I am a Norwegian BPCR shooter .
This cartridge has its origin in Sweden as well as in Norway .
Her is what we use to do when loading for this old rifles,
which we do a lot .
There are several bulletmoulds to choose from .
I use both Lyman plains 395 gn, Lee 450 gn
and Lee 500 gn .
The latter two of those are too big out of the mould to chamber
and i therefore use to size them down in two steps
to get a dm of .501" .
The first step is through a .509" lubesizer and i finish
by pushing them through a .501 Lee sizer wich mounts in to
a regular reloadingpress .
Cast in pure lead they bump up just fine and shoot very tight
groups at 100 meters and at even longer ranges .
The Lyman plains are .503" out of the mould, and does'nt
need any further treatment other than lubing .
I use to charge this cartridge with 65 gns of Swiss#4 .
Good luck !