I understand that you can't always mess with wad column in shot shells but is the following safe?
Because I have the crappy gas seal from bpi, could I add a hard card under it for a better seal? Is it safe to use a filler or corn meal or cream of wheat under the wad? Doesnt 410 shells have filler in them? Loose filler that is. Also why is it that the wads I have require building the shot column in a 2.75" shell? When wads in 12ga don't?