I loaded a few brass 12 gauge shells last week and took them out to use on squirrels from my old Diamond Arms single barrel shotgun. I call it Grandpa's shotgun since it is identical to the one my Grandmother gave me after my Grandfather passed away. My house burned in 1968 and so did Grandpa's shotgun. I've been looking for one like it ever since, found this one only a couple of years ago.
I don't normally shoot squirrels with a shotgun but this was a nostalgia thing and I was able to keep all the shot in the heads by passing up all shots except those where only the head was showing. Grandpa wasn't as picky so I have lots of childhood memories of biting down on #6 shot.
Anyway, I loaded 3 drams of Swiss 3f, card wad, dry felt wads to take up space and as a cushion, another card wad under the shot, right at 1 ounce, maybe just a hair over, of shot with an over shot card wad sealed over with carpenter's wood glue. I have some old hand reloading tools I found in a box of junk I bought at an estate sale some years back which work well with the brass cases. After the cases are fired, there is a little of the hardened glue still adhering inside the case mouth so I imagine it sticks pretty well. I'd try them in a double without any fear of the over shot wads coming off under recoil. Sounds like a test is needed, tkendrick. Load up your double, fire one barrel over and over without ever shooting the other barrel. See if you can MAKE it happen. If it does happen from time to time, even then I'd still probably use them, those brass shells are just cool!
What I need to try now is some of those loads without the cushion wads.
Steve