My 400 gr mould was custom, I just stipulated .424 plain base mould that would cast 400gr with Lyman #2. looking at the ID numbers on the mould it was made in April 1984 which would be about the right vintage when I ordered the mould. In hindsight I should have got it made for gas checks (44cal) but I can put a shoulder on the cast bullets for gas checks now using my pullet puller die and collet to hold the bullets in a small lathe.
Photo below of the collet/die setup, where once in the lathe chuck the bullets index the same each time into the collet using a long socket through the lathe centre to open and close the collet for each bullet.
While it is an extra step I can modify quite a few per minute so doesn't take long to get a batch ready for standard 44cal gas checks which size down easily in the Lyman 450 lube/sizer.