 During the mid @-@ 1930s reconstruction the torpedo tubes were removed and the Vickers two @-@ pounders were replaced by twenty license @-@ built <unk> 25 mm Type 96 light AA guns in 10 twin @-@ gun mounts . This was the standard Japanese light AA gun during World War II , but it suffered from severe design shortcomings that rendered it a largely ineffective weapon . According to historian Mark <unk> , the twin and triple mounts " lacked sufficient speed in train or elevation ; the gun sights were unable to handle fast targets ; the gun exhibited excessive vibration ; the magazine was too small , and , finally , the gun produced excessive muzzle blast " . These 25 @-@ millimetre ( 0 @.@ 98 in ) guns had an effective range of 1 @,@ 500 – 3 @,@ 000 metres ( 1 @,@ 600 – 3 @,@ 300 yd ) , and an effective ceiling of 5 @,@ 500 metres ( 18 @,@ 000 ft ) at an elevation of 85 degrees . The maximum effective rate of fire was only between 110 and 120 rounds per minute because of the frequent need to change the fifteen @-@ round magazines . In addition the forward pair of 14 cm guns in the forecastle were removed at this time and the maximum elevation of the remaining guns was increased to + 30 degrees . 
