General rule; felt or spacers under shot reduce pressure, spacers over shot would increase pressure. This has been discussed by a few guys who reload and test.
the load I talk about is build with the fiber wad under the cup wad because , it gets the brass base from swelling to the point it will not eject . I have not pattern it or chronograph to date but I have ordered a chronograph before I waste another $ 10.00 shot . I seen no hesitation in the load and the piece of 3/8 '' foam should not change the pattern and the foam is light enough it should not effect it. Their is no wad inside the cup wad it is behind it . I just yesterday dissect factory shells that only had two fiber wad and a wrap .
There’s only a couple lead loads for 2” hull in BPI’s most recent Small Bore Manual. Not a ton of data!
What’s the purpose of a 2” shotshell in .410? 2.5” data is pretty rare for hunting loads.
I’ve used felt under and over to get a good crimp in 10 bore loads and pressures were same as with only undershot btw. It’s amazing how that little bit of cushioning makes a difference.
do not have the latest manual so I will work off the 2.5 information just start light and I think I seen somewhere the 2'' hulls are for pistols but I will load some when the chance comes .
yep and still I learning about shotguns , rifles were my only fun .
pistol I thank but these are going to be shotgun .
