The lodgment of the shot,—a compression of the metal on the lower side of the bore, at the seat of the shot, which is caused by the pressure of the gas in escaping over the top of the shot. There is a corresponding burr in front of the lodgment; and the motion thereby given to the shot causes it to strike alternately on the top and bottom of the bore, producing other enlargements, generally three in number: the first, on the upper side a little in advance of the trunnions; the second, on the lower side about the astragal; the third, in the upper part of the muzzle; it is chiefly from this cause that brass guns become unserviceable. Scratches, caused by the fragments of a broken shot, or the roughness of an imperfect one; enlargement of the muzzle by the striking of the shot in leaving the bore; external cracks, or longitudinal slits, caused by too great a compression of the metal on the inside.
64. When is a piece said to be honeycombed?
When the surface of the bore is full of small holes or cavities.
65. To what is this due?
To the melting and volatilization of a portion of the tin in the alloy; tin being much more fusible than copper.
66. Do lodgments cause an inaccuracy of fire?
They do.
67. How may this in a measure be remedied?
By using a wad over the cartridge, in order to change the place of the shot; or by wrapping the shot in woollen cloth or paper, so as to diminish the windage. In field guns, the paper cap which is taken off the cartridge should always be put over the shot.
68. To what injuries are iron cannon subject?