From my gunsmith (I have my grandfathers double--same vintage): don't even think about it(I know you're not). The old black powder shot shells were shorter and were sealed with a cardboard disk-- when fired the disk blew out but the tube hardly elongated. Modern shot shells use a crimped in a closure that opens up and effectively elongates the tube. Modern chambers are long enough for this effect. Your gun has short chambers and a modern shot shell will effectively reduce the bore size, restricting the wad/load and increasing pressure dangerously when fired. My GS had a customer who had a similar double and liked to load BP in modern shot shells to shoot it. Kaboom! Blew out a chamber, lost a finger, and his career. (He was a dentist).
On restoration-- he said only cold process refinishing could be used on these guns. Hot blueing will release the solder joint that holds the barrels and center rib together giving you 3 loose pieces-- 2 barrels and a center rib.
My gun has no historical value but lots of sentimental value. My gunsmith cut off the firing pin tips with a dremel cut-off wheel and I hung my double over my mantel.
I know this is way more than you asked for, but it is so similar to my gun I thought I would share.
Enjoy grandpa's gun!