These five riflemen of the early 20th century are responsible for much of the development of high-velocity rifles and ammunition. In 1908, using a Niedner barrel, Mann fired the first shot ever from a 220 Swift. (Well almost; it was a 6mm Lee necked to 22.) Mann had pressure problems due to lack of suitable powders, and didn't develop it further.

There's a 13-page thread about this photo over on Doublegunshop.com: Link to Thread

Mike Petrov, who posts here, owns (owned?) the rifle held by Dr. Mann; I think he's shot it and reported on its accuracy.
--Bob