Joe, it looks like you ground the lip off a bit. Was it so the extractor would lift the empty hull?
I have Chambermates Silver 12 to 20, so there is no split. I don't load 20s so I don't why they couldn't be reloaded seeing as how it doesn't have the split. They are made without the split when you jump two gauges.
My experience with the 12 to 20 is that the pattern is about 1" larger. I don't count pellets; just the effective size of the pattern; lazy
I wonder how much pressure drops using 12 to 20 or velocity change?
