My experience with cast bullets (boolits to those that frequent another site!):

Too soft and too small driven too light is a bad thing.
Too soft and is the right size or bigger, drive it like you stole it under 1300fps.
Too hard and too small driven too light is a bad thing.
Too hard and is the right size or bigger, drive it like you stole it over 1600fps. To clarify one point, after 1600fps, in my Marlin 1894 and accuracy begins to suffer drastically.

All of the above is without gas checks. I get virtually no leading. A flake here or there but usually gone with 2 wet patches.

What you need to do is determine your cylinder throat size and go from there. It is that size and bullet fit that will determine how successful you are with lead bullets (boolits ) in your particular firearm.

The old 7-9gr load of Unique under a Keith style LSWC is a good load. His load of 2400 will work in some firearms. Just make sure you work up to it. 2400 is much more forgiving on lighter loads than other "magnum" powders.

To be honest though, with the right fit and hardness, your revolver should be able to turn out some 1300fps 240-250gr loads with not too much problem.

I am using a full charge of H110/W296 in my M629 Classic with a 5" barrel. I have gotten consistently more than 1300fps from it with this load.

Remember one thing; start low and work up. With H110/W296 there is a limit on how low you can go. Make sure you check current data before loading anything.

Hope this helps!