[Unclenick]

I would treat those Ranier FP's the same as a SWC shape. The usual routine with the SWC shapes it to get the shoulder where the ogive angle starts away from the bearing surface about 0.020" (about a thumbnail's thickness) north of the case mouth as a general purpose seating depth that should fit any gun. That's a starting point. If your gun will feed them, you can adjust the seating out longer until the bullet stops on the throat of the barrel when the back of the case is flush with the back of the barrel. That's called headspacing on the bullet, and with lead bullets that gives me best accuracy. As much as 40% tighter than the standard 0.020" out approach, so it's a big difference and not a small one. I haven't tried it with plated bullets, but presume something similar will happen as they are not hard like jacketed bullets. Jacketed bullets don't seem to care which way you seat them.

With the charges I mentioned you should be able to handle small seating depth variations without risk. If you are uncertain, you can always back down more. I used to shoot 3.8 grains of Bullseye under 185 grain cast lead SWC's that weight for 50 foot gallery and 25 yard timed and rapid fire. I've shot the Goldcup with reduced power recoil springs with as little as 3.5 grains, but the accuracy was significantly poorer. The most accurate load was the no longer available 200 grain Hornady JSWC over 4.2 grains of Bullseye (Win brass, Fed 150 primer). I've previously posted my Goldcup's 0.37" CTC 5-shot 25 yard group fired off sandbags using that load. That load shot 50 yard slow fire targets very well.

I find 231/HP38 loads need to be about 5% heavier than Bullseye loads to stay in the same pressure and velocity range, but YMMV with your primer choice. I was using Federal 150's for the most part. So I would multiply the above mentioned Bullseye loads by 1.05 to get the adjustment. Accuracy testing should tell you what you want to end up with.