 In the flank barbettes are mounted two mark III RML 64 pounder 64 cwt guns , numbers 462 and 463 . They are rifled muzzle @-@ loading heavy guns weighing 64 long hundredweight ( 3 @,@ 300 kg ) with a 6 @.@ 3 @-@ inch ( 160 mm ) calibre steel barrel . They were made to the model 's 1867 pattern by the Royal Arsenal , Woolwich , England in 1872 . Their intended use was to protect the flanks and approaches to the fort . These smaller guns use an 8 lb ( 4 kg ) charge of gunpowder to send a 64 lb ( 29 kg ) projectile up to 5 @,@ 000 yards ( 4 @,@ 600 m ) . There are iron rings fixed in the rampart wall that indicate traversing gun carriages were intended to be mounted , though this never eventuated . The guns were supplied with siege over @-@ bank carriages . The lower carriage sections are the type made for the guns when used as field pieces and the upper sections are brackets that raise the guns to the over @-@ bank firing position . In this particular configuration the two guns are thought to be the last in the world . 
 In the flank barbettes are mounted two mark III RML 64 pounder 64 cwt guns , numbers 462 and 463 . They are rifled muzzle @-@ loading heavy guns weighing 64 long hundredweight ( 3 @,@ 300 kg ) with a 6 @.@ 3 @-@ inch ( 160 mm ) calibre steel barrel . They <a href='uninflect' title='1'><mark>were</mark></a> made to the model <a href='null_genetive' title='2'><mark>'s</mark></a>1867 pattern by the Royal Arsenal , Woolwich , England in 1872 . Their intended use was to protect the flanks and <a href='uninflect' title='3'><mark>approaches</mark></a> to the fort . These smaller guns use an 8 lb ( 4 kg ) charge of gunpowder to send a 64 lb ( 29 kg )<a href='been_done' title='4'><mark></mark></a> <a href='uninflect' title='5'><mark>projectile</mark></a> up to 5 @,@ 000 yards ( 4 @,@ 600 m ) . <a href='dey_it' title='6'><mark>There</mark></a> are iron rings fixed in the rampart wall <a href='null_relcl' title='7'><mark>that</mark></a>indicate traversing gun carriages <a href='uninflect' title='8'><mark>were</mark></a> intended to be mounted , though this never eventuated . The guns <a href='uninflect' title='9'><mark>were</mark></a> supplied with siege over @-@ bank carriages . The lower carriage sections <a href='drop_aux' title='10'><mark>are</mark></a>the type made for the guns when used as field pieces and the upper sections <a href='drop_aux' title='11'><mark>are</mark></a>brackets <a href='null_relcl' title='12'><mark>that</mark></a>raise the guns to the over @-@ bank firing position . In this particular configuration the two guns are thought to be the last in the world . 
In da flank barbettes r mounted two mark III RML 64 pounder 64 cwt guns , numbers 462 and 463 . They arrifled muzzle @-@ loading heavy guns weighing 64 long hundredweight ( 3 @,@ 300 kg ) with a 6 @.@ 3 @-@ inch ( 160 mm ) calibre steel barrel . They was made to the model  1867 pattern by the Royal Arsenal , Woolwich , England in 1872 . Their intended use was to protect tdaflanks and approach to the fort . These smaller guns use an 8 lb ( 4 kg ) charge of gunpowder to send a 64 lb ( 29 kg ) been projectiled up to 5 @,@ 000 yards ( 4 @,@ 600 m ) . It is iron rings fixed in thdaampart wall indicate traversing gun carriages was intended to be mounted , tho this never eventuated . The guns was supplied witt siege ova @-@ bank carriages . The lower carriage sections thedape made for the guns when used as field pieces and the upper sections brackets raise the guns to the over @-@ bank firing position . In this particular configuration the da guns are thought to be the last in the world .