16 Gauge Vulcan, 1 Frame 28 inch barrels choked m,f

[edgarspencer]

I'd love to hear what your Metallurgist friend has to say about how badly this 'fluid steel' has aged. I only have a masters in Applied Metallurgy, so all I know is it's only "Fluid", going from furnace to mold. After that, it's just steel.
Given your gun is a one frame 28", you're not going duck hunting, and any pheasant and upland load appropriate is going to be easily digested.
Copper plated shot shot reacts much the same as the un-plated lead, and has no deleterious effect on the barrels. The whole point of keeping loads reasonable, getting that lead moving no faster than it needs to be going, is to reduce recoil on the 100 year old wood. Anything you think you need 1 1/8 ozs for, will be equally well accomplished with 7/8 to 1oz. 1175-1200 fps loads are unlikely to damage your 'aged, fluid steel' barrels.