After many months of work, treatment has been completed on a grouping of four rimfire cartridges recovered from the interior of the turret in 2006 (see blog post from February 18, 2010).
Of the four cartridges, two are relatively complete while the others have fragmented. The image below shows a view of the interior of the cartridge (second from right) in the above image, which revealed a twill textile after it was cleaned. A sample of loose fiber from one of the yarns was removed and identified as cotton after viewing it under the microscope. The textile may have acted as a moisture barrier to keep the powder dry if the cartridge had gotten wet: see passage below.
In the early 1860’s, a wide variety of rimfire cartridges were used with individual types produced for specific weapons. This has lead to speculation that the Monitor’s cartridges could belong to a Ballard carbine, Spencer rifle or carbine, or possibly a Sharps and Hankins’ Navy Rifle. It is important to note, however, that although ammunition was made for individual weapons, some could be fired from different breech loaders.
The information below was taken from a book title “Small Arms and Ammunition in the United States Service, 1776-1865” written by Berkley R. Lewis and published by the Smithsonian. The letters highlighted in pink are several varieties of Spencer ammunition, the letter (t) belongs to a Ballard carbine “Old Model”, and letters (z, aa, and bb) are from the Sharps and Hankins’ rifle and carbine.
Based on appearance from this sample set, the example for the Ballard (t) seems to match most closely to the cartridges that we have.
Below is a list of rifles and carbines in Ordnance Memorandum I as being used in 1863 showing the bore, chamber, and ball diameters for specific weapons. Measurements of the ball diameters from the Monitor’s cartridges are approximately 0.557, 0.552, 0.548, and .554. However, these numbers can’t be considered completely accurate due to some possible corrosion of the lead balls after 140 years under water.
This is an interesting excerpt of a description of the American rimfire cartridge of the Civil War years from a report on the 1867 Paris Exhibition, which quotes a paper read by Captain O’hea before the Society of Arts, of London:
The hunt continues…. If anyone has any additional information out there it would be quite helpful!!!!