Self-opening systems are a British thing — or so they say…And yet, one of the first if not the first self-opening mechanism was patented by Antonine Lebeda, Jr. It was used to assist the opening of Lefaucheux patent break-open guns, with the fore-end permanently hinged to the action body (systeme Lefaucheux). The self-opening part of the mechanism was a spring-loaded lever that acted on a lengthwise channel in the barrel lump.
Then came Frederick Beesley (1846-1928), who began his gunmaking career as a stockmaker at Purdey’s and opened his own business in 1878. On January 3, 1880, he obtained the British patent №31 for «hammerless self-opening spring-cocking gun». Beesley wrote to Purdey about this invention even before the patent was granted — on December 18, 1879. By January 1880 they prepared an agreement, by which all rights under the pending patent passed to Purdey for 20 pounds and the royalty of 5 shillings for each of the first 200 guns. Purdey offered to pay 35 pounds of royalty in advance, and obtained full rights for a single payment of only 55 pounds. Then Beesley, as Purdey’s assignor, patented his system also in Belgium (patent №52603 of September 20, 1880) and the U.S. (patent №250189 of November 11, 1881). The first gun on the new system was finished by Purdey in 1880.
Yet, Beesley did not invent his system completely from scratch. It was based on the principle of the rebounding lock. Rebounding locks first appeared on hammer guns, with two Wolverhampton lockmakers, Thomas Rigby and John Stanton, competing for the title of their inventor: there was only 3 days difference in dates between their 1867 patents! By the way, Beesley referred to Stanton’s patent in description of his own invention. Some time later Beesley, also as an assignor, obtained the British patent №823 of February 14, 1883, and the U.S. patent №10281 of February 6, 1883. These patents clarified some nuances of the system. It is not clear why he needed the «second edition» of the patents; probably it was only to extend the patent protection time.
From the point of view of mechanics, Beesley’s action is a system of a V-shaped spring and a tumbler that rotates around the axis A (Fig.1). When compressed, the spring acts on the upper pin on the tumbler with the force of P1, and since this force is applied at a shoulder L1, it creates torque of M1 = P1xL1 on axis A. The lower arm of the spring acts on the lower pin of the tumbler with the force P2, which creates torque M2=P2xL2 in the direction opposite to M1. When the spring, compressed by the cam (5), is released, the tumbler will turn around the axis A until the torques M1 and M2 are equal (Fig. 2). This simple principle is the basis of Beesley-Purdey action.
Figure 1 illustrates the moment when the lock has been fired. On Figure 2 you can see the moment after the gun has been opened. The mainspring is then set free and brings the tumbler to full cock. The mainspring is compressed with the gun is closed (Figure 3).
The lower arm of the mainspring is connected to the tumbler by an additional link, known as swivel (7). The swivel adjusts the trajectories of travel of the tumbler (1) and the mainspring (3), and also compensates for the fall in torque on the last part of the tumbler’s motion due to decrease of the mainspring’s pressure (the pressure is at maximum when the mainspring is fully compressed).
When the gun is closed, the barrel flats press on the pads (12) that protrude from the action flats. The pads go down, rotating around their axis, and push the cocking rods (13). The cocking rods act on the cams (5), causing them to rotate and compress the mainsprings. To decrease the friction, a roller (6) is fitted into the upper arm of the mainspring. When the gun is opened, regardless of whether the locks have been fired or not, the mainsprings produce torque that is transferred to barrel flats through the system of cam — cocking rod — pad, and ensures the self-opening effect.
Purdey made three variants of Beesley’s action. Two are known as 9-pin locks, because they have 9 clearly visible ends of screws and pins of the locks on the external side of the lock plate. One of them did not feature an interceptor, but was fitted instead with a safety catch that locked the sear. There was also a 7-pin lock, without intercepting sears and with lighter bridle. This variant was also used on the company’s single shot guns; there were only 59 of them made. The modern range of Purdey’s includes also a «pinless» variant of the Beesley’s lock, that is, the lock where all pins except the tumbler axis are made integral with the lock plate.
There have been numerous attempts to «improve» Beesley’s patent since its invention to this day. However, I do not know of any «improved» version where the changes actually altered the basic principle of Beesley’s action. They say that Henry Atkin’s version cocks more smoothly than the Purdey’s version, because Atkin allegedly improved Beesley’s system. As a matter of fact, Atkin’s improvements have to do with the ejector linkage: in Atkin’s guns the ejector is triggered by a separate lever that is acted on by the sear. The subjective feeling of «smoothness» probably results from the fact that Henry Atkin improved the shapes of conjoining elements of the lock.
Another original design of ejector link can be seen on the gun made in 1927 by Joseph Defourney (younger brother of Antoine Joseph Defourney) for Louis Branquaert.
It is amazing, but even the greatest gun writers made mistakes in their description of Beesley’s action. For instance, both Greener and Burrard claimed that the system works because one of the arms of the mainspring is stronger than the other. Only in 1971 Gough Thomas (Godfrey Thomas) Garwood, in his Gough Thomas’s Second Gun Book, corrected this mistake. Mr. Garwood quoted Richard Akehurst’s Game Guns & Rifles (1969), which stated that Beesley’s action used the energy of both limbs of the mainspring at all times. This is quite evident, if you pay attention to the fact that the mainspring is free to rotate around its axis. Therefore, from the point of view of mechanics, the mainspring is an elastic lever.
