Metal reinforced stocks

Are these well known or have I only just noticed ?

The Sako A7 roughtech seems to have a frame inside from some sort of ally bedding block down to the butt. (Not talking about full alum chassis rifles like the AI and TRG, nor pillar bedding or a block the length of the action). The Savage Accustock just seems to reinforce the forend.

This seems to add about 500g to the weight of the A7 compared to standard stock - is it worth it ?

What other rifles use a similar system and is there any consensus whether it helps ?

Isn't it just a Bell and Carlson and they have been doing it for years...

HS precision did that for even longer and it is still the foundation of their stocks.

Choate tool as well on there varmint and tactical stocks.

Bad and heavy; imo.