A brief history of cannon over the last thousand years

The first cannon
Gunpowder was first used in the UK around 1250 but it was not until fifty years later that the first cannon was used. They steadily increased in size in order to be able to fire larger projectiles and thus more damage to ever increasingly strong castle walls. Th famous Scottish gun, Mons Meg, dating from 1455 had a 13 foot long, 20 inch diameter barrel 1455. It had a range of 1000yards, but could only be fired at a rate of one shot per hour. The barrel got so hot it had to be allowed to cool to prevent an explosion.

By 1530 the standard army and naval cannons used 16 to 32 pound shots which they were able to fire up to a mile in range.

Nineteenth Century
In the early 1800's guns had improved so as to be able to fire a shot of up to 68 pounds a distance of 2500 yards at a rate of one shot per minute. The Napoleonic and Crimean Wars plus the threats of invasion in the mid 19th century and the development of iron clad ships spurred a massive development programme.

Rifled Muzzle Loading Gun
The first of two significant improvements was the rifled muzzle loading (RML) gun. This was still loaded down the barrel, but the grooved barrel allowed a higher velocity of shell. A range of ever larger RML guns were developed between the 1860s to 1880s:

• 7 inch barrel, range of 5500 yards at a rate of one every two minutes
• 12.5 inch barrel, 38 ton in weight, which fired an 800 pound shell a distance of 5500 yards (1200 yards was the most effective distance)
• 17.7 inch barrel, 100 tonnes in weight firing a 1 tonne shell a range of 3 miles. Installed at Gibralter & Malta

Breech Loading Gun
The other development was the use of rifled breech loading (BL) where the shell was introduced at the back of the gun rather than down the barrel. This allowed for much faster rates of fire and general improvements increased the range. Breech loading guns had been introduced in the 1850's but were unreliable with a tendency to explode unexpectedly. Towards the end of the 19th century these problems had been sorted and a wide range of BL guns were introduced.

• 6 inch gun, 5 tons in weight with a range of 7 miles, firing at 5 to 8 shells per minute
• 8 inch gun with a range of 15 miles
• 9.2 inch gun, 23 tons, range of 20 miles
• 13.5 inch gun, 69 ton in weight
• The largest was the 16 inch BL weighing 111 tons

By this time the defences of the south coast, the Palmerston Forts, were mainly redundant as a ship could stand off the coast a distance of 15 to 20 miles and rain shells down on the defenses. Most of the RML guns were removed and the forts were equipped with a much smaller number of BL guns.

Quick Firing Gun
In addition another new type of gun, Quick Firing, was introduced. These fired much smaller shells at 3 to 6 pounds, but had a range of 4 to 5 miles and could fire at 20 shells a minute which made them ideal for defending against enemy fast patrol boats.