Thanks for the reply, xausa. I just checked the neck wall thickness with my digital caliper and both cases are 0.0085". I'm not sure of the vintage of the factory Kynochs. Over the last couple of years I've come across and bought 4 boxes of the 245 grain Kynochs and one of RWS 281 grain in 9x57. The type C also came with 8 factory rounds that have a different headstamp than the others. Not sure who made those. The bullets are silver like the RWS, but much shorter in a lighter bullet. I wonder if the neck thickness would be less if I sized up a 7x57 case instead of a 8x57? I have rifles and brass in both those calibers. I've got 9x57 dies and I'll give it a try later.