Buschenmacher is the German word for gunmaker, and a Hofbuschenmacher is a semi-official title indicating approval from the city, or Hof, in which the gunmaker worked. I wish I could add more about H.Leue himself, but all I know is that he was in business from around 1900 to 1925.
The rifle barrel should have either a x.x mm mark, like 7,8 mm, or a gauge mark like 172/28 or 108/49. There may also be a date code of three or four digits like 1120 which would indicate a proof date of November, 1920.
Post a description of the marks on the rifle barrel, or better yet a picture, and we'll see what we can make of 'em.
