When I built guns from Mausers, I used PAWS aluminum floor plate assys. They were much lighter. I even made a couple with blind magazines.....this too was quite a bit lighter than even the PAWS aluminum.

Now I'm using post 64 M-70 actions and want to know if there is a source for light weight bottom metal.

I use #1 contour barrels but need to find further ways of weight reduction. Any advice out there?

Most/all post 64 M70s had aluminum floorplates and TGs until I don't know when; you could look for those.
But M70s are probably not the action one should be using if looking for truly lightweight rifles. They inherently carry a lot of weight that the tubular receivers don't have.

You can always do it as a blind magazine. That's what I did for a couple that guys were wanting as light as I could go on their existing M 70's. With 24" barrels I think they were still about 6# with optics if I remember right.

D'Arcy Echols makes aluminum bottom metal, Sunny Hill makes aluminum bottom metal, and PT&G makes aluminum bottom metal.