The manually operated mounts could reach about ten rounds per minute with a good crew. Most crews lacked the training required to sustain that performance. Practice itself consumed barrel life, limiting the rounds available for learning the work. A rate of roughly seven or eight rounds per minute is given for crews with practice, while the same wear problem continued to restrict training.
Notable Point · 37:46-38:14
How barrel wear restricted gun-crew training
Rapid wear limited practice, making it harder for manually worked guns to achieve their best rate of fire.