MD, I have always enjoyed reading your articles and consider you to be the best common-sense gun writer since JOC.
Your latest article on primers is no exception.
I would like to ask you a few questions. I have been reloading my own ammo for roughly 40 years. I too have found that primers are a very poor method for determining pressure and for all the reasons you stated.
First, I would like to ask you or anyone else here if you have ever seen an example of excessive chamber pressure WITHOUT having a flattened or blown primer? Personally, I have not or at least not ever thought so.
Second, what are the signs that you personally look for to determine if you are at the high or top end of your powder loads?
The reason I am asking this is just this week, I am working up a load for a 270 Win. with a custom barrel. I am using an 8# keg of H-4831SC which I have not used much of. I have worked up to 58 grains of the H-4831SC under 150 grain Nosler partitions with CCI 200 primers along with Lee Collet sized Winchester cases that were fired in the same rifle but with Accurate 4350.
With the H-4831SC, I have already exceeded any book loadings by at least 2 grains and the velocity over my Chrono is still somewhat anemic and far below book velocities.
As of yet, there are no flattened primers. By that I mean the primers are not filling the primer pocket up as is the norm in a high pressure load. There is some primer cup flowing in to the firing pin hole of the bolt face. But there is NO hard bolt lift and the cases extract easily.
For me, bolt lift AND ease of case extraction are the “go-to” indicators for excessive pressure, which is always accompanied by flattened primers at this point.
What are your thoughts on this?


Last edited by SoTexCurdog; 02/11/20. Reason: Forgot some info.