I dunno how many Bob shot in his life, but it was a bunch. A lot more than 200 anyway.
When I was writing my shotgun book (a period of close to a year) I took 3-5 shotguns a week to the local Sporting Clays range and shot the heck out of them. Tried to figure out why each worked better on some shots and not others, and why. At the same time I observed what other people shot, and with the people who apparently knew what they were doing, I asked questions. I also talked with a lot of top shotgun coaches, including one Olympic coach.
I knew I would be writing the book long before that, and spent the previous couple of years shooting a lot of birds (both upland and waterfowl) in different places with different guns. In fact the research shooting for the shotgun book overlapped the hunting we did for Eileen's waterfowl and upland cookbooks. For 2-3 years we shot the heck out of a lot of shotguns on both claybirds and edible birds, from the Deep South to Canada.
One of the things Bob taught me is that we all have good days and bad days, and judging any shotgun on how we shoot on a bad (or good) day isn't valid. But after a lot of shooting, then we might be able to judge beforehand whether we might be able to shoot any shotgun fairly well. And if we can't, then we might have a fair idea of what might be needed to be done with it.