Welcome to THR. As Bfh_auto mentioned the castboolits site would generally give better responses for this particular question. I cast for pistol and rifle, and while I don't load 8mm I would think a mold dropping a .324 would be more what you're after generally speaking. The Lee 314299 would be better suited for cartridges like 303 British, 7.62x54r, 7.65 Mauser, 7.7 Jap, etc. Considering the variances with 8mm chambers it would help to know in what rifle you intend to shoot cast bullets.