Third, Results.
50 yards.  Three feet of snow.  Took half a dozen trips with the snow shoes on to pank down the snow so I could see the target burm.
https://i.imgur.com/NYIgugK.jpg

https://i.imgur.com/HMXxhHz.jpg

So there you have it.  I went from 13.3 3N37 up to 13.8 3N38.  Placed some white paper tablecloth stuff in front of the bench and saw no detectable un burnt powder.   The action did not cycle and had to hand eject each case.  I think (hope) the suppressor will add a little more back pressure.  Running the lightest buffer I could find now.  May try trimming some coils off the buffer spring or lightening the bolt carrier.  Stay tuned for further revolting developments.