When the block is opened as far as it will go, it is locked in that position by the inside trunnions on the extractors. These trunnions are forced over horizontal shoulders on the block by means of the extractor plungers and holds the block in the open position. When a cartridge is pushed smartly into the gun, its rim striking against the lips on the extractor frees the trunnions from the shoulders on the block and allows the block to close under the action of the closing spring.

A continuous-pull firing mechanism is carried in the recess bored out in the center of the block and is operated by the trigger shaft which projects from the bottom of the block. This mechanism is cocked and fired by one continuous motion of the trigger shaft so that in case of a misfire the primer may be struck a second blow by releasing the shaft and rotating it again. A lanyard may be attached to the projecting end of the trigger shaft.

CARRIAGE.

Weights and Dimensions.
Weight of carriage, complete, fully equipped, without the gun2280 pounds
Weight of gun and carriage fully equipped3045 pounds
Weight of lunette, carriage limbered140 pounds
Diameter of wheels56 inches
Width of track, center to center of wheels60 inches
Length of recoil of gun on carriage, variable recoil18 to 46
Height of axis of gun about ground42 approx.
Amount of elevation with elevating handwheel42 degrees
Total limits of elevation7 to plus 53 degrees
Maximum traverse either side of center400 mils
Over all width of trails, spread130 inches
Over all length, muzzle of gun to end of lunette173 inches
Limits of elevation with angle of site handwheel, minus 7 degrees depression to 11 degrees elevation.

Description.

The carriage is of the split trail, variable long-recoil type. The length of recoil is regulated automatically, so that the breech of the gun will not strike the ground on recoil at an angle of elevation of less than 47 degrees. At elevations greater than 47° a hole must be dug for the breech in recoil.

The gun is mounted in slides on a cradle formed by the spring cylinder. The spring cylinder is suspended by trunnions mounted in bearings in the top carriage, which is supported by the pintle bearing to which are attached axle arms bearing in the wheels.

The carriage has an independent angle of site elevating mechanism, by means of which a maximum depression of seven degrees and an angle of elevation of 11 degrees may be obtained. The remaining elevation is obtained through the elevating handwheel.