Page:Miscellaneous Papers on Mechanical Subjects.djvu/90

 so much friction as to impede the progress of the ball to an injurious, and sometimes dangerous degree, and to produce loss of elevation and range; but my experiments show the contrary to be the case. The effect of too quick a turn, as to friction, is felt in the greatest degree when the projectile has attained its highest velocity in the barrel, that is at the muzzle, and is felt in its least degree when the projectile is beginning to move, at the breech. The great strain put upon a gun at the instant of explosion is due, not to the resistance of friction, but to the vis inertiæ of the projectile which has to be overcome. In a long barrel, with an extremely quick turn, the resistance offered to the progress of the projectile as it is urged forward becomes very great at the muzzle, and although moderate charges give good results, the rifle will not respond to increased charges by giving better elevation. If the barrel be cut shorter an increase of charge then improves the elevation.

The use of an increasing or varying turn is obviously injurious, for besides altering the shape of the bullet it causes increased resistance at the muzzle,—the very place where relief is wanted.

Finding that all difficulty arising from length of projectiles is overcome by giving