How in the world are those rifles made that light?
The late master stockmaker Dale W. Goens had several techniques he used in creating his famous mountain rifle design. He first would select English walnut stock blanks based upon not only grain structure and figure, but wood density per cubic foot weight. He would shape a very slender stock profile, then route the barrel channel and the butt of the stock under the recoil pad to reduce weight.
The action would be a small ring Mauser, usually a G33/40 to ensure the lightest receiver possible. The magazine well was drilled with perforations (Called Swiss Cheesing) and the bottom metal would be custom shaped and contoured. Usually, a Douglas featherweight barrel of 22" length would be used for additional weight savings. My Goens mountain rifle has a Timney sportsman trigger made of Aluminum alloy and was probably the lightest available at the time.
Needless to say, a few ounces here and there, they start to add up in the final product. There is a great article by James Olt on these mountain rifle features in the 1976 Gun Digest, 30th Anniversary Addition, if you have access to it. If someone would post pictures for me, I can display with photos these features here on the forum.