Keep in mind, however, that the specs for these guns changed over the years. My Armi San Paolo is ten years newer than yours.
Howdy Again
Yes, the specs did change over the years. As I said, the gunsmith at Taylors used a Pietta cylinder for my conversion. Mine is six shots, not five.
Ken Howell obtained a patent on his six shot 45 Colt conversion cylinder for the 1858 Remington chambered for 45 Colt. The cylinder size of the 1858 Remington is not large enough to chamber six 45 Colt cartridges without the rims over lapping. What Howell did was angle the chambers slightly, less than 1/2 of one degree, so that at the rear the chambers were spread out enough to allow six 45 Colt cartridges to be seated without the rims over lapping. He then patented the idea of angling the chambers slightly. Taylors was the sole distributor for his cylinders, he was selling them under the name R&D. At some point Howell sold the rights to his patent to Taylors. He started his own company, Howell Arms, at some point, but because he had sold his patent to Taylors he could not infringe on the patent and offer a 45 Colt cylinder for the 1858 Remington with angled chambers. So all of Howell's 45 Colt or 45 ACP cylinders for the 1858 only have five chambers. When Howell sold his patent to Talylors they began having the cylinders made by someone else, I do not know who.
https://www.howellarms.com/1858-remington
Howell does offer a 44 Colt cylinder for the 1858, with six chambers, since the cartridge diameter and rim diameter of 44 Colt is slightly less than 45 Colt. The chambers for the 44 Colt cylinder to not need to be angled. I read somewhere recently that the patent on Howell's angled chamber cylinder has expired, but I have not seen any changes in Howell's line up of 45 caliber cylinders to reflect that.
My six chambered 45 Colt cylinder for my 1858 Remington can accomodate the slightly larger diameter rims of 45 Schofield too.
Before anyone asks, 1/2 of one degree of angle on the chambers does not affect anything. They are completely safe, and the chamber dimensions on my 1858 cylinder are so tight that my 1858 EuroArms Remmie is the most accurate revolver I own chambered for 45 Colt. More accurate than my Colts, Uberti, or Rugers. The cylinder is so precise that I use it as a cartridge gauge when loading 45 Colt. Anything that does not drop right into the chambers of the Remmie cylinder would still chamber in a Colt, Uberti, or RUger, but I run them through the crimp die again so they will chamber in the Remington Conversion cylinder.
Anyway, this has gotten a bit far afield. Taylors is one of several importers that import Italian made revolvers, but because of the excellent service I have gotten from them, I consider them to be the best of the importers.