Hoptob, have you thought about Ramshot's Silhouette? It's a duplicate of WAP, and the Ramshot load data lists (from a 7.75" barrel) a 158 gr SWC getting 1046fps over 5.6gr at 16,720psi. It's also flash suppressed. It's right below HS-6 on Ramshot's burn rate chart, too.

Great photo essay and test! Thank you!