Looks to me that your are shooting 223 ammunition and I am assuming that it is fired in a gas gun.
As Bart has said there are a lot of variables with primers. I have developed loads that gave no indication of high pressures till primers started leaking or were blown. Primers are an unreliable indication of pressure, but they are better than nothing.
If I'm not shooting, I'm reloading.
Last edited by Slamfire; February 4, 2013 at 12:23 PM.