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Muzzleloading Shotguns and the "Elevating Rib"

posted Apr 27, 2011, 11:42 AM by Peter Lucas   [ updated May 16, 2011, 10:13 AM ]

     Lately, I have been experimenting with "gun fit" on some of my old Side by Side guns. Specifically, I have been attempting modify an old SxS gun so that it fits more like my modern shotgun.  Ultimately, my goal is to modify and restock an old, muzzleloading Navy Arms Side by Side for use on the Skeet field. 

    Like the vast majority of today's shooters, my modern Skeet gun is an Over and Under.  The Over/Under gun has a narrower sighting plane than the Side by Side configuration. This narrower barrel profile allows for a more accurate sight picture of  the lead on the sharply crossing birds at Stations 3, 4 and 5.  My modern Skeet gun also has a relatively high rib.  The high rib allows you to shoot with your head in a more upright position.  The more upright head position allows your eyes to be level while shooting resulting in more natural vision.  The high rib also reduces the tendency to lift your head. 

      My goal has been to apply these seemingly modern ideas regarding gun fit to the traditional side by side muzzle loading shotguns.  It turns out that the idea shooting an upright head position is nothing new. Muzzleloading shotguns from the 1800s often have what are termed "crooked" stocks. These "crooked" stocks had a drop at the comb of as much as 4 inches.  Old guns with large amounts of drop seem un-shootable for those of us who are accustomed to placing our check bones firmly on the comb of the stock.  However, gunsmiths of the 1800 never intended for the check to placed on the comb of the stock.  Instead, the shooter was to hold his head erect and rest is jaw on the side of the stock.  This requires the shooter to keep a very upright shooting stance. When the old guns are shouldered in this fashion, you will discover that you are looking directly down the sight plane of the barrels. 

    There have been a number of explanations for why shotguns from the 1800s are adapted this style of shooting.   One possible explanation for the upright shooting style has to do with the nature of flint and percussion ignition systems.  When the flint strikes the frizzen and ignites the powder in the flash pan (or the percussion cap explodes), there is a natural tendency to try to keep your head and face as far away from the flash as possible.  This is best accomplished by keeping your head up.
Another possible explanation relates to philosophy regarding the manner in which wing shooting should accomplished.  The early wing shooters strongly believed in instinctive shooting is that the subconscious must be allowed to apply the forward allowance necessary to break the target, with the eyes exclusively on the target (not the barrel).  With this type of philosophy, you would most likely not want the shooter to rest his check on the comb, which would increase the tendency to consciously sight along the barrel plane.  Finally, remember that shooters from the 1800s started from the low gun position, rather than having the gun mounted. As the gun was mounted, the gunner would shrug his shoulder up so that the gun comes to rest under his eye, bring the gun into the correct orientation. By contrast, most modern shooting instructors encourage the shooter to keep his shoulders in a natural level position.

Joseph Manton

Joseph Manton is considered to be the father of the classic side by side shotgun as he established the final form of the gun. Over the years, ignition systems changed, and mechanical refinements followed, but the form of the double from Manton's shotguns remains.
Manton was born in 1766.  He apprenticed as a gunsmith between 1780 and 1789 first for a gunmaker in Grantham, Newton and later for his elder brother John Manton.  At the age of 23 in 1789 Joseph struck out on his own and began experimenting with various improvements to firearms and related accessories. By the mid 1790s, Joseph Manton was producing about 100 weapons annually, including both cased duelling sets as well as fowling pieces - the precursor to what would become familiar in the form of the shotgun.  Manton gained a reputation for both building technologically advanced guns for the time and guns of superior craftsmanship.   Many of England's finest gunmakers, including James Purdey, apprenticed under Joe Manton.  
   Accepting that many original SxS guns were designed for an upright shooting style lead me to consider what would be necessary to make the old guns handle more like my modern gun.  Experience told me that simply raising the height to the comb does not make a SxS  feel like an O/U.  Side by Side guns naturally have a lower profile than their O/U counterparts.  While raising the comb helps, it is not the complete answer.  At a minimum, the SxS guns would need an elevated rib which would provide a single, narrow sighting plane. 

    Many modern SxS guns have a high ventilated rib running between the two barrels. However, the
idea of having an elevated center rib on a side by side muzzleloading shotgun is nothing new.  Indeed, a patent for a raised rib  (or more properly, an "elevating rib")  was obtained by none other than Joseph Manton in 1806.    

       Manton experimented with, and ultimately patented, the idea of having an high rib running between the two barrels of the side by side shotgun.  The gun pictured at the top of this Article was made by Joseph Manton in approximately 1818.  The high "elevating" top rib is apparent in the picture.  Notice that the high rib is carried all the way through the tang of the gun.  Another example of Joseph Manton's elevating rib is found in the two pictures immediately above. This example dates to approximately 1815.  This gun carries a wide concave elevating rib.

    The correct term for the Manton rib is the "elevating rib" rather than an "elevated rib."  The reason is that the purpose of the rib was to change the point of impact rather than to simply raise to sight plane.
Manton's elevating ribs taper downward toward the muzzle of the gun.  By the time the elevating rib reaches the muzzle, it is generally flush with the top of the barrels. As a result, the "elevating rib" creates an incline plane which causes the line of sight to be below the axis of the bores. A number of Joe Manton's guns will have his name and the words "Patent Elevation" engraved on the top rib of the barrel. In his patent for the elevating rib, Manton states that the purpose of the invention is to give the barrels elevation to throw the center of the charge of shot up to the object.    No attention is given to the fact that the rib provides a flat sighting plane, which is the commonly accepted purpose of the elevated rib on a shotgun today. 

