I believe a cannon owned by a Texan named McGloin was stolen by Mexicans retreating from their defeat at San Jacinto. People still search for it. Much later, TR’s rough riders were given a gift of one or two Colt/Browning machine guns from Lewis Tiffany, a relative of one of his recruits. They had no problem purchasing them. Of course older fully automatic weapons can still be owned in most states, pre 68 I think. I don’t know what the laws are on modern artillery or when it was banned from private ownership, but I think it wasn’t till 1934, a century and a half after the second amendment. And I’m not sure they’re illegal now. I know there’s a Federal destructive device stamp which applies to artillery and shells, $200 each, so prohibitions are likely state. Buying one might be an issue, I don’t think the military sells them unless welded. And despite their legality, I’ve never heard of a crime committed with a legally obtained automatic weapon.
My understanding is that there was one murder committed by a legally owned class III Firearm...by a police officer in the 1970s killing his wife.
They had some small problems. Getting the MGs in the .30 Government/.30-40 Krag caliber that would use the same ammunition as the 1st Volunteer Cavalry's Krag carbines was not possible, so they settled for guns in the Spanish 7x57mm caliber instead, with only 4000 rounds of the Spanish caliber ammunition available to take with them...which turned out to work all right, after the Rough Riders Gatling Gun detatchment found an early 4th of July present in the form of about 10,000 rounds of Mauser ammunition in the Spanish trenches captured on July First.
As TR wrote in The Rough Riders (1899): "Our regiment had accumulated two rapid-fire Colt automatic guns, the gift of Stevens, Kane, Tiffany, and one or two others of the New York men … ." Most writers have since just referred to the Model 1895’s as "the Tiffany guns" supposing that the Tiffany mentioned by Roosevelt was Louis Comfort Tiffany, whose Oyster Bay estate, Laurel Hollow, was close to TR’s Sagamore Hill. They have also, mistakenly, referred to Louis Comfort Tiffany’s son William Tiffany, a trooper in the 1st U.S.V.
William Tiffany was actually the son of Newport, R.I., scions George and Isabella Tiffany, who donated one of the two guns to the regiment. He was promoted to sergeant commanding the two Colt-Browning machine gun section and was later promoted to lieutenant following his actions on July 1, 1898.