So, I had it out again today. I shot 2 1/2" 1oz 7 1/2s loaded by RST. That's right, smokeless!
http://www.rstshells.com/store/m/3-16-Gauge.aspx
RST loads smokeless short-chamber shells at low pressures specifically for old doubles. I have to admit I fired two before I wrapped my hands around the barrels while shooting. No troubles at all. I'm comfortable shooting these in this gun. Make your own decisions about your own guns.
Unlike my BP loads, these are made up with modern shot cup wads. I'm pretty sure that the heavy fiber wads in the BP loads are punching holes in the middle of my patterns. I couldn't quite decide where to hold to make consistent hits with the BP shells.
Night and day difference shooting these. I was powdering everything I shot even close to. I missed two shots of fifty and one of them was me chasing after someone else's miss like a smart ass. Maybe I don't suck at this after all.