[Drdogface]

I never did that but not a bad idea, especially if the foam is too loose in the case.

To avoid any looseness of the foam disc I would slightly 'bell/expand' your disc cutting case to produce a slightly larger disc which will fit down into the case and on top of the powder charge snugly and not want to fall out.

What I ended up doing most often is only slightly different. Since BP will compress (and smokeless won't) I would put my powder charge of 2F black powder into the case and place a small wad of Kleenex or TP over the charge and compress it all with a dowel stick. The BP will compress into a lump and the tissue will prevent any grains/dust from spilling out. I doubt this will work with smokeless since it won't compress like BP.