I just got my 300 RUM Sendero II and have been doing some break in work with it. I measured the new Rem brass at the shoulder with a Hornady LNL gauge with the "E" insert. The shoulders measured 4.466 for the most part with a few coming in at 4.467. Occassionally when chambering a round, I can feel the bolt being a little hard to close, not real bad, just a little resistance and I'm sure this is the 4.467 brass. Once fired brass is measuring 4.464, .002 under. I'm thinking that the chamber is just a min spec and probably in the range of 4.466-4.467 and after firing, the brass is settling down to 4.464. I figure that I will bump the shoulders on the new brass back to 4.464 for a little clearance, but I wanted to see if anyone else has had this issue. Also, this is not a bullet into the lands issure as there is plenty of freebore.