the jeffery cartridges like 450 or the 475 no 2 remind me allways on the famous swedish 40mm bofors AA round and on the other side the 22 hornet case.
this construction is the best when it comes to rimmed cases, build for work under any cirkumstances.the thin rim we have on old BPE based NE cartridges be not the problem today like in the old times.
Originaly it was a iron disc on a coiled case and work with blackpowder. jeffery rework the rim and make it thicker and stronger than before but who has heard from a brocken rim with a sticking case in modern load of 470 , 500NE? I think, this problem is long time gone.
Disadvantage for the jeffery case today is what was very well with cordit powder, the big space inside, impossible to load without filler.
the case is very heavy and more expensive to make than 470 NE or similar.
And last but not least there are two different cartridges with this name, different bullet dia. and different velocity