Hello:
Stumbled onto two fascinating YOUTUBE video's of what appears to be a French craftsman demonstrating his fully functional and firing scale model.
To view, simply search for "1/4 scale Spencer Carbine".
That method of access worked several times.
There are minor mechanical aspects related to the center-fire striker, barrel-to-frame joint and a (genius) wedge above the cartridge feed guide spring for perhaps cycling tuning.
Hopefully SSS members will see more that is remarkable and post here.
All the best,
El Supremo/Kevin Tinny