I checked with PRVI before using the cases, I know that here in the US we used sub par cases to make blanks.  These were newly made, and I did a lot of measuring, weighing and comparing, without sectioning any though. The only difference in these cases was the amount of polish and the neck/shoulder area needed annealed.  As far as the charges go, I worked up with the booster.  A lot of fellows on castboollits use the boosted powder for cast loads, and others there have experimented with jacketed.  The boost makes up for the difference in primer fire, 50BMG primer vs LRM primer. The 50BMG looks to be about 4x larger.   One could think of the little charge being similar to the charge behind a 200gr bullet in the 44 special, since the case is the same diameter and the weight of the 860 plus 150gr bullet above is close to 200gr.  So the near 200gr powder/bullet column gets a little push down the barrel before the 860 really starts to burn.  Burn rate of the whole, judging by the POI change between loads using other slow burning powders is between H4831SC and RL19.  When I had access to a chronograph the SD of loads I was testing at that time was very low, very consistent, and they were usually pretty accurate loads.  I'll let you all know if I hurt any of my rifles, like I did when I managed to ring the chamber neck on one!