Mk V 4inch gun

The 4″/45 MK Vs were the standard high-angle DP guns of the Royal Navy in the 1930s. With a rate of fire that went to 10-15 rounds per minute depending on the training of the gun crew, they could fire a 53.5-pound HE shell to an anti-aircraft ceiling of 31,000 feet or a 56-pound SAP shell against a surface target to 16,430 yards. Historic Naval Ships Association image.