Thread: Primers, how flat is too flat

Hi all, looking for some advice and sources of information.
how flat is too flat with primers, as an indication of pressure.

I decided to ask more about this after reading another thread on here recently and noticing a couple of flatter than usual primers with what should be a mild load after my last outing.

the 243 is a barnard SM action and i have never had a stiff bolt lift,
load data is
Lapua brass on it's 4th or 5th reload,
CCI 200 large rifle primer.
ELD-M 108gr over 46 gr of RL-26, COL 2.83". Alliant quote a load max for 105gr amax of 46.7gr
75gr HP Hornady /Speer over 44 gr W760, COL 2.64". Hodgdon give a load range of 42-46gr.

The primers used under the W760/H414 were noticeably flatter. See primers 2nd and 3rd from left




Next lot is 358 win shot out of a 1975 Savage 99
Win Brass, CCI 200 primers.
Sierra GK 225gr over 48 gr Varget/2208. Hodgdon give a load range of 45-49gr.
Hdy 158gr XTP over 12 gr Trailboss. Max case volume 14-16 gr based on bullet seating depth

Cases on left had the full power loads, those on the right the trail boss loads.



Thanks all, keen to hear your feed back and comments
Z