Very nice rifle Mike. I used the Dutch military version of this same rifle for my custom rifle build I documented here on DG a few years back. The cartridge for yours is sure interesting and there is quite a bit of information concerning it here on the web when you google it, as I am sure you know. It had a storied, although a short life span, in both hunting and match rifle shooting. I hope you find some brass or the fixings to make some up. You might want to measure the bore as there seems to be some discussion out there on the bore diameters used.