Pressure with the above load was very mild, the casenecks didn't seal.  So I bumped up the kicker to 5.5gr, maintaining the same total of 52.2gr.  The 5.5/46.7gr did produce enough pressure to seal the neck.  I got to compare this load with a couple others you won't find in modern books.  52.2gr of both H4831SC and RL19.  As with the WW760 load above, both loads impacted significantly lower than the boosted 860 loads, but were about the same by weight and by volume.  It was also obvious by case and primer condition that both produced more pressure than the boosted 860.  Still no excessively flattened primers, no hard bolt uplift or extraction, no measurable solid casehead expansion.  I'm not interested in compressing either powder more than what I have.  I noticed some stringing with all three loads, down and to the right.  I found that my lower band had worked loose.  This is the rifle with the free floated barrel, so the band coming loose has a significant effect.  The stock has been sanded, I ran out of thread on the screw before the band was all the way tight, so I had to put a couple wraps of fine wire behind the the screwhead in order to get the band tight to the wood.  I'm loading the remaining brass with .2gr more booster and calling it as good as it gets.  So the next load I report on will be 5.7gr 10B101, 46.5gr of WC860.  It appears that this load is producing significantly higher velocities than the single based powders I have compared it to, yet less overall pressure.  At $69/8lbs vs the cost of 8lbs of commercial powder, I'm working with it!