Cannon skills: Shoot and Rapid Reload

[abarbieriPotC]

Hi,

from the player's guide:

• Shoot: Combat Basic Cannoneering Skill –– upgrade to increase Cannon firing rate

• Rapid Reload: Passive Increases Cannon reloading speed

what is exactly the difference between these skills?

because they both seem to reduce the time between sets of shots are available (round shot 3, chain shot 2, Thunderbolt 1, etc)

or 'Rapid Reload' helps when switching between ammo types and 'Shoot' when using the same ammo type?

thanks