How powerful is a .50 Deringer?

[NTMuzzleloader]

Does anyone know how powerful a .50 Deringer is, with a barrel length about 3”? I’ve searched for velocity data but can’t find any information about the Deringers.

 

[MrTom]

Probably not very powerful. That short barrel will have a lot of unburned powder fly out of it if a very heavy charge is used and the ball of fire that will result has the potential to be dangerous. Is it brass framed? If it is you probably don't want to load it heavy very many times. I think a patched round ball and maybe 15 grains of 3f black might be all the load you want to use.