text:  Now we're getting into gun geekery. With a 6mm ARC, you have a slightly larger diameter of the rim, a cartridge case rim, which means you have to actually take some metal away from the bolt face. How am I doing so far? That's absolutely correct. So when you take a metal away from the bolt face, which at least in my non-technical mind would say it has to be inherently somewhat weaker or less strong.