The chamber was of the "Gomer" conical pattern, tapering towards the rear, typical of mortars of the day.

This was necessitated by the need to minimise the gun's weight while still allowing it to fire a relatively heavy shell : it ensured that the thickest amount of metal surrounded the point of maximum pressure on firing, at the rear of the chamber.

However, mortars fired at high elevations, allowing the powder charge to naturally seat into the coned rear end of the chamber, whereas guns such as this fired on a relatively flat trajectory, leading to the powder charge sitting on the bottom of the chamber.

Hence in sea service using smaller "reduced" charges such as in short-range actions this slowed the rate of fire as precautions had to be taken to ensure that the powder charge remained correctly positioned within the chamber until firing, to avoid a misfire.

[9] The early 6.71 ft (205 cm) 50 cwt version was deemed "too light and short for armament of great ships of war" and the 9 ft (270 cm) 65 cwt version of 1838 was the model typically deployed on British warships "of all rates and classes".