Firing, Precautions and Preparations for.
Before firing, inspect to see that cylinders are properly closed and that the cylinder end stud nut and piston rod-nut are in place. If time permits, oil slides before firing. Note length of recoil for the first few shots to be sure that the recoil mechanism is working properly. There is no danger as long as the recoil does not exceed 48 inches. Therefore, for first shot always set recoil indicator for about 42 inches. If the gun fails to return fully into battery, it is probably due (1) to dirt on slides and guides, (2) to cutting of slide surfaces on account of lack of oil, (3) to gland being screwed up too tightly, (4) to dirt or foreign particles in the cylinder, and especially in the counter recoil buffer recess, (5) to weakness of springs, 90% of such cases will be found to be due to 1, 2 or 3. Lock the cradle to the trail at drill and at traveling to avoid unnecessary strain upon the pointing mechanism. After unlimbering, release elevating and traversing lock before attempting to elevate or traverse gun.