Is there enough room under the barrel to mill a slot and epoxy in some steel rod? This would add weight in the right place and stiffen the fore end as well.

I have an 8 1/2 pound pre64 M70 with a McMillan stock that is great to carry and Ok to shoot.

It also been MagnaPorted ... which doesn't really reduce recoil but does reduce muzzle rise (flip) and I think that's what's bugging you. Be warned, MagnaPorting does make the rifle louder for those near you. Never bothered me in the field but has been comment upon by folks at the range.

Get it Magna-Ported.
I have a 300 Win Mag and a 375 H&H bbls for my Blaser R 93, both Magna-Ported. Made a difference in the felt recoil. They do not seem any louder to the shooter as far as I can tell.