I have an old 77 (not Mk II) 6mm that was my late fathers. Always a problem child being a 1.5" 3 shot 100yd gun at best, I took it to a gun smith friend who floated the barrel and glass bedded the very nice walnut stock.What a difference!
I only wish I would have done this for my dad 30yrs ago, he just didn't want to take a chance with someone messing his pretty little 6mm up.