All reloading manuals suggest starting at the "starting load" and working up gradually from there. No manual ever says take the maximum load you can find anywhere and back off .2 to .5 grains. If you consider how little .5 grains are in a 50 grain load, that's hardly any reduction. Examining primers isn't always an accurate way to determine over pressuring. There are too many variables in reloading for a "one load works for everything load". Barrel inside diameters are not all exactly the same because the machining is not perfect. It is always a good idea to spend some time in the front of the reloading manual learning and relearning the basics. I've been loading for over 50 years and I still reread the basics periodically. Good luck.