Gun design secrets: how subtle differences improve shooting

Some shooters don’t realise that the subtle variances between the major shotgun makers are more than just different branding logos, so Vic Harker explains some of the design characteristics

Pay attention to design, it could be the reason you had that fluke of right on target shots

Despite the efforts of gun writers over the years, the majority of clay shooters take little interest in shotgun design, to the extent few could articulate the difference between one maker and another. Barrel length, varying types of rib, trigger pull and stock configuration some pay attention to, but a significant majority are only searching for a gun they can break more targets with, paying scant attention to anything other than coming upon some magic gun: an Excalibur that will transform them into champions. As to fundamental gun design, how the barrels are jointed to the action, for example, is taken entirely for granted and yet this basic factor alone influences how the gun will both feel and balance to the extent it may impact on the shooter’s performance and for the clay shooter his score.

While Browning created the most widely sold and copied over-and-under with its under bolting, Beretta developed the trapezoidal shoulders, Krieghoff and Remington used the steel shroud and Perazzi created the bifurcated bolt,

The first competitive shooters shot over live pigeon with single barrelled muzzle-loading guns, but it was the introduction of the centrefire cartridge that more than any other factor influenced the design of the breech-loading shotguns we use today. From loading powder, shot and wadding into the shotgun barrel’s muzzle ends, to all these things plus the primer in one convenient package, took firearms design from cumbersome, slow-to-load single-shot muskets to the machine-gun in three decades. During that period the breech-loading shotgun as we know it today was spawned. The first breech loaders were greeted with suspicion by some and a competition developed between gunmakers to devise the strongest and therefore safest method of locking the barrels to the action.

A French gunmaker, Casimir Le Faucheaux, is credited with the first successful breech-loader, together with the first efficient self-contained cartridge, which he patented in 1835. From then on, for the rest of the 19th century and beyond, in which the centrefire cartridge continued to be improved, gunmakers continued to develop the breech-loading shotgun and most importantly the securing of the barrels to the action.

Tulio Marengoni with Pietro Beretta and other Beretta staffers

At this time, it was the side-by-side shotgun that found the most favour with gunmakers. The over-and-under presented a number of complex design problems, to the extent that for the time being, manufacturers were content to perfect the side-by-side, for which there was a ready market. In a period of less than 50 years the sidelock and boxlock side-by-sides, reached a pinnacle of efficiency that left little for improvement.

In London, a number of fine gunmakers satisfied the needs of the landed gentry with ever better improvements to the sidelock gun. Meanwhile in Birmingham, vast numbers of boxlocks of good quality were produced that met the requirements of those less wealthy. It should be understood the market was perfectly satisfied with these guns and it was the gunmakers themselves who were looking for something different to stimulate sales, so they looked at the possibilities of the over-and-under.

It posed challenges in how to adapt the lockwork and to joint the barrels to the action, as well as create an attractive appearance. Some early over-and-unders were far from good looking and makers quickly found that by merely putting a pair of barrels on their side and incorporating the bolting as with a side-by-side did not create an elegant appearance. Eventually, however, as is often the case in periods of intense inventiveness that typified English gun making at the time, there arises one man who has at least most of the answers.

Beretta, Krieghoff, Perazzi and Remington all owe a lot to the great British gunmaker, James Woodward, dubbed the father of modern shotguns

James Woodward’s take on the over-and-under dispensed with under-bolting, the locking bolt instead taking the form of a U shape coming forward each side of the breech face to locate with bites each side of the bottom barrel. Other bearing surfaces were machined from the barrel lumps, which, on the closure of the gun located with wedges integral to the actions interior walls. This system was strong and durable and superbly elegant. Take apart a Perazzi and you will see the same principles employed.

In contrast to James Woodward’s gun, John Browning’s over-and-under, manufactured by Fabrique Nationale from 1925, demonstrates that the great inventor had no qualms as to his gun having a deep action. Employing substantial under-bolting, it is undoubtedly the best-selling superposed gun of all time. The barrels pivot by way of a forward lump doubling as a barrel hook on a full width cross-pin. Rear lumps also locate through the floor plate of the action body with a full width locking bolt under the breech face, on closure of the gun it moves forward to lock with a reciprocating bite under the bottom barrel.

Perazzi shotguns of today owe a lot to the great British designer James Woodward

The popular success achieved by John Browning’s over-and-under did not go unnoticed by the gunmaker Beretta. Like Fabrique Nationale in Belgium, the Italian company designed and produced military and civilian weapons in great numbers. It also had its own John Browning in the form of Tullio Marengoni, and he already had his own ideas as to how a Beretta Sovraposto (over-and-under) should be.

After many experiments, he had concluded that the forces generated by the explosion of the cartridge, rather than tending to blow the barrels and action apart, actually forced them together. On this basis, his over and under would, therefore, dispense with any kind of under-bolting Browning employed. Instead, he would locate his gun’s security above the explosion of the cartridge thus working with the forces they generated.

Marengoni’s design also had another benefit, without any form of jointing below the bottom barrel, the SO sidelock would feature a svelte low-profile action. The rest is history, Beretta became and remains one of the largest producers of high quality shotguns in the world and all of them incorporate Marengoni’s original concept for Beretta’s first Sovraposto.

Side-by-sides were simpler to design than the over-and-under and manufacturers built them in massive numbers

In modern terms, it may be true to say the over-and-under shotgun falls into two categories, the under-bolted gun or those with bearing surfaces at the sides of the barrel’s breech ends and the locking bolt above them. That would, however, overlook one of the most successful over-and-unders of modern times, the Krieghoff K-80. This gun’s ancestor was the Remington Model 32 designed by Crawford C Loomis.

After the second world war, Remington had dropped the M32 from its line, so a group of enthusiasts took the gun to Germany and persuaded Krieghoff to recreate it. The Germans  agreed and have improved the gun immensely over the decades. Both sides of the Atlantic considered their clay gun of outstanding quality and design, but as to the origins of the steel shroud that locks the barrels and the action together remains a mystery.

At the highest levels of the sport remains a behind-the-scenes battle between the most prominent gunmakers for the patronage of the world’s best clay shooters. An Olympic gold medal or a world championship can sell a lot of guns and for some time this contest has been between Beretta and Perazzi. It, therefore, seems that in terms of design, top shooters can be divided between those who favour the cross bolted locking design of the Beretta DT11 and the bifurcated bolted Perazzi, though I doubt that it’s quite as simple as that.

Did you know?

Clay shooters used to have to load the powder, the shot, and wad into the shotgun barrel’s muzzle independently, until the birth of the centre-fire cartridge we use today that is loaded into the breech part of the shotgun’s action.

This article originally appeared in the July 2017 issue of Clay Shooting magazine. For more great content like this, subscribe today at our secure online store

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Posted in Advice and tips, Features, Modern Greats, Skeet, Sporting, Technical, Trap

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