It is 2½ feet shorter than the land version giving it a bore of only 54 inches (14.43 calibres), and hence a short stubby appearance.

The 15 cwt gun, identifiable by the raised coil in front of the vent slot, was intended for broadside use in sloops.

It has a bore of 84 inches (22.36 calibres) and hence has the appearance of a typical field gun.

After it became obsolete for regular Royal Artillery use, a small number were re-issued to Volunteer Artillery Batteries of Position from 1889, alongside 16-pounder RML guns and 40 Pounder RBL guns.

[6] The 1893 the War Office Mobilisation Scheme shows the allocation of twelve Artillery Volunteer position batteries equipped with 20 Pounder guns which would be concentrated in Epping, Essex in the event of mobilisation.