Someone had butchered the trigger on that Seneca. The un-set pull was so light that the hammer didn't want to stay back.
I wound up coming home with a Lyman GPR .50 percussion instead. I don't like it but it's the least bad on the short list of options still available it seems.
Got buyers remorse with the GPR. If I still have $$ left after Christmas shopping is done I may buy the Seneca anyway and try to revive it.
Tom