Any of you guys ever try them? Years back after reading about the idea in Col. Harrison's notes I made some for some single cavity Lyman rifle moulds that I had at the time. Must have been prior to owning a computer as apparently I made no notes about it. All I have are favorable DIM memories.
So today I made one for my DC Lyman 9mm mould and tried a few. Immediate thought was it seems to cool faster and "feels" smoother. Have one sprue hole in it that evidently needs a little polishing as it likes to hang onto the cut sprue but that shouldn't take long to do.
After I spent a couple more sessions with it I may just make a couple more. Seems like it might be time well spent.