from The Century Dictionary and Cyclopedia
- n. A rifle throwing a very small bullet, especially used by sharp-shooters before the introduction of conical balls.
Sorry, no etymologies found.
It was equivalent to killing an elephant with a pea-rifle.
These men carried but one weapon: the long-barrelled, small-bored pea-rifle, whose bullets ran seventy to the pound, the amount of powder and lead being a little less than that contained in the cartridge of a thirty-two calibre Winchester.
-- American bushrangers advocate a long heavy pea-rifle, on the plea of its accurate shooting, and the enormous saving in weight of ammunition when bullets of a small size are used.
Kentucky rifle, which, from the ball being little larger than a pea, was called a pea-rifle.
No backwoodsman of Kentucky was ever more perfect in the use of his pea-rifle or more certain of his aim than was Annatock with his murderous whip.
 Captain Burton started with two huge elephant-guns, one double rifle, one pea-rifle, one air-gun, two revolving pistols, and a cross-bow, all of which he used for display to amuse the Arabs.