from
The Collaborative International Dictionary of English v.0.48
Rapid-fire \Rap"id-fire`\, Rapid-firing \Rap"id-fir`ing\, a.
(a) (Gun.) Firing shots in rapid succession.
(b) (Ordnance) Capable of being fired rapidly; -- applied to
single-barreled guns of greater caliber than small arms,
mounted so as to be quickly trained and elevated, with a
quick-acting breech mechanism operated by a single motion
of a crank or lever (abbr. R. F.); specif.: (1) In the
United States navy, designating such a gun using fixed
ammunition or metallic cartridge cases; -- distinguished
from breech-loading (abbr. B. L.), applied to all guns
loading with the charge in bags, and formerly from
quick-fire. Rapid-fire guns in the navy also sometimes
include automatic or semiautomatic rapid-fire guns; the
former being automatic guns of not less than one inch
caliber, firing a shell of not less than one pound
weight, the explosion of each cartridge operating the
mechanism for ejecting the empty shell, loading, and
firing the next shot, the latter being guns that require
one operation of the hand at each discharge, to load the
gun. (2) In the United States army, designating such a
gun, whether using fixed or separate ammunition, designed
chiefly for use in coast batteries against torpedo
vessels and the lightly armored batteries or other war
vessels and for the protection of defensive mine fields;
-- not distinguished from quick-fire. (3) In Great
Britain and Europe used, rarely, as synonymous with
{quick-fire}.
[Webster 1913 Suppl.]