They were an importer of Italian made percussion revolvers (and I believe a few rifles) from around 1970 until I've heard early 90's. Haven't heard much more about them. Their firearms were made by Armi San Paolo from what info I've found and understood. Reviews over the years sort of follow the Armi San Marco percussion revolvers. Some say they are poorly made vs Pietta and Uberti revolvers, poor workmanship, steel, etc. Others who have had them follow the same as with Armi San Marco's in that they were pleased with them. I've read that the quality depended alot on what time frame they were manufactured.
Some on the forum here and on others who work on the Armi San revolvers advise of poorly fitting parts and parts that are hard to find and that Pietta/Uberti parts won't fit. My experience with a EuroArms product was my first cap and ball percussion revolver a 1851 Navy in 44 caliber bought in 1972. Didn't think much of it then as I didn't have anything to compare it with at the time, but that '51 Navy 44 while looking nice was a headache. Poor timing, fast wearing internal parts, hammer/trigger sear just chipped for no reason, spent caps fell into the interior frame like leaves falling in the fall. IMO it was a piece of junk, a real learning experience. Still have it but it was damaged in a fire after accidently being mixed up with things destined for a burn pile, a sad but rightful end to it. I'm not sure how Armi San Paolo and Armi San Marco are related if at all as so many of the Italian percussion gun manufactures are interrelated at times and/or owned by larger corporations. A search on the internet has information. Someone with more info and insight may chime in here.