The Johann Christian Oerter rifle.   (FBI via LeHigh Valley Live)

The Johann Christian Oerter rifle, made in 1775, was stolen from Pennsylvania’s Valley Forge visitor center in 1971. It took five decades, but now the man who took it has pleaded guilty in the case, the New York Times reports. Thomas Gavin, 78, will be sentenced Nov. 15; he faces up to 10 years behind bars for one count of disposing of an object of cultural heritage stolen from a museum. In 2018, he sold the rifle and more than 20 other antique firearms to a Pennsylvania antiques dealer for $27,150, and that dealer realized the following year that the weapon was stolen after reading about the theft in a book. A crowbar was used to pry open the rifle’s case in broad daylight; a Boy Scout noticed the missing weapon later. Prosecutors have not said what length of sentence they are recommending, but said Gavin should be ordered to pay no more than $20,000 in restitution. An antique firearms expert says the rifle’s market value is $175,000. Gavin also confessed to stealing 18th- and 19th-century firearms from the American Swedish Historical Museum, the Valley Forge Historical Society, the Pennsylvania Farm Museum, and the Hershey Museum, according to his plea agreement.