File:Trapdoor Springfield.png

Summary
The Allin/Silva is a copy of the Trapdoor Springfield. https://en.wikipedia.org/wiki/Springfield_Model_1873#/media/File:Springfield_%22Trapdoor%22.jpg is a US Government photo in Public Domain see https://en.wikipedia.org/wiki/Springfield_Model_1873#/media/File:Springfield_%22Trapdoor%22.jpg