Re: Chassis for TRG's
I shoot a TRG 22 para and there isn't really any way to change out the standard stock on a TRG, except perhaps to go to the Sako folder.
You could probably custom make something from billet aluminum or alter the existing stock by building it up with fiberglass or similar. But the TRG uses a huge alumimum pillar with a stock that is just a shell attached to the structure.
FYI, the TRG's are designed from the ground up for sniping and isn't really designed to be customizable. The Finns got it right from the factory. And TRG's are so limited production that noone makes much in the way of aftermarket for them.
If the stock is that far off for you, your best bet may be to sell or trade your Sako for a platform that you can make exactly as you like. Even used, the Sako's are expensive. But you will be hard pressed to build a rifle as accurate as the Sako is out of the box.
Good luck with your research and hope this helps. SIRHR