Winchester 231

I need a starting point for reloading with 185gn zero HPSWC's and Magnus 185's. I am out of BE powder but have a couple of pounds of the 231 I'd like to try. Thanks, Bob

4.5 Gr 231 works for me
Frame mounted scope
13# progressive spring

I bought an 8 lb keg of HP-38 which is suppose to be the same powder with different label as W-231.  At 72 degrees F the velocity from my Springfield/Kart with a 200 gr. H&G 68 style cast bullet were:

4.4 grains  716 fps
4.6 grains  737 fps
4.8 grains  771 fps
5.0 grains  805 fps

My best group from sandbags at 50 yards was 4.3" group for a 20-shot group with the 4.8 grain load at 771 fps.  For comparison sake,
this pistol shot and average of 2.75" at 50 yards with 3.8 of Bullseye for (3) 10-shot groups with a Ransom Rest at 50 yards.  Not sure what the difference would be from R.R. groups to sandbags for me?  I would expect the loads in a R.R. to shoot similar to the 10-shot Bullseye groups.

With your 185's, I would try 4.6 to 4.8 grains of W231 for starters.

Good Shooting,  Steve

My 4.5 gr load with H&G 68 200-gr gives about 725 fps.

5.1 goes about 825

and 5.4 went 848 last I checked it, okay for "major" in those grab and go games.

Since Hornady 200-gr XTPs are still grouping better with the two heavier loads, I'm going to be more careful and inspect more closely next time I cast up a bunch of the lead ones.

The starting point is ALWAYS the starting load listed in the manual.
Personally, I check at least three different manuals and always start with the lowest starting load.
I haven't had much luck with 185gn cast or swaged bullets, but here are some loads that were at least OK:
Bull-X 185gn L-SWC and 6.0gn Unique
Mastercastbullets.com H&G 130 185gn L-BNWC and 4.1gn 231/HP38 or 3.7gn Clays
Precision 185gn L-SWC "Black Bullet" and 4.1-5.1gn 231/HP38 or 4.4gn AA2 or 6.7-7/1gn AA5 or 3.5-3.7gn Clays or 4.0-4.4gn N310 or 3.9-4.6gn Red Dot.
Zero 185gn L-SWCHP and 5.2gn 231/HP38 or 3.3-4.8gn AA2, or 3.8gn N310 or 4.1gn Red Dot or 4.0gn and 5.0gn Solo 1000, or 4.3-4.4gn WST.
The Precision was the best, with the Zero a close second.