N frame parts and L frame parts are not interchangeable, and parts are hand fitted at the factory. I have fitted a Model 29 with new a target hammer and trigger, but it takes a lot of patience and some very careful stoning to get it right. After taking it apart, stoning a few strokes, and putting it back togeather about a zillion times, it has a light, smooth, and glass crisp letoff. I enjoy working on them, but I'm not sure I really want to do it again. Be VERY careful with the stoning. One extra stroke where it shouldn't be and you'll have two paperweights that look just like a S&W hammer and trigger. Good luck!