Complex sentence: During construction the armament was changed to ten Armstrong 110-pounder guns (an early rifled breech loader, or RBL), twenty-six 68-pounders, and four RBL Armstrong 40-pounder guns.
Split into simpler sentences: During construction the main armament was changed to ten Armstrong 110-pounder guns, an early rifled breech loader, or RBL, design. Secondary armament was twenty-six 68-pounders, and four RBL Armstrong 40-pounder guns.