Administrative results has a nice video on the Ferguson rifle, and I have to admit, the gas seal was better then I expected. I hope someday Capnball (A great Hungarian youtube channel that concentrates on historical firearms that are recreated with extreme attention to detail) geta hold of one of these, I'd love to see him do a mad minute using authentic paper cartridges for this gun, Administrative results was loading from a flask and ball pouch which slowed him down a lot. It also made prone loading very problematic, although I'm unconvinced that it was all that much better then a short muzzleloader for loading prone. Still a interesting early breechloader that was specifically designed to be a robust useful military weapon designed by a veteran soldier.
https://www.youtube.com/watch?v=9mTIk7Jd23g&t=783s