I shoot 7/8 oz 6000 PSI handloads for targets and nickle plated shot full boogie factory loads for pheasants!
For waterfowl I load moderate pressure short ten's with Nice Shot and shoot factory Kent Impact and Bismuth in 12 gauge.
I have used factory "promotional" 12 gauge rounds in 10 gauge Damascus with gauge mates with great success. The larger bore (11% surface area) will allow more room for the pressure to expand and produce somewhat less peak pressure. I'd shoot the same in a fluid steel Parker 10 gauge if I could ever find one within my limited price range...
The bottom line for me is for everyday shooting I keep the pressure and recoil low in 100+ year old guns. But for a few dozen shots at game each season I trust my Parkers (which are in good condition and have appropriate Minimum Barrel Wall Thickness) to safely shoot factory loads.
PS: If you do not handload I suggest visiting someone who does to watch and help. You might make a new friend and discover how fasinating loading your own ammo can be!!!
Mark