Thank you all for your inputs. To elaborate on some of your recommendations:
Checked scope base, rings, pic rail. All seemed OK, except TPS clamp ring nuts were not loose, more than finger tight, but not as tight as tight as they should be. Tightened.
Disassembled stock, cleaned mounting surfaces, retorqued to 30in-lb, and will retorque rear as a I shoot again.
Use Hornaday device to measure to lands, and set jump from that number.
Use Wilson seater---so runout should not be issue.
Neck size with Forster shoulder bump sizer with .337 bushing.
Leupold 8-25 Varmint scope, TPS rings, picatinny 4 screw base. Reseated ring bolts up against rear surface of pic notches.
Primer pockets reamed, flash holes chamfered, Lapua brass, Thumler cleaned.

Went to range yesterday, but turned around and went home. TOO many AR-15 Walmartians that got guns for Christmas.

Next step:
Shoot 6 groups of 5-B155VLD loaded from -.002 to -.020 with Varget 46.0g-3050fps to see if those scope rings were the issue.
I am thinking that I am pushing my load too far, based on comments on blog plus friend who says to get down to 2800fps--away from max. I thought speed was good, but he says not always? Going to go back to 44.0g start load, 44.5, 45.0. 45.5, 46.0--------got thru sequence again, and refresh conclusions.

Might also explore Winchester 760 powder again.
Might also try 150g bullets again. Someone told me I would do better with 155g, but was doing reasonably well before I switched. Suspicious of my 1:13 twist 30" bbl.

Have to figure this out before I go insane.

Not usually a forum type, but appreciate your thoughts.