What is "gaining twist"

Gain \Gain\, v. i. To have or receive advantage or profit; to acquire gain; to grow rich; to advance in interest, health, or happiness; to make progress; as, the sick man gains daily. Thou hast greedily gained of thy neighbors by extortion. --Ezek. xxii. 12. Gaining twist, in rifled firearms, a twist of the grooves, which increases regularly from the breech to the muzzle. To gain on or To gain upon.

1. To encroach on; as, the ocean gains on the land.

2. To obtain influence with.

3. To win ground upon; to move faster than, as in a race or contest.

4. To get the better of; to have the advantage of.

   The English have not only gained upon the Venetians in the Levant, but have their cloth in Venice itself.
   --Addison.

   My good behavior had so far gained on the emperor, that I began to conceive hopes of liberty.
   --Swift.

Twist \Twist\, n.

1. The act of twisting; a contortion; a flexure; a convolution; a bending.

   Not the least turn or twist in the fibers of any one animal which does not render them more proper for that particular animal's way of life than any other cast or texture.
   --Addison.

2. The form given in twisting.

   [He] shrunk at first sight of it; he found fault with the length, the thickness, and the twist.
   --Arbuthnot.

3. That which is formed by twisting, convoluting, or uniting parts. Specifically:

   1. A cord, thread, or anything flexible, formed by winding strands or separate things round each other.

   2. A kind of closely twisted, strong sewing silk, used by tailors, saddlers, and the like.

   3. A kind of cotton yarn, of several varieties.

   4. A roll of twisted dough, baked.

   5. A little twisted roll of tobacco.

   6. (Weaving) One of the threads of a warp, -- usually more tightly twisted than the filling.

   7. (Firearms) A material for gun barrels, consisting of iron and steel twisted and welded together; as, Damascus twist.

   8. (Firearms & Ord.) The spiral course of the rifling of a gun barrel or a cannon.

   9. A beverage made of brandy and gin. [Slang]

4. [OE.; -- so called as being a two-forked branch. See Twist, v. t.] A twig. [Obs.]
   --Chaucer. Fairfax.

5. Act of imparting a turning or twisting motion, as to a pitched ball; also, the motion thus imparted; as, the twist of a billiard ball.

6. A strong individual tendency, or bent; a marked inclination; a bias; -- often implying a peculiar or unusual tendency; as, a twist toward fanaticism.

   Gain twist, or Gaining twist (Firearms), twist of which the pitch is less, and the inclination greater, at the muzzle than at the breech.

   Twist drill, a drill the body of which is twisted like that of an auger. See Illust. of Drill.

   Uniform twist (Firearms), a twist of which the spiral course has an equal pitch throughout.

n. In rifled firearms, a twist of the grooves, which increases regularly from the breech to the muzzle.