There is a lot of good information here about black powder and brass shells.
http://www.tbullock.com/bpsg.html

Track of the Wolf sells this reproduction dipper

http://www.trackofthewolf.com/(S(ghxtt02...m=SHOT-DIPPER-D


I have picked up several originals over the years on ebay. You want an adjustable one. You can make them yourself for set volumes.

Pete