Union Metallic Cartridge & Cap. Co

This is a copy of the 1866 Sales sheet for Union Metallic Cartridge and Cap Co. There are a couple of interesting listing on it. Notice the top row, right end cartridge. It is listed as "No. 56–[color=red]Calibre 44[/color]"
Of course this is a .56-46 Spencer. I wonder why it is listed as “Calibre 44”? Does anyone know what rimfire the “No. 61” is supposed to be? The other side of this sheet says “The cuts represent the exact size of each cartridge”. This is not true or the reproduced image has been shrunk somewhat. The No.58 (.58 Musket) image has a case length of aprox. 1.00 inches. Actual length is about 1.15-1.20 inches. But for what it is worth the iimage of the No. 61 measures aprox. as follows Case Length: 1.20 inches; Head 0.66 inches; Bullet 0.53 inches. My guess is this is supposed to be a .52 Sharps & Hankins or .54 Starr. Any other guesses?

Robert Buttweiler was asked about that #61 in the February, 1996 issue of Gun Report when he was editor of the cartridge collumn and he was unable to positively identify it. He included a Crittenden & Tibbals advertising sheet that shows many of the same cartridges as on the aUMC&C Co sheet, and the #61 is identified as ‘Adapted to Musket’. If drawn to scale, the diameter of the case of #61 is a little larger than the Spencer cases and a little smaller than #58, which is identified on the C&T sheet as ‘Adapted to Springfield Musket’.

I’m going to guess that the No. 61 is actually a .54 Starr.
Look at the picture in Hoyem, Vol. 1, Pg. 154, #RFR 31. It looks just like the No.61. The date is correct and the diminisions are aprox, the same as the drawing.