Re: How much to reduce charge when getting ejector marks?
As a Rule of thumb, when I encounter the 1st pressure sign, even slight ones, I reduce that charge by 2%, and call that absolute max, I will also research that load against verified sources. Interestingly that load I declare max often falls within .5gr of a lot of listed max loads (not always but often), some times above sometimes below.
Keep in mind the animals we shoot for food and display are not bullet proof. Contrary to popular belief, they bleed and die just like they did a hundred years ago. Being competent with a given rifle is far more important than impressive ballistics and poor shootability. High velocity misses never put a steak in the freezer.