The only in depth comparison I ever attempted was the Python vs the model 27, and the answer was no difference in accuracy. Tailored hand loads would produce similar results...both extremely accurate, and pretty much the same with factory ammo. I've owned and shot just about very comparable model of Colt and S&W, and both will usually shoot beyond the capability of most shooters. The "super" accuracy attributed to some models is usually a biased preference from one individual. As with any man made product, there will always be a rare inaccurate "lemon" appear and that gun will get widespread attention.