Then you wind up with a higher pressure round that is still pretty close to the 30-40 Krag. Dies are alot more spendy with a wildcat cartridge w/o much benifit IMO.
I realize that British stuff would be more popular in your neck of the woods but cost VS benifits in the long run I'd stay with something other than the 303.

"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand