What made a naval gun quick-firing?

What is the difference between a quick-firing naval gun and a non-QF gun?

QF guns used cartridge-cased ammunition, often as a fixed round, to reduce separate handling and speed loading.

Quick-firing depended on ammunition design and handling. Smaller QF weapons commonly used a cartridge case and often a fixed round, allowing the projectile and propellant to be moved and loaded together. Larger non-QF guns more often required the shell and propellant charge to be handled separately. The practical payoff was a faster loading cycle rather than a claim that every QF weapon achieved the same rate of fire.