If you can find a copy, Don Getz recommended this article years ago.
"Lancaster Rifle Accessories" by Henry & George Landis located in the Pennsylvania German Folklore Society Vol IX of 1944. The article covers early Progress of rifle design, types of early rifles, decoration, hunter's equipment, and Lancaster pistols.
The Landis brothers were curators of the Landis Valley Museum in Lancaster, now the Landis Valley Village & Farm Museum. The Pennsylvania State's Museum of Pennsylvania German History, Heritage, Lifeways and Farming.