The sidelocks, and for that matter boxlock pairs (obviously made for driven shooting) often got much heavier use, in terms of rounds fired, than a keeper's gun. Not at all unusual to go through 100+ shells in a day on a 250-300 bird driven day. And back when Ripon was shooting, a lot of the driven days were bigger than that. So one heck of a lot of shooting over the course of the season, for those who were serious about it. That's why the preventive maintenance was a particularly good idea. You might not need to change your oil if you only drive your car 5,000 miles in a year. Probably a good idea if you drive it 50,000 miles a year.

But if the preventive maintenance wasn't done . . . easy to see how one can run across a worn-out gun, if it was used for volume shooting.