CG80 were converted to .308 win (actually, to 7.62X51) but they have some modifications on the bolt gas escape ports and often a hole added in the front action ring, plus a veeeeery long throat (a long engaging cone - and so does most of the sporting M/94/96/38, made by HVA or iothers). Just the cone by itself is enough to lower the pressure several thousand pound square inches.
Kimber also made a run of '94/96/38 in many chamberings, and quite a few of them had problems.
Saying it's no worse than a Winchester is forgetting that the Winchester are made of modern alloy (Cro-Mo Steel), not 1020, so the steel by itself have a much higher tensile strenght. But, yes, it's about true to say that the old 70 does not handle gases that well.
And, as I pointed out above, I don't say it's a bad action or anything, I just say it was not designed in the same period than the high power calibers, so unlike the '98, it was not designed with that in mind. But honestly, I don't see why one would use such an action to build a "modern pressure firearm" when there are so many good action readily available for not so much money....