It could very well be that the hammer is not recocking. I had a BSS that did the same thing. Took it to Jim Kelly and he fixed it. Never has happened again, and I'm still shooting the same gun many years later at ducks and clays.

Probably not something you want to tackle yourself, as there are two or three things that can cause it, and experience fixing doubles is the best teacher as to how to best fix it.

SRH

May God bless America and those who defend her.