Hello from a fellow uk rifleman,
I have recently been down this route with my 8mm Steyr Kropatschek and after doing various slugs (mine slugged out at 0.332" on the grooves) and a pound cast I brought a NOE 340220 mould from the recent group buy. It is a fantastic mould and Swede was a pleasure to deal with so I have no hesitation in recommending them to anyone. Only cast with it a couple of times now and am still learning but it is turning out some great bullets. I modified a Lee 0.329" lube/sizer die to 0.334" and made a new push through ram which, after rolling in Alox, sizes the bullets a treat. Heres my first attempt.
I couldnt find a M die that was of the right size so I made a spud to fit into a Lee 8mm Lebel neck sizing die and after a fair bit of fiddling and polishing it seems to do the trick as well.
Like you I am waiting for my variation to come through so I can bring it all together and get the old girl down the range for a bit of recoil therapy!
I you want a few of the boolits you are more than welcome-just pm me a delivery address and I will stick some in the post.
Good luck.