The problem is, new brass is 529, it grows to 531-532 first firing. 99% of dies won't size the web area down enough. They'll keep it around 532 with warm loads, 001 clearance isn't enough, hence the reason to take the chamber out to 0.535 in at area. Gives 003 clearance, no more clickers.
I have not loaded 7prc or 300prc, but do have 65prc, 7-300prc and a 7LRM, which all have the same base diameter. All mine are 535 spec reamers at 200 line, I can run them up pretty dang fast for shorter barrels without pressure signs. I also have a roll sizer to size the case web if needed. That'll get rid of clickers pretty quickly as well. I have some 65prc brass that the web will NOT go below 5315 even in the roll sizer, this is the stuff that gives clickers in saami spec chambers. The tightest sizing dies I have found are the rcbs match master, and bullet central micron dies. They size the most aggressively at the base.
