You really need to work up your loads and using Alliants data or more conservative data is especially important when using a WSPM primers as its about the hottest pistol primer made and will drive pressures well beyond what you see if using CCI and other less potent primers.
Alliant listed 10.3grs of Blue Dot as max with a 158gr LSWC, Lyman lists 10.9grs with their 158gr RN #358311, 10.5 with the 155gr SWC #358156, and 10.8gr with the 150gr SWC #358477. As you can see 11.0grs would be at absolute maximum for a lead bullet.
Its best to use Alliants data as they're relatively conservative. A start load of 9.3 grs would be your 10% reduction. I'd load one box of 50 shells with 10 rounds at each of the following loadings (9.3, 9.6, 9.8, 10.0 and 10.2). Label and keep like charges together and head for the range. Shoot the rounds for accuracy and over the chrono if you have one going from start to max of course. STOP if pressure signs appear and pull any heavier loads. Check for leading after each batch too.
Approach 11.0grs at your own risk.
