due to problem with my hands {old age} i want to reload 357 brass to 38 sp. power. want to avoid crud ring. i know i should adjust powder for the larger case but by what amount. any ideas? thanks.
I do this for a couple bullets, all lead, BTW.
I use Red Dot with extruded lead bullets, and it has worked fine for decades. I avoid reducing loads for jacketed stuff, as it's a good way to stick a bullet in the bore. Red Dot is very economical for this type of load with 140gr -158gr lead stuff. I load them to about 800fps, both bullets, and they work real well. I use the Hornady swaged and the Remington bulk swaged for these loads. Both bullets will have a sweet spot between 3.5 and 4.5gr, you just have to find it. I have a 3" M36, a 2" M637, an SP 101, and a 4 5/8" BH. Sadly, they all have a different sweet spot with any bullet.
Most cast bullets need more zip, unless you get an alloy for lower speeds. Penn cast bullets have that option in several sizes, including a 125gr bullet that can be loaded way down for sore hands or beginning shooters.