I pulled the Remington Peerless out of its case, cracked it open to check the chambers, snapped it shut and slid it into the saddle scabbard. "An over/under. Good," said guide Bob Tinker without offering a single word of explanation.

"Over/Unders good," sums up the modern attitude concisely.

Perhaps Tinker, who takes armed strangers hunting on horseback for a living, interpreted the O/U as a hopeful sign that I was a serious and therefore safe shooter. Well, I was certainly safe that morning, especially if you were a prairie grouse. Enough about me. We were talking about smoothbores and the fact that everyone recognizes the O/U instantly as shotgunning's top gun these days.

Yet if your local gunshop is anything like mine, when you surveyed the gunrack in the late 70s the only O/U in sight was inevitably a lonely Citori stuck in among a forest of 1100s and 870s. Today my local store does a brisk business in O/Us, especially in the weeks leading up to pheasant season.

Have O/Us achieved such widespread popularity over the last 20 or so years because they're a fad or because they truly do represent some ultimate refinement in shotgun design?

O/U fans (and I am one) maintain their favorite gun succeeds by blending the best features of repeaters and side by sides. The compact action of a double gun -- whether a horizontal or vertical double -- measures about three inches shorter than the action of a pump or auto. Moreover, much of the weight of a break-action gun lies concentrated between the shooter's hands. An O/U pivots quickly around that concentration of weight, handling faster and more responsively than a pump or auto.

At the same time, the O/U offers the single sighting plane of the repeater, an advantage the side by side can't claim. When you shoulder a side by side, you get the sensation of looking up a short section of highway. And there's absolutely nothing wrong with the broad expanse of a side by side's barrels in the field (actually, there's quite a bit right with it). In clay target games, however, the narrow sighting plane of an O/U or repeater wins, period. Even though shotguns are pointed, not aimed, clay target competitors point them very precisely. Top shooters can put the narrow blur of an O/U's top barrel exactly where they want it in relation to a target.

O/Us enjoy another small advantage over side by sides. Target shooters believe an O/U's top over bottom barrel arrangement kicks less and delivers allows them to deliver their second shot faster than they can with any other gun. O/Us typically shoot the lower barrel first. Because the bottom barrel lies below the line of comb, the gun recoils straight back into the shoulder upon firing. Besides being less painful, "straight-line" recoil comes back, well, in a straight line, and it's easier for the shooter to keep the gun on target for the second shot. Side by sides, in comparison, jump both up and to the side. Chances are you wouldn't notice any difference in the field, but in clay target competition where recoil fatigue becomes a real factor and a fast, well-placed second shot can make the difference between an X and O, the O/U has the edge.

Granted, these are fine points. There's no doubt serious competitors could post good scores with side by sides. But none of them choose to. They play to win and the O/U gives them an advantage. That, as Walter Brennan used to say on TV, is no brag, just fact. Side by sides haven't done much in clay target competition since 1936, when Dick Shaughnessy won the National Skeet Championships with a 16 gauge Model 21. Similarly, pumps once dominated skeet; now they're artifacts. You won't see them on a sporting clays course either except in special events.

While autos hang on in 12 gauge skeet and have made some inroads in sporting clays, O/Us rule the clay target fields. They're reliable and easy to keep clean. They can digest hideous reloads held together with Elmer's glue and pop the hulls back into your hand so you can squeeze one more loading out of them. You can fit O/Us with tube sets and shoot all gauges with one gun. O/Us give you the option of shooting two chokes and, in general, an O/U will outlast a pump or auto under the rigors of thousands of rounds in competition.

As field guns, O/Us can approach classic side by sides in terms of sleekness and dynamic handling while retaining the single sighting plane advantage. For instance, I hunt frequently with an older Beretta. The 28-inch barrels, struck very thin, are long, light and responsive. The forearm is remarkably slender; my front hand lies little more than a quarter of an inch from the bottom barrel allowing the gun to point like an extension of my hands. When I do swing it at a game bird, I see the same narrow sighting plane I'm used to from clay target shooting.

That's what O/Us should be. However, just because a gun has two barrels doesn't mean it has good balance. Many guns made for the American market are bulky, overweight and muzzle heavy. One or two of them are hogging space in my gun cabinet even now. Take my Peerless: its thick barrel walls make for a distinctly muzzle heavy, sluggish gun. The buttstock and actions of my Beretta and my Peerless weigh about the same. However, the Peerless's 28-inch barrels and forearm weigh 4 pounds, the Beretta's 28-inch barrels and slim forearm weigh about 3 1/4 pounds. The Peerless is fine for clay targets, especially skeet, where there are no surprises. But all that weight in the muzzle can make a gun hard to shoot well at birds who flush when they feel like it and fly at angles of their own choosing.

