"Defence" was rearmed during her 1867–1868 refit with fourteen 7-inch and two rifled muzzle-loading guns. The new guns were heavier so fewer could be carried. The shell of the 15-calibre 8-inch gun weighed while the gun itself weighed . It had a muzzle velocity of and was credited with the ability to penetrate a nominal of wrought iron armour at the muzzle. The 16-calibre 7-inch gun weighed and fired a shell. It was credited with the nominal ability to penetrate armour.