I'm just trying to get the throat dimensions with what you call the "plugged case". There is a custom mold for an 8mm round that I am interested in and have been told that the problem is that the meplat is too large to fit the throat of my Yugo M48.
I am going to slug the entire bore as well and there are a lot of lead objects to do that with. Someone mentioned using a .358 diameter slug from my 357 Mag. to slug the bore of the .323 inch bore of the M48 and I think that I am going to do that.