Line (length)

The line is an archaic pre-metric and pre-decimal unit of measurement, one line being equal to 1/10 or in some cases 1/12 of an inch.

In use

The line was most useful in machining and became a standard to which small arms ammunition was manufactured. A 7.62 mm caliber round seems a numerically arbitrary round, until it is realised that 7.62 mm is 0.3 inches, .30 cal or three-lines. The Russian Mosin-Nagant rifle for example is known as the "Three-line rifle". There was also the "Four-line" Swedish 12.17 x 44 mm round, although rarely referred to as such the 12.7mm Browning HMG round is a "Five-line" round. The actual calibre of the round would differ as the actual value of the inch would vary from country to country.

References

*Military small arms of the 20th Century, 6th edition, Ian V Hogg and John Weeks, Guild Publishing, 1991.

ee also

* Imperial unit
* Ligne
* Obsolete Russian units of measurement