Afternnoon 1Longbow,
I have a thing about barrel pressure, have for YEARS, so years back I started glas bedding and floating any #1s which come my way.
With the under barrel hanger, you bed to the part where the forend screw attaches, and a couple places - one on each side - back toward the action.
Then you float as normal.
This does away with barrel pressure issues, as the forend is now tight to the under barrel hanger and the two other spots - one of which is the post where the ejector spring adjustment is located - and not touching the barrel at all.
When I say I bed to the under barrel hanger, I do not mean I bed to the full length of the hanger, but rather just to the nose portion where the forend screw attaches.
If your vertical stringing is a barrel pressure related issue, this should take care of it.
Keep em coming!
CDOC