Nope, never heard of it done. Not sure the 66 is up to the challenge. Maybe 40, but I would say definitely no on the 10mm. There is a guy, Dave Clements I believe, that converts Ruger GP-100's over to 10mm. Nice finished product, but the conversion starts out around $600. For the cost of the GP and the conversion you could have a new S&W 610 and a trigger job.