I have several New Model Blackhawks, in several calibers including .357, and I just got a pair of 50th Anniversary Flattops that I gave my wife to use for cowboy shooting. Comparing the size and weight, they are very close, with the NMBH being slightly larger, both in frame size and grip frame size, than the Flattop, and 1 or 2 oz. heavier. I have large hands, and the grips of the Flattop are a little small for me. I am used to the NMBH and I like it. Grips are such a personal thing, you may feel more comfortable in your final selection if you can compare both.