I know a few guys who do. Absolutely no ill effects other than the typical heavy load issues youd have with any SxS shooting loads like that on a consistent basis....the only issue being the gun will eventually go off the face. It might take literally decades of heavy use for that to happen. Make sure the chokes are open enough (nothing tighter that .020), make sure your draw bolt is nice & snug. Thats about it. Lots of guys out there shooting Citoris, SKBs, Nikkos, Mirokus, 101s, (lots of those are the same gun I know) etc from the BSS era with zero ill effects.
I myself use a late 80s early 90s SKB O/U with steel. It digest a lot of heavy 1 1/4 Oz loads with ease.
