An update for anyone who's interested... I dismantled the Sako and found the glass bedding under barrel hadn't been sanded very well and more importantly, the fore end sling swivel screw was pushing up the bedding to be in obvious contact with the barrel (Spot on @Bill999 ) I suspect this was the primary cause for 'rise'. So I've sanded it flat and all looks good.
The barrel was filthy too and a surprising amount if copper (and brass filings!) were removed to produce a respectable looking bore, so a huge improvement.
I haven't had the chance to shoot her yet, but will update with a photo of grouping once done.
Cheers
Bookmarks