The Stanley Bull-Dog revolver is an English-production revolver which is marked as being "Hill's Patent". The gun uses an interesting simultaneous ejection system similar to the Fagnus - which one would assume was the subject of Hill's aforementioned patent. The guns were made in a variety of configurations (blue, nickeled, various barrel lengths and calibers, etc).

Hill's actual patent (number 3645 of 1878) is actually a provisional patent relating to the lockwork that turns the cylinder. In fact, the ejection system used on the guns was invented by a Belgian named Jean Mathieu Deprez-Joassart five years earlier in 1873. Deprez-Joassart did patent the mechanism, and Hill appears to have simply claimed the system as his own and convinced a British gunmaker to pay him royalties for guns made with it.

Thanks to Select Fire Weaponry of Waukesha, Wisconsin for loaning me this revolver to film.

Thanks also to Littleton.Be for use of photos of Deprez-Joassart revolvers - you can see their whole page on the man here:

https://littlegun.be/arme%20belge/artisans%20identifies%20den/a%20deprez%20joassart%20gb.htm