Sunday, April 5, 2015

Manufacturing Cartridges in the 19th Century - Part III

In our last couple of posts, we studied how the cartridge cases and primers were manufactured during the middle of the 19th century. In today's post, we will study how the bullets for the cartridges were made. As before, we will study how the process was done at Kynoch, a large British manufacturer of ammunition, which was using the latest technologies and machinery available during that era.

While we have studied cast lead bullets in the past, by the 19th century, the casting method was considered too slow for mass production. Therefore, bullets were made in quantity using machinery. We will see how this was done in that era.

The first order of business was to prepare the lead for bullet making. Pure lead was not used for bullet manufacture as it is too soft. Instead, lead was melted and then, zinc or tin were mixed with the lead to harden it. This lead alloy was then forced out into long round ropes of metal, which were then coiled and loaded onto bullet-making machines.

The bullet-making machines at Kynoch were marvels of mechanical technology at that time. The best machines were capable of measuring out a length of metal, cutting it from the rope, feeding the cut piece into a die shaped like a conical bullet, forcing it in with a conoidal punch and then ejecting the finished bullet into a box. The bullets were then regulated in a press, to ensure that they were as cylindrical as possible. Each bullet was then placed in a lathe and wrapped with a paper patch, which was cut off and twisted while the bullet was revolving in the lathe. The paper patches were then waxed on to the bullet and the bullets were now ready to be loaded.

There were a few advantages of making bullets this way, versus the old casting process. For one, it was faster to manufacture bullets using this method. The bullets were also much more uniform in size, shape and weight than cast bullets. In addition to this, the possibility of casting defects, such as air pockets and hairline cracks, did not occur on these machine-made bullets.

The factory at Kynoch not only made lead bullets, but also made composite bullets (e.g.) jacketed bullets. To make these, the outer jacket was made of a copper alloy. The Kynoch factory used an alloy of 80% copper, 20% nickel, with small quantities of manganese, iron and silicon. This alloy was chosen because it is tough and hard and produces a shiny surface that doesn't tarnish easily. The alloy has a tensile strength of 27 tons per square inch. The alloy was rolled into sheets of 0.04 inches thickness. These sheets were then made into jackets using a process similar to how cartridge cases were made, which we studied earlier (i.e.) the round blanks are punched out from the sheet, then each blank is cut out and made into a cup and then passed to a drawing machine, where the jacket is drawn out gradually to the required length by multiple drawing operations. Unlike making the cartridge cases, annealing and pickling in acid were not necessary between each drawing stage and seven drawing operations were sufficient to elongate the blank into a outer jacket for a .303 bullet. The inner part of the bullets (the cores) were made of a lead alloy. Lead was mixed with 2% antimony and squirted into rods of the required diameter. These rods were cut into pieces of the length desired and each piece was placed into a jacket by hand. The composite bullet was then forced into a die, so that the edge of the jacket was turned down over the base. The final finishing processes consisted of adjusting the diameters of the bullet, trimming and adding the rings at the base.

It may interest the reader to know that some jacketed bullets are still made today, using a similar process. Here's a video showing how Hornady makes jacketed bullets today:

In the next post, we will study how the cases, primers and bullets were brought together to load a complete cartridge. Until then, happy viewing!

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