In the absence of seating dies a collet type bullet puller is a handy tool to seat bullets. Different collets will cover a range of bullets e.g. a 44 calibre collet will do .423 (404J) bullets etc.

The collet die in the press holds bullets inline which can be seated into cases irrespective of the shape and length of the cases i.e. cases themselves do not enter a bullet puller die.

Just a thought.