Scale: Unknown. Wooden model of a gun carriage mounted on four brass wheels. An aperture slightly forward of the centre of the carriage acts as a pivot. The wheels are permanently fixed at an angle which scribe an arc around the pivoting point of the carriage. The surface of the carriage has a rail running along its length to enable a gun to slide back and forth, retracting it as necessary. The carriage is inclined to the front at an angle of about 20 degrees, thus the front wheels are mounted on tall legs while the rear wheels are mounted directly to the underneath of the carriage.