Having ordered a Lee custom push-thru die in 0.258, and having opened up its entry-cone to a more gentle one, it occurred to me that this could be a neat size-down diameter for 6.5mm CBoo cores, for patching back (2X notebook paper comes) to 0.268". I had a couple of CBoos in the cold mould, so I tried putting them thru the die, prior to casting up a bunch more. This is the 160 grain NEI pill. Well, there was so much resistance that the CBoo's base obturated out and the whole darn thaaaaang just stopped dead in its tracks. I had to hammer that Boo out from the top with a steel rod and hammer.
Its as-cast band diameter is 0.268", so this was a 10-thou size-down. Have any of the rest of you run into a size-down limit? If so, what was it, in what caliber, and how did you deal with it?
One thing that bothers me about the Lee die sets is that the push-rod's top diameter is ~0.020" under bullet diameter, which causes all sorts of issues that one could avoid with a closer-fit top-of-punch diameter.
Zeek