I have been debating on posting but thought it might help. First, if you ask the primer manufactures where to seat a primer they typically say one or two things. .004 to .005 below the case head or at a .002 crush. Second, think about a garden hose with a twist type nozzle. As you open and close it, it will go from a mist type spray to a high pressure stream. That is similar to how primer seating works and how the flame can be adjusted going through the flash hole. Finding the best place to encourage even ignition. Third, you have to spend a lot of time doing this, both in the shop and on the range. Most people just don't have that kind of time. Finally, my suggestion for folks right now is work on establishing a consistent .002 crush and consistent practices loading. (And quality time on range) I think Orkan will be putting out more soon and he already has some good videos on how to use calipers to do all the measuring for this. Don't get wrapped around the axel with some minor variances like + or - .001. Some brass has variances. Just be consistent. We started playing with this about a year ago. First thing that stood out getting crush with CPS is SD/ES numbers were cut in half. Great discussion and I laughed while listening to Eric and Orkan talk. I knew it would be a shit storm from both sides of the fence. It all matters but you have to test one thing at a time and from a solid base line load. Hope this helps some of you.