You stated that you are not seeing any "real signs of pressure" from this load. Am I correctly assuming that you are solely referring to obvious visual pressure signs from the brass itself or primers?
I'd be willing to bet good money that not only is that load over pressure (SAAMI MAX for .223 Rem = 55K psi), it's WAY over pressure. Try measuring the datum line above the extractor groove before/after firing and see how much case-head expansion you're getting. I'll bet it's greater than zero. It's pretty much the norm for Lapua brass primer pockets to give up the ghost after only 2-4 firings when running .224" "heavies" at such velocities. You may never actually see "obvious" pressure signs on the brass itself or the primers, as such signs are often unreliable indicators and only show up when the pressure is ridiculously high. However, get yourself a Ballistic tools swage gauge (
https://ballistictools.com/store/reloading-products/swage-gage-small-primer-pocket) and check the primer pockets after cleaning the brass. If the load actually is markedly over-pressure, you find out in a firing or two once the primer pockets start to go. If nothing else, it's a very useful tool to have around if you're running relatively high-pressure loads in .223 Rem, because there is no need to continue processing cases when the primer pockets are gone. In the event your primer pockets are NOT opening up within a firing or two, the cost of this tool is minimal and you can still use it to spot check a few cases here and there and maintain your peace of mind about the brass.
