Like I said I have not looked at the Ruger but have been told it is not all that strong as far as rifles go.
What you are looking for is an action with double under lugs, double bites and either a hidden third fastner or a Greener style, (preferably round) cross bolt. Even with these features you still want to check the proof marks and see if it will take the pressure and in all cases if using a shot gun action keep your chamberings to low pressure cartridges. A .375 H&H on a shot gun frame for example is not a smart way to go. My .450 # 2 is built on a French action and though it has double under lugs it is only single bite with a hidden fastener however it is a very massive bite and the 450 # 2 is very low pressure like 25,000 so it has worked out fine. If you figure out the pressure of the 450 compaired to the origional 16 gauge chambering and proof loads the 450 comes in well below the 16 ga. proof load. Even so you must always re proof the gun from some sort of a fixture where you aint holding it!!!