How quickly a four-inch gun crew fires 86 rounds

How long would a gun crew take to fire 86 rounds from a 4-inch/50 gun?

At a sustainable average near twelve rounds per minute, about seven minutes; a later 4-inch/45 sustaining roughly sixteen rounds per minute could do it in a little over five minutes.

The calculation avoids applying the gun's short-term maximum rate across the full ammunition expenditure. The older 4-inch/50 is estimated at a sustainable twelve rounds per minute. A later 4-inch/45 might sustain about sixteen. The comparison shows why prolonged engagements depend on sustained fire rather than a headline cyclic rate.