American & British 410 Shotguns. Ronald Gabriel
and this phenomenon of a long shot “string” appears to have two physical causes. First, under high pressure, the soft lead shot column results in the welding together of the lead pellets. Second, hot gasses get past the wadding and into the shot charge causing fusion of the pellets. This is called poor “obturation.” Poor obturation also occurs when 2-inch cartridges are fired from 3-inch chambers, because of the difference in case length and chamber depth.
Ultimately then, the long shot string is due to poor velocity-to-pressure ratios. The proof is in the high proof pressures required for the 3-inch 410 bore. The 2-inch 5/16-ounce load and the 2 1/2-inch 7/16-ounce load in the 410 bore require proof pressures of 3-1/4 tons per square inch. For the 12 bore 2 1/2-inch cartridge, it is 3 tons. But, for the 410 bore 3-inch 10/16-ounce load cartridge, the proof pressures are 5 tons per square inch! This may also be expressed in “bars,” whereby one bar equals 14.5 pounds of pressure per square inch. Therefore, one ton equals approximately 138 bars.
Personal Note
This writer graduated from the Stevens under/over 410/22 to the Marlin 410 lever action. This was followed by the Webley & Scott 400 series boxlock side-by-side, and finally rested with the Belgian-made Browning Superposed over/under. A variety of configurations have been used with clay targets and wing game from the single-shot hammer Purdey with 2-inch cartridges to the Winchester Model 42 single-barrel 3-inch cartridge to the classical 410 doubles made by Parker, Boss, Purdey, and Winchester.
Each has its own style, quirks and enjoyments. My workhorse is the Browning in full choke with a 3-inch cartridge for game and a 2 1/2-inch cartridge for targets. Seldom is a hit bird not retrieved. Furthermore, the gap between human technology and nature is somewhat narrowed, making for a more rigorous stalk, hunt, and shoot. Even at appropriate game and ranges, these may still be “idiot sticks”; however, the “idiots” are more content with the bigger challenge and the greater satisfaction. Furthermore, the state of idiocy connotes irrational choices. The 410 use is non-rational rather than irrational. That is, it is emotional, intuitive, and aesthetic, gender ambivalence be damned. Let the big-bore apologists wrestle with that ambiguity. The beauty of shooting the 410, especially for the youngster, is that good form and patience are usually rewarded with a broken target or harvested game.
Ballistics of the 410 Cartridge References
1. Greener, W.W., The Gun and Its Development, 1884, 2nd Edition, Cassell & Company, Ltd., London.
2. Greener, W.W., Modern Shotguns, 1891, 2nd Edition, Cassell & Company, Ltd., London.
3. British Proof House records (London), researched on site 1985 to 1990.
4. Jackson, Tony, ST&CM, 1995, February 9-15.
5. Wallack, L.R., American Shotgun Design & Performance, 1977, Winchester Press.
6. Greener, W.W., The Gun and Its Development, 1910, 9th Edition, Cassell & Company, Ltd., London.
7. O’Connor, Jack, The Shotgun Book, 1965, Alfred A. Knopf, New York.
8. McIntoch, Michael, Shooting Sportsman, 1994, July-August.
9. Askins, Charles, Modern Shotguns and Loads, 1929, Small Arms Technical, 1929.
10. Hastings, MacDonald, The Shotgun, 1981, David and Charles, Newton Abbott, London.
11. Keith, Elmer, Shotgun, 1967, Bonanza Books.
12. Smith, W.H. The American Shotgunner, February 1983.
13. ST&CM, 1990, September 27-October 3.
14. Greevy, Les, Shooting Sportsman, 1999, July-August.
15. Williams, Marshall, Shotgun Sports, 1999, January-February.
16. ST&CM, 1991, March 14/20.
17. Cradock, Chris, Cradock on Shotguns, 1989, B.T. Batsford, Ltd., London.
18. Christian, Chris, Shotgun Digest, 4th Edition, DBI Books, Inc., 1993.
19. Woodhouse, Tim, “Fun With a 410,” The Shooting Gazette, April 2002.
20.Burrard, Major Sir G., The Identification of Firearms and Forensic Ballistics, 1934, 1st edition.
1This is the basis for blackpowder, which generated force by heat expansion.
2 This powder, smokeless, generated force by gas escaping under high pressure.
CHAPTER FOUR
VARIOUS ACTIONS USED TO BUILD THE 410
Another approach in sketching the evolution of the 410 bore is to review the different actions used in their construction.
There is no record of a 410 smoothbore having been made before the development of the breechloader, which goes back to Pauly’s 1812 hinged breech lifted gun that exposed the chambers for loading. LeFaucheux developed, in 1834, drop-down barrels, which then led to the pinfire gun. This was followed by Needham’s invention of the needle fire breechloader action after Daw, in 1862, sparked the commercial success of the hammerless breech. Murcott invented the first lever-cocking hammerless sidelock in 1871. Needham, an inventive genius, patented the first ejector and barrel cocking system in 1874, improved by Greener in 1881 [1].
During this era, action locks slowly evolved in satisfaction and reliability in the form of bar- and back-action sidelocks. However, in 1875, a truly revolutionary action was developed, the hammerless boxlock.
Actions are the heart of a shotgun, the source of its single greatest expense, and the cause of much inflamed debate over the merits of the various action locks. As part of the discussion of the 410 bore’s application to these actions, a summary of the essential components of this history and debate may be illuminating.
1. Sidelocks
The sidelock action is the oldest and has been in continual use since the muzzleloaders of the pre-flintlock era. In rudimentary form, they are found in matchlocks and wheellocks of the late medieval centuries. External hammers, the money part of the lock, go back into the mists of the early second millennium.
The sidelock action comes in two forms, the bar action and the back action. All parts of the action are attached to the side-plate. The back action has the apex of the “V”-shaped mainspring pointing towards the shooter and the mainspring is located behind the hammer (called tumbler if not exposed and, therefore, inside the lock) and trigger. The lock mechanism is behind the axle. The bar action has the apex of the “V”-shaped mainspring pointed forward or away from the shooter. The mainspring is located in front of the hammer and trigger along the “bar” of the action in front of the breech face. This lock mechanism is in front of the axle upon which the hammer swings.
The external plate appearance of the bar action is symmetrically rounded in its posterior aspect (see Figure 1 per Purdey catalog circa 1900).
The back action has two configurations. The 19th century and early 20th century back-action sideplate is characterized by a long, lean, tapered elegance. A later appearance in the back-action external plate duplicated the bar-action geometry, except that the visible pins are in a different place on the lockplate. For example, with the bar action, the visible stud or pin of the “V” mainspring is located at the most anterior portion of the external plate, the “shoe” of the action body. The back action has no such pin location.
The bar action requires deep inletting along the