I had a Lyman 429422, and casting one bullet at a time, re-insert the plug, followed by discarding a number of the bullets due to imperfections, it was a PITA.
They were fine when there were no visible flaws, and weighed to within a + or - 1 grain for consistency, The hollow base seemed to be a good fit for the .44 Mag as it was about 225 grains and velocity was a little higher than the original Keith bullet.
PITA = Pain in the A$$