Does this Feat allow move-equivalent reloading for all heavy crossbows (heavy/repeating/great Xbow) that normally take a full-round action to reload, or just to the "Heavy Crossbow" per se?
Rapid Reload is good for all types of crossbows. For repeating crossbows, it assume you have spare cartridge filled with bolts. If not, then you're going to spend some more time refilling the cartridge on your repeating crossbow.