One of the big things about WW231 in a big case, is that the powder is not coated or treated in any way. It is the raw material all of the "ball" powders made by Olin use. So it is not position sensitive, very easy to ignite and very consistent from lot to lot. The only residue is the graphite blended in to make it run through automatic machines (the only difference between it and the older 230P) and any unconsumed carbon.
Hmm. Have you bought any recently? Reason I ask is the "old" stuff, ca. 1990s, is different in both appearance and performance than the newer stuff. I have a bottle of HP-38 and several bottles of WW231 made in the last 10-15 years and as near as I can tell the contents are identical other than lot numbers. Compared to the keg of WW231 I had before that, all the more recent production powder is much glossier, leaves a lot more carbon for the same load, and burns a lot less consistently when loaded to equivalent velocities in .38 Spl, .45 ACP, and .45 Colt. A few years ago I did some chronograph work with the newer powders because I my old keg was near empty. I wanted to see if the Hodgdon and Winchester stuff was indeed exactly the same product as I had read, and also wanted to make sure my "pet" loads were still going to work just as well with the new powder. I have to say I was very, very disappointed. The new stuff exhibited position sensitivity in the extreme in both the revolver cartridges, and I never could get it to group as well in my .45 autos as the old stuff. I did several back-and-forth comparisons between HP-38 (one lot), WW231 (two lots), and my old lot of WW231 to check velocities, SD, and groups, finding position sensitivity and group dispersion to be very unfavorable with all the new powders. Average velocity, as I recall, wasn't much different between all of them, less or equal to the usual +/- 5%, but the SD numbers did not impress favorably.
Needless to say I was extremely disappointed since 231 is a great midrange handgun powder and is absolutely ideal for heavy .38 loads and .45 Autos using 220-230 cast loads, or maximum-level 200 grain loads. What I ended up doing was switching to IMR PB and had better results after re-working loads for all three cartridges. Then, naturally, IMR discontinued that powder during one of the great shortages and I didn't have a chance to stock up, so here it is 2018 an I'm still looking for a good replacement for 231.
