Head space was excessive. Now snug. Bore is large, .375/.381 grooves. Did the Beagle thing on the mold. Still making shotgun patterns at 50 yards with the 375248. Tried variety of powders, no progress. Noted a suspicious muzzle flaw on one land. Did the ball grinder followed with the 400 grit polishing. VIOLA. NOW I can work on refining the loads with some hope of more improvement!!!!!