@ Vespers War.
Here's one that may interest you (assuming you don't already know about it!), the Faucon Fusil Équilibré or in English, the Faucon Balanced Rifle.
https://www.historicalfirearms.info/...tenant-colonel
https://www.all4shooters.com/en/shoo...rifle-designs/
Brief mentions in these articles: -
https://armourersbench.com/tag/francis-bannerman/
https://www.smallarmsreview.com/disp...darticles=1822
And just to pique people's interests, a picture of the beastie in question...