The Remington, slim and taut as rifles used to be, wore a scope that was dropped from catalogs long ago. At the time, they seemed right for each other, joined not so much by vintage as by economy of line.

It was a 121 Fieldmaster, a .22 slide-action with an uncanny balance that brought squirrels and crows in front of the muzzle with speed and certainty. Clamped in a sheet-steel mount was a Weaver J4 with a 3/4-inch tube.

Since then, scopes have added girth. Me too. A little, in each case, has proven useful. But like people, scopes too big around the middle neither look good nor perform well.

Back when I was peering through that J4, you could also buy scopes with 7/8-inch tubes (notably the Lyman Alaskan) and with 26mm chassis (Lyman's Challenger and the Stith Bear Cub, plus European models). The one-inch scope, however, gained enough of a following to emerge as the new standard in the U.S.

By the time 30mm scopes appeared Stateside a couple of decades ago, they were upstaging 26mm models in Europe. Big has gotten bigger. Schmidt and Bender now offers 34mm scopes in its tactical line. And just as today's shooters are buying into higher magnification, they seem enamored with oversize tubes.

"A 30mm tube is stronger than a one-inch," an engineer at one optics firm told me. Then, perhaps to add something useful to the obvious, he leaned over, "That's all the benefit you'll see in a hunting scope, unless the erector assembly is also oversize."

He explained--after closing his office door--that many 30mm tubes feature the erector lenses used in comparable one-inch scopes, so there's really no optical advantage.

"You do get increased latitude in the windage and elevation adjustments, because the erector assembly has more room to move." That's jolly good news if you must dial up lots of elevation for very long shooting or correct laterally for a skewed mount. Otherwise, you might as well stay with the one-inch tube.

"Strength is an academic issue," he concluded. "Unless a horse rolls on it, or you drop your rifle off a cliff or drive over it, you'll never test the durability of a one-inch alloy scope body."

Many shooters believe that 30mm scopes are brighter than comparable one-inchers. They're not. Brightness is determined by exit pupil, a function of the front lens diameter and magnification--and, of course, by the quality of and coatings on the lenses.