You don't necessarily have to spend a lot of money to find an O/U that handles sweetly. Beretta's Whitewing, in 12 and 20 gauge are among the lightest, nicest handling O/Us I've seen lately, and they list for $1300 which is about as low as O/U prices get. The Ruger Red Label in 28 gauge is a small-framed, scaled down delight. I've recently been impressed with SIGarms Aurora guns made by B. Rizzini as well.

In the field, the one of the best features of a two barrelled gun is safety. Not that any kind of gun is safer than any other, but it's easier to be safe with an O/U. You can flick the lever to open the gun any time you have to climb an obstacle, slide down a bank, jump a creek or unload the gun to see if you've plugged the barrels with mud or snow. It's easy to show people your gun is unloaded by carrying it broken open. O/Us don't scatter empties across the landscape, either. Back home, there's not much to do for cleanup since debris rarely gets into the action.

An O/U allows you to shoot two different chokes. However, unless the gun has two triggers (far more common on side by sides), an O/U doesn't give you an instant choice of chokes; it gives you a selector to fiddle with when you should be concentrating on the target. There's still an advantage, however, to a gun that gives you a second, follow-up shot through a more tightly choked barrel as birds fly away or when you have to deal with a pair of clay targets.

The one place I'd like to try an O/U with a single selective trigger is the turkey woods. A couple of springs ago I missed a gobbler at 5 steps with a super-tight choke that threw a pattern the size of a golf ball at spitting distance. It was a scarring experience. An O/U, with its single sighting/aiming plane, a barrel selector and, say, an IC choke in one barrel, X-full in the other, could deal with the turkeys that stand there and strut at 40 steps as well as the birds that sneak in close and try to sit in your lap.

Although the O/U design possesses some significant advantages for both field and target shooting, we don't buy guns solely on their merits. Whether we admit it or not, we're vulnerable to the whims of fashion. Even hunters barely aware of clay target games still want to shoot what the champs are shooting. How else do you explain away the total indifference with which the shooting public greeted the Marlin and Savage O/Us, the Remington 3200 and even the Browning Superposed whey they first appeared in the 20s and 30s? Back then, pumps and side by sides were the rage, O/Us a novelty.

The Great Depression killed off American side by sides. It wasn't until the booming 1960s that shooters began to look beyond repeaters to double guns again. And when they did, they bought O/Us. Browning successfully marketed the Superposed to hunters and target shooters alike as "the aristocrat of shotguns." Folks without as much to spend could choose among surprisingly well-made SKBs, Charles Dalys and Winchesters from Japan, all of which became available in the early to mid-60s. Italy's Perazzis, with their Olympic gold medal pedigree, racy handling and high price tags nailed down the O/U's glamor gun reputation. And the O/U never looked back.

I'm beginning to wonder, though, if times aren't changing. Not long ago at my gun club, I shot with a man perhaps ten years my junior who casually ground up 50 straight skeet targets while puffing on a fat cigar. Of his target grade Beretta O/U he said, "I can't wait to put this piece of junk away and get my Benelli out for pheasant season."

I looked at his yuppie cigar, the real rattlesnake-head belt holding up his cutoff jeans and pondered his obvious bad taste in bird guns. And I felt the way parents feel when their kids listen to loud, incomprehensible music: on the one hand, disapproving. On the other hand, old and out of it.

There's no question the modern autoloader has made inroads on the O/U's popularity. There's good reason for it, too: autos are reliable, soft-kicking and easy to shoot well. It's only been 15 years since the first all-load autos appeared on the market. A generation of shooters has grown up with autoloaders that shoot 2 3/4 and 3 and now 3 1/2-inch loads interchangeably. The best of them, the Browning Gold, the Beretta 391 and the Benellis perform with almost monotonous reliability. With their alloy receivers they're long and light, a combination that's easy to shoot well. Many of them are lighter than some of the more popular O/Us and they hold more shells. It's worth noting, I suppose, that the price of a Beretta or Benelli now approaches that of an entry level O/U, and certainly price equals prestige in some people's minds.

You need only look at the winner's circle of a Sporting Clays event to see Browning Golds and Beretta 391s horning in on the O/U's territory. Everyone shoots better when they're not getting kicked; a gas gun can weigh less than an O/U and still deliver milder felt recoil. Even as autos challenge O/Us in Sporting Clays, the side by side gun is undergoing a much deserved revival: Ruger's new Gold Label and Weatherby's reasonably priced Orion and Athena side by sides promise to be great hunting guns that may chip away at the O/U's sales.

Yet O/Us will keep on winning at clay target games, especially international trap and skeet. In the field, they'll kill birds as they always have. When all is said and done, chances are the over and under will still stand over and above the rest.