Took my new Model 63 to the range for the first time. Shot perfectly the first 60 or so rounds. Then, suddenly, with one unfired round left in the chamber, the cylinder would not rotate. I removed the ctg and gently de-cocked and re-cocked the gun. The cylinder rotated normally again. Then, again, with the eight pull of the trigger, the cylinder would not rotate. Did the de-cocking/re-cocking routine several more times with the gun unloaded. Same result: the cylinder was fine through the first seven cocks of the trigger, but would freeze up on the eight pull. Needless to say, this is very disappointing. Before phoning S&W, I thought I'd ask the savvy forum members here for their opinions as to what the heck is going on with this revolver. (As you can tell, I'm a newbie with much to learn.) Many thanks in advance to all who take time to reply.