Burch
If you can find a factory load that produces pressures compatible with your gun, you CAN shoot them in your gun. The issue is more one of finding pressure data on a factory load. I've called Federal and asked about pressure for a particular load. They were not evasive, but only provided that "... they liked to keep the pressure around xxxx." Others here have cautioned that pressures may vary greatly for a load since only the velocity is 'promised' on the load and powders are sourced from the cheapest supplier. I would challenge that claim on a premium shell like the STS and AA and possibly other better lines. I haven't seen any convincing evidence of that activity by the ammo makers.
But, just the same, I'd recommend you poke around in the premium target ammo lines and find something that looks promising on the pressure and send it to Tom Armbrust for testing.
Frankly, though, I've found it easier to load for just the specialty ammo for my damascus guns and buy factory ammo for the modern guns. Currently, I have only one setup for 12g damascus guns, the load I mentioned above. I find it simplifies life a bit to just change the shot size for the different types of bird hunting. Sure, I could go down to 7/8 oz for the dove/quail load and back to the 1 oz or maybe even 1 1/8 oz for the pheasant load. But I have found it makes little real difference in the end.
