text:  From 1875 onwards , the balance between <unk> and muzzle @-@ loading changed . Captain de <unk> invented a method of reliably sealing a breech , adopted by the French in 1873 . Just as <unk> , the growing size of naval guns made muzzle @-@ loading much more complicated . With guns of such size there was no prospect of <unk> in the gun for re @-@ loading , or even re @-@ loading by hand , and complicated hydraulic systems were required for re @-@ loading the gun outside the turret without exposing the crew to enemy fire . In 1882 , the 81 @-@ ton , 16 @-@ inch ( 406 mm ) guns of HMS <unk> fired only once every 11 minutes while bombarding Alexandria during the <unk> <unk> . The 100 @-@ ton , 450 mm ( 17 @.@ 72 inch ) guns of <unk> <unk> could each fire a round every 15 minutes . 
  