Each rifled muzzle loader gun could fire a 400-pound shell through ten inches of ship armour at 1,000 yards.

But the guns could only fire one round every three minutes, which was fine against slow-moving, wooden sail ships but poor against fast-moving armoured steam ships.

By the 1890s, rifled muzzle loaders were replaced by new steel breach-loading guns, but Fort St. Catherine wasn't rearmed with the new weaponry, mostly because of the fort's geographical exposure. The fort was eventually abandoned in favour of Alexandria Battery and Fort Victoria.

It is unknown when the guns were thrown out of the fort – allegedly abandoned as useless – but it was either at the turn of the century or as late as the Second World War when Fort St. Catherine was used by US forces as a submarine listening post.

Three of the five guns landed on the beach, one in the water and one near Achilles Bay where they sat until they were removed last week.

Rifled muzzle loaders represent an interesting period in the development of artillery.

Bermuda was armed with 23, almost ten percent of the 250 that were ever made.