When you read this, do not, pray, confuse “overrated” with “bad” or “unsuccessful.” The 9mm Parabellum, for example, is one of the most popular and heavily produced cartridges in the world, and has had a long, long life. But for all its success, there is some nagging doubt about its effectiveness. Does it really pack the power necessary for cops and soldiers and other people who may have to stake their lives on it? And there’s the 7mm Remington Magnum, which has slain game by the freight-car load, and is a perennial high seller, but the round’s ballistics fall short of its “magnum” billing. And so it goes.