4seventy

No heat transfer is a big advantage here - together with the independance of the barrels due the under barrel "free floating" thus the growing of the barrel when shot will not affect the POI and regulation of the single barrels - this gives very good results for successive shooting - otherwise the barrels would drift apart as in soldered barrel sets....

You may be right with the 12 gauge frame.

Maybe what I found was related to using very light and fast bullets for the 9,3x74r? Didn't check the 286grn in this rifle.

Cheers, Franz