of truth to this, but the claim is somewhat dubious.

Solution 3:

Military grid reference system (MGRS) is metric, because it is used internationally within NATO. This may explain why US military use metric system for the distances on the ground. As for word itself, it is important for any military terms to be clearly distinguishable from the others on the radio. Kilometer can be easily confused with meter when radio is not very clear.

Solution 4:

A click was used as a reference on mortars, machine guns and some artillery early on in the military. The T&E mech. when moved 1 click would change the strike or impact 1 meter at a distance of 1000 meters. This info. found in the FM's on the above equipment.

One click or klick when talking about distance on a military map is 1000 meters or one km.

T&E-traverse and elevation

USMC-Vietman 67-68