Sellier & Belliot
They have a loading for them, with IIRC a 196 grain bullet...Inexpensive, and I found them to be quite accuratein my sporterized Mauser...They are Boxer primed, however, my buddy tried reloading some of the cases, and we saw some signs of potential case head seperation after 3-4 loadings...However, I think his reloading skills/setup may be suspect here, as this is the only bottleneck cartridge he's tried to reload.