"I bought a box of 500 cast lead 200 gr swc bullets, and I was wondering if you had experience with cast bullets. I loaded some last night with 4 grns of Red Dot powder, as it was the only powder I had that I could find cast bullet data for. They were very mild in report and recoil, which I liked."
I like Winchester 231 so much that I've gone to buying only 8lb kegs. I realize that there are other new powders out there that claim better fps. BUT and this is important, 231 burns clean without a lot of smoke. That is my number 1 reason for shooting it. Number 2 reason is that lead fouls and I prefer a powder that doesn't melt half the bullet onto my barrel. Now the Red, Green, and Blue dot powders do burn a tad colder but they are dirty and smoke a bunch. When I'm shooting a lot of 45 acp I like to be able to see the targets without waiting between reloads.
When I load 45 acp with 230 grain lead cast, I've experimented from 4.7 grains up to 6.2 grains in 4 and 5 inch barrels. If you go under 4.7 grains of 231, you can get incomplete cycling of your action AND although its never happened to me, you can get a cast bullet stuck in the pipe. I think the reason for the obstructed barrel has more to do with the stickiness of lead than actual bullet velocity.
I normally use 5.0 grains of 231. I'm getting about 789 fps with 230 grain bullets, 4in barrel. This brings us to reason I like 231 number 3, this a cheap load to shoot. 5 grains is nothing in terms of cost, and brass lasts 6 or more reloads. I've played around and got over 12 reloads with this recipe. I'm guessing that your semi-wad cutters will like this just fine. So start at 5 grains and see how your gun likes it, you can always adjust up or down. Leading isn't too bad. The reason I went with 5 grains instead of 4.9 or 5.1 etc was the standard deviation was tighter at 5. Let me know how it works.
Winchester's 2003 reload manual lists 5.1 grains of 231 as max load for 230 grain cast bullets, and 4.5 as the min for 230 lrn. 200gn lswc is listed as 4.8 to 5.5 grn of WIN 231, getting 800fps to 910fps.