I just had the delightful experience of speaking with Chris at RST. She gave me some average pressure specs for their 2 1/2" 16 gauge shells. They have plenty of choices that are safe in old guns and Damascus barrels in good condition.
Their Ultra Lite 3/4oz load boils up to only 5,200 PSI on average. She says that all but the 16ga 2 1/2" ammo for semi-automatics (Browning A-5s) has low enough pressures. I'm sticking with the ultra lites and the 1125 fps 7/8oz paper hull loads for the Damascus barreled drilling coming as a safety margin. It'll get me out harassing dove and quail.
https://rstshells.americommerce.com/store/m/3-16-Gauge.aspx
