Erudite as ever, it is Gough Thomas who I think covers this well. He says that 'some guns are self-openers before they are fired, but not after. These are not true self-openers. The distinction rests on whether, when both barrels have been discharged, the force of the mainspring (as in the Purdey/Beesley action) or of some auxiliary spring (as in the Holland & Holland and Lancaster Twelve-Twenty actions) is freely available for throwing open the gun, and whether it is adequate for that purpose. Some guns, such as the Westley Richards Connaught or the Churchill Hercules, which, like several others, use the Smith action, are more accurately described as easy-openers.'
Tim
