Webster's Revised Unabridged Dictionary · 1913

Galloper

Galloper , noun

1.
One who, or that which, gallops.
2.
(Military) A carriage on which very small guns were formerly mounted, the gun resting on the shafts, without a limber. — Farrow
Collocations (1)
Galloper gun , a light gun, supported on a galloper, -- formerly attached to British infantry regiments.