Casting for the 300 Hamr may be a nogo. the usable boolit lwngth is short and requires deep seating on most boolits. I have set up dummy rounds for the MP 314-410, but it is seated really deep and takes up a lot of powder capacity.
Due to short usable bullet length, there are a bunch of jacketed bullets that cannot be used. The ogive on the long sleek bullets is down in the neck.