High Pressure Signs?
I have been reloading for another of years but usually worked on pistols or a load that worked in a rifle with adequate accuracy and never really refined loads for maximum accuracy.
Lately I have been working on my .220 Swift and have worked up a few nice loads. I am wondering about pressure signs in my loads though and how they present themselves. The primer is what I was always told to look at first but I am coming to the conclusion that it is not a very reliable indicator. In a number of my firearms I have noticed, using factory ammo, signs that I would consider high pressure by looking at the primers. Flattening seems to be the most common, there have been some factory loads I shot that really flattened the primer.
Recently, I have been using various powders and and bullets with the same brass and primers. On my most recent loads the pressure signs were completely different from past loads though; as I approached maximum published loads with H380 the primers began flattening with no firing pin cratering. The other load I had been working with was IMR4831 and as I approached max the primers only slightly flattened but cratering became much more pronounced.
These two powders are of similar burn rate, the 4831 being a bit slower. Does this explain the difference in pressure signs?
I have heard of other methods of looking at pressure signs, what are others doing with good results?