(Chief Mechanic Only)
Caution.—Never remove piston rod nut, as piston is under pressure and would pull piston rod into cylinder.
The recoil apparatus proper cannot be dismounted.
If properly taken care of the recoil mechanism will not go wrong for years; but if neglected, its destruction is only a matter of very little firing.
The position of the gauge finger is the index as to whether or not the recoil is being properly absorbed.
The joints are not absolutely tight, the slight leakage which takes place during fire or even when gun is at rest is not important.
In normal firing conditions the recoil apparatus contains a slightly greater quantity of oil than absolutely necessary; this quantity is called the “reserve.” When the reserve is exhausted any loss is liable to reduce the quantity strictly necessary. The loss may prevent the gun from fully returning to battery when firing.
The amount of reserve is indicated by the position of the gauge.
No reserve: The gauge finger is down deep in its recess.
Full reserve: The end of the gauge finger is level with the gauge index.