I recently put together an ar-10 upper in 358 Winchester. It will cycle and run smooth with no issues using 308 brass necked up. My problem is when I try to use Jamison 358 Winchester brass the upper will stick the case in the extractor groove and not eject the case. It will lock the bolt back every time. I'm measured 308 case head and there 0.049 thick the Jamison case head is 0.053 thick. I'm thinking this is my issue but I've never run into this before. Any thoughts. I'd try other 358 brass if I could find it. I also don't mind running 308 case if that's all it will like. Just nice having correct head stamp considering I'm running a 308 upper as well.