  
 
Whether or not Joseph Manton's "elevating rib" was really a novel invention was the subject of much debate.  Both Peter Hawker and
William Greener credited Joseph Mantion with the invention, which they believed had great value to the development of the gun.  However, Joseph Manton was not able to successfully enforce his patent for the elevating rib. 

    In a case of sibling rivalry, Joseph Manton sued his brother, John (whom he had apprenticed under) for infringement of two patents, including the patent for the elevating rib.  The brother/defendant (
John Manton) argued that the elevating rib was a "pretended invention . . . used before Joseph Manton was born, or at least long before he ever thought of taking out this patent."  At trial, John Manton conceded that the idea of in having a solid elevated piece of metal running the length of the barrels was new.  However, John Manton argued gun makers had been building guns which were high at the breech and a low at the muzzle for years.  John Manton contended the fact that this incline plane was connected with a solid rib did not constitute a novel invention.  The jury apparently agreed John Manton and refused to award damages to Joseph Manton based on an infringement of the "elevating rid" patent .

 
    Many of the surviving guns produced by Joseph Manton have an elevating rib.  These guns include both flintlock and percussion guns.  However, many of Manton's guns did not did not have elevating ribs.  This was mostly likely due to the personal preference of the person for whom the gun was made.  Joseph Manton's guns were expensive and those sportsman who could afford a Manton gun would expect the gun to be built to their specifications.  Based on the surviving guns, it appears that the majority of Joseph Manton's customer did not order their shotguns with elevating ribs.  In addition, sportswriters of the period opined  that a rib that extended above the barrels made the gun made the gun "unwieldly."  Shooting Simplified by James Dalziel Dougall (1857).  Consquently, many of Manton's customers likely opted not to have have elevating ribs on their guns.  

 

Patent Application for Elevating Rib

To all to whom these presents shall come, I, Joseph Manton, . . . do hereby declare, that my said invention is an elevated top piece, or top rib, for double gun barrels, which said top piece, or top rib, must be made high at the breech ends of the barrels, and tapering off to the muzzles: the intention of [which] . . . is to give the barrels elevation to throw the center of the charge of shot up to the object aimed at, at the distance required;  . . .This improved top piece, or top rib, may be worked solid out of the barrels, or brazed, soldered, or fixed on, or made hollow or part soldered and part hollow, or may be partly continued on the barrels, so there is sufficient length to direct the eye to the object. This elevated top piece, or top rib, may be made of iron, steel, brass, or any metallic or other substance that will answer the purpose, and may be grooved out in the usual manner, or made flat, round, or any other shape or form, according to fancy, . . .. The advantages of this elevated top piece, or top rib, arc, that sportsmen will be less liable to shoot under their game, and tho aim will be more direct and less confused, and that alight double gun can be made to throw the middle of its charge of shot up to the object aimed at, at the distance

Source:
A collection of the most important cases respecting patents of invention and ... By John Davies (of the Rolls Chapel Office.)

   
Following Joseph Manton's death, the elevating rib was almost entirely abandoned by British gunsmiths.  This was probably due to a number of factors, first the breech end of the barrels are thicker than the muzzle.  Consequently, the line of sight is not parallel with the axis of the bore—giving a similar result as produced by the elevating rib.  In addition, gunsmiths began to better understand the effect which regulating the height of comb on the point of impact of the gun.   See:
British rural sports:comprising shooting, hunting, coursing, fishing, hawking, racing, boating, pedestrianism, and the various rural games and amusements of Great Britain; John Henry Walsh (F. Warne, 1868)

Joseph Manton and Peter Hawker

Joseph Manton's fame as a gunsmith was in part due to his relationship with Peter Hawker, the most influential gun writer of the 1800s.  Hawker's classic book, Instructions to Young Sportsmen was considered to be the bible for information regarding wing shooting.  Joseph Manton and Peter Hawker were close personal friends and Hawker used two of Manton's guns for most of his hunting.  This sketch was included in the Eighth Edition of Instructions to Young Sportsmen.    Hawker is shown mounted on the white horse in the center of the sketch and Joseph Manton is shown standing next to Hawker holding a shotgun.  It was unusual for a tradesman, such as Manton, to be invited on a hunting trip by the members of the upper class, such as Peter Hawker.  
    After looking at the pictures of the several Joseph Manton guns with "elevating ribs", I decided to fashion an "add on" rib for one of my old Side by Side cartridge guns.  My rib was not true to the Manton design because it does not tapper towards the muzzle end of the gun.  In addition, my add on rib is approximately 1/2 inch high, which appears slightly higher than Joe Manton's elevating ribs at their highest point near the breech of the gun.  My initial prototype was made from wood and painted black.  While not completely true to Joe Manton's design, my add on rib made the sight picture of my Side by Side much closer to that of my modern gun. My scores on the Skeet range with the gun also improved.  From what I can tell about Joe Manton, it appears that he was an experimenter would would not be offended by someone attempting to make his designs more functional.  I plan on getting some black Delrin plastic and continue with the experimentation.  











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