It is well known that the early smokeless powders had a tendency to decompose and attack the metals. For instance, the 7 x 57 cartridges that the Spanish government purchased from DMK in the 1890’s were internally varnished to prevent the gunpowder to attack the case from the inside. The same was true for the first lots of spanish made ammunition in this caliber; I don’t know when this practice was abandoned.
But I didn’t know that the same problem could be related to black powder, and that in the US a company named Coe Brass had invented, in 1876, a brass-copper metal blank that would prevent this problem. The blanks were apparently sheets of brass and copper bonded together, by a mechanical process. The brass face would appear on the outside in the finished cartridge, and the copper face would form the interior of the case.
I would like to know if someone knows what happened to this copper-brass cartridge invention. Was it ever adopted by any government or private ammunition factory?
And by the way, which cartridge is the one depicted?
[i]THE COPPER-BRASS CARTRIDGE.
The circumstances which led to the invention of the copper-brass cartridge which is illustrated, were, principally, the reports received in this country, in 1876, relative to great losses by corrosion of cartridges whose shells or cases were made of brass alone, and whose construction permitted the powder to come directly in contact with the inner brass surface of the shell.
It was reported that, under certain climatic or atmospheric conditions, brass shelled cartridges, which had been stored for a certain time in arsenals, were found to have been so badly corroded on the interior as to render them unserviceable, and that the quantity so spoiled, in European countries alone, amounted to many millions; and samples of very badly corroded shells were shown to the inventors and patentees
of the copper-brass shells, Messrs. Leet & Chapin, of Springfield, Massachusetts, in 1876, and there was an apparent necessity that shells possessing all the elastic qualities of brass, and also non-corrosive, should be provided as a substitute for brass shells.
The inventors of the copper-brass shell caused considerable quantities of their shells to be made and tested in the winter of 1876-7. These tests were made by the ordnance officers of this and foreign countries, for the purpose of determining, first, the elastic properties of the compound shell; second, the adhesiveness of the two metals one to the other, under excessive expansive and retractive strains; third, strength under excessive and numerous successive charges of powder; and, fourth, the rigidity of the metal relative to the requisite qualities of anvil-resistance against the blow of the hammer, at the point where the primer is inserted in the head; and the results of said tests wrere eminently satisfactory.
The manufacture of the double metal for the production of the above-described copper-brass cartridge-shells requires that the metals be firmly united previous to rolling; that nothing shall enter into their composition which can in any way render the quality of the scrap metal unfit for re-melting and working; that the metal shall possess such ductility and homogeneousness as will permit it to be rolled, drawn, annealed and headed, and in every way treated, in the manufacture of cartridges, identically like a single metal sheet. These results are all successfully obtained from this metal, which is manufactured and furnished by the Coe Brass Manufacturing Company.[/i]