I had to send my S&W 686 and my Colt Python back to the factory recently. For some reason, the rear of the barrels are rubbing against the fronts of the cylinders, to the point that they bind up. I guess the term for that is that the "flash gap" has become too small. My question is if anyone one knows why this is. I've been shooting some heavy .357 loads through them from a company called Armscor, but I don't know if this could have any effect. Thanks for your help.