I have measured the width of the action on my 12 ga. BSS and compared it to almost every other American and European made 12 ga. S X S I have (quite a few) and the action width across the balls is the narrowest of any !2 ga. S X S I've ever measured. If they're overbuilt it is not in the action.
That's not where to measure them...
You can measure wherever you want to. Less mass, less weight, less potential strength.
Not the point...if you want to get a real idea of the size and mass of a SxS, you measure the action behind the fences.
I suspect the size of a shotgun frame behind the fences has very little to do with a gun going off the face. And for some reason, my Physics professor never taught us to measure the mass of an object with machined internal voids by using something like a tape measure or caliper. Total mass of a shotgun frame could be quite substantial, yet still yield upon firing if it had poor design in critical areas.
Simply measuring the mass of an action, or the width behind the fences totally neglects very important factors like cross sectional area at the point of greatest stress, and/or the alloy and heat treatment of the steel.
We had a good discussion about this awhile back in one of the Ithaca Flues frame cracking Threads, along with an FEA analysis that Boxall & Edminston engineers did to illustrate the point of greatest stress upon firing with one of their frames. Hint: It wasn't behind the fences:
https://www.doublegunshop.com/forum...;Words=Boxall&Search=true#Post636161
