A. After firing the bore may be cleaned by using a sponge covered with burlap well saturated with water. The bore should then be permitted to drain and thoroughly dry before being oiled.
Q. If any rust has accumulated on a bearing part, would you use sandpaper to remove it?
A. The use of sandpaper is forbidden, and emery-cloth No. 1, being coarse enough for any ordinary rusting, should be used, the rust being softened if necessary by kerosene.
Q. Describe the recoil-cylinder for mortars and its action.
RECOIL CYLINDER FOR MORTARS.
Fig. 32.
A. Fig. 32. When the mortar is fired, the piston is forced down, causing the piston-head to force oil through the oil-holes shown on the left of Fig 32. This oil passes through the oil-cavity upward and in rear of the piston-head. By opening or closing these oil-passages by withdrawing or inserting different-sized plugs the friction, hence the recoil, can be adjusted.
Note.—For steel mortars model '91 the plugs are as in Fig. 32; that is, from top to bottom: closed, ½, 0, 0, ½, closed, closed. For C. I. mortars '91: c., ½, 0, 0, ¾, c., c. For model '96 c., ½, ¼, 0, ¼.