Author Topic: 1855 Birmingham Proof Testing  (Read 1275 times)

Offline JCKelly

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1855 Birmingham Proof Testing
« on: December 28, 2016, 11:53:45 PM »
Found this in an old copy of The Journal of THE ARMS & ARMOUR SOCIETY VOL VII No 4, DECEMBER 1971
This article was taken from a publication which arose from an 1855 meeting in Birmingham. It was written by John Goodman, chairman of the Small Arms Company of Birmingham:
page 104 - In 1815, it was found . . . No change was made in the system pursued til 1855, when the inventions of modern times called for fresh regulations . . . Under the previous one, barrels were proved only once, and that in a rather early stage of manufacture. It followed that certain descriptions of guns, as for instance - rifles when grooved, and doubled guns when jointed together - were weakened after proof, and sometimes rendered unsafe. The present Act requires that all such barrels shall be proved twice, once "provisionally," as the Act terms it, and a second time, "definitively," when the barrels are in a finished state, ready for setting up. The first proof may be regarded as for the protection of the gunmaker, to secure him from the loss that would arise from bestowing his labor on an unsound barrel; the second proof protects the user.

In order to show the degree of security afforded by the proof to which the barrels are submitted, it will be sufficient to give, as examples, the two sizes of barrels most in use for sporting and military purposes, showing the proof to which they are submitted. 

                                 Rifle                Double Gun
                              (.577 inch, or about 25 bore)   (12 bore)
Ordinary Charge of Powder
for service and sporting             68 grains                82 grains

Provisional proof charge                       205  grains                        350  grains      

Definitive proof charge                     137  grains                        219  grains

Weight of bullet (conical)
   provisional proof                     715                                     ---

Weight of bullet (conical)
   definitive proof and service             536                                     ---

Weight of bullet (spherical)
   provisional and definitive proof        ---                                  535  grains         

For those few who think it would be cool to shoot one of those long flintlock guns made for the African trade, right up into the 20th century:

In 1672 . . . Liège gunmakers . . . compulsory the proving of barrels. Several subsequent enactments were made on the subject. . . In one of 1819 we find the singular regulation, that all arms not marked as proved shall be seized, except those intended for the slave trade; and, as showing that the dangerous character of guns so made was fully appreciated, Clause 9 requires that under no pretence whatever shall they be put in circulation in the interior of the kingdom, but they shall be sent in packages, corded and leaded, to the border town whence they are to be exported.

The following is strictly JKelly: Provisional and definitive proof at the time was to ascertain the soundness of the weld in the barrel, and whether any harmful defects (like large slag inclusions) were present in the metal used.

Contemporary muzzle loading barrels being drilled from solid, one needn't be concerned about a weld. Nevertheless, some small amount of any steel bar may contain seams or other defects that eluded the mill. I have seen such in 1018 cold drawn steel tubing, which I intended for a pistol barrel, and a number of high nickel alloy bars where I worked.

The better steels used in todays barrels include 1137MODIFIED, and 8620. Steel producers may not consider 12L14  to be suited for high impact applications.

Whatever the steel, it is not a bad idea to proof test it. I suspect such is uncommon at the barrel makers, might like to hear otherwise. Not a bad idea to follow the British practice of "provisional" and "definitive" proof, but that is just my personal opinion.

Tthe last time I attempted to put a table of numbers in my post it came out just as much a mess as this one. Some Nice Man told me how to do it right but I surely do forget.