With so many parts to be fitted, and so many parts that interact with each other, Beesley’s action requires the highest degree of precision in making. The mainspring is very difficult to make, due to its sophisticated geometry, and its strength has to be just right: strong enough to prevent misfires but not too strong to make worse the basic ergonomic incorrectness of having to overcome the tension of the spring when closing the gun. Still, the Beesley-Purdey system is a mechanical masterpiece that has been keeping its admirers in awe for over 130 years. Many gunmakers, including Belgian, were able to reproduce it, but only James Purdey & Sons Ltd. still makes it.
Frederick Beesley developed another self-opening system (British patent №425 of January 2, 1884, Belgian patent № 67064 of December 1, 1884, U.S. patent № 320040 of June 16, 1885).
As far as we can judge from the description, Beesley’s idea was to simplify the action by replacing the cocking rod and the V-spring with an one-arm spring that would also cock the tumbler. Self-opening was a side effect of the mechanics of compressing the mainspring with closing motion of the barrels. Beesley used this system in his boxlock guns.
Beesley’s patent rights were acquired by Charles Lancaster & Co owned by Henry Thorn. Under the license of Lancaster, the shotgun «The Triumph» was produced by the American company Crescent Fire Arms Co. Thorn’s gunmakers were able to adapt this principle to sidelock guns as well. Charles Lancaster & Co offered Beesley patent sidelocks, known as «Wrist-Breakers», until 1920s.
Another self-opening boxlock design was developed by Henry Tolley. He didn’t only patent his system (British patent №10101 of July 12, 1884; U.S. patent №315858 of April 14, 1885), but made a few guns on that. Evidently, Tolley’s system achieves the same ends as Beesley’s, but is much simpler.
Since the late XIX century British gunmakers developed numerous self-opening systems. In modern terminology some of them are classified as «assisted-opening» and «easy-opening». Among these, one can’t fail to mention the self-opening system of Henry Holland and William Mansfield (British patent № 202405 of May 18, 1922), used by Holland&Holland for their «Royal» model, and also by some Spanish companies. According to Donald Dallas, the first Holland&Holland self-opener, №30595, was finished on April 27, 1923.
The principle of Holland & Mansfield self-opening mechanism is as simple as genius. A push on the action above the hinge pin naturally creates torque that tries to open the gun. This torque is created by a simple coil spring, fitted neatly between the front barrel lump and the fore-end lump.
Assisted-opening and easy-opening systems are outside the scope of this paper. I shall only say that the distinction between self-opening, assisted-opening and easy-opening designs is largely arbitrary, and not all experts agree on it. Many «assisted-opening» and «easy-opening» systems can be turned into full-scale self-openers by minor changes in schematics, or even the power of the springs.
Original self-opening systems were developed not only in Great Britain, but also in Belgium. One such gun, made at the beginning of the XX century, is illustrated here. I don’t know yet who patented this action, or whether the system was patented at all, but there’s no doubt it’s Belgian. This system achieves the same ends as the Beesley-Purdey system. In the Belgian system there is more room for the actioneer. In spite of its apparent sophistication, the Belgian system is easier to put together and regulate. This is, I believe, one of the reasons it exists.
Two Belgian self-opening systems that deserve special attention were designed by Defourney, a box lock and a side lock. Apart from Belgium (1907 patent), Defourney had his system patented in France (patent №464.536 of November 7, 1913) and Great Britain (patent №13189 of May 29, 1914). The gem of this design is the flat mainspring (4), with one side hinged and the other leaning against the tumbler (2). The mainspring is compressed when the gun is closed. The residual pressure of the mainspring after letdown of the tumbler is siffcient to ensure self-opening effect. It’s worthy of note that Defourney used the same principle as Tolley did 13 years earlier.
Let us consider Defourney’s self-opening sidelock system. The long mainspring (2) has one end fixed on an axis, and its other end presses against a pin protruding from the tumbler. The tumbler is cocked when the gun is opened, by a long, spring-loaded cocking lever (3). When the gun is closed, the pad (6), being pressed by the barrel flats, rotates around its axis and compresses the mainspring through the cam. The contact areas between pad and cam, and between cam and mainspring, are fitted with rollers for smoother operation.
«Shotgun Technicana» by David Trevallion and Michael McIntosh mentions a self-opening boxlock gun made by A. Francotte in 1937. The same action was used by Etablissements Braekers of Liege in the late 1920s. The tumbler is cocked in the traditional manner, by a cocking lever when the gun is opened. When the gun is closed, the pads are pushed into the action body by barrel flats, and compress the mainspring. After the tumbler is let down, residual pressure from the mainspring is acting on the barrel flats through the pads and ensures self-opening effect.
This action didn’t enjoy much popularity. Neither did a W.C. Scott & Son patent on a similar principle. On December 3, 1878, William Scott and Thomas Baker obtained the U.S. patent №210436 for «Improvement in breech-loading guns». This patent protects a number of principles, including those where the tumblers are cocked and the mainsprings compressed by pressure of the barrel flats on the action flats in closing the gun.
The pressure of the mainspring is pressed via the shaft to the barrel block, ensuing self-opening effect.
Russian gunmaking, apart from Beesley-Purdey system used by TsKIB, knows only one independent self-opening design. You can see it on the gun made by Tula Armory in 1934 for the All-USSR Industrial Expo, under Tula’s gunmaking patriarch Alexander Ivanov.
Self-opening systems have proven their functionality and reliability. Most of them are newer and more technological than the Beesley-Purdey system, but none is as ingenious and neatly designed as the unsurpassable masterpiece of the prominent Victorian gunmaker.