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Primer whats your take
- Thread starter jhedg
- Start date
Primers can be deceiving in terms equating the deformation to pressure issues. It is a purely a qualitative evaluation. If these were from a 30-30 you would probably consider them to be showing signs of pressure but if from a 270 Win then probably not. Same primer but in a 42,000 PSI cartridge versus a 65,000 PSI cartridge. The best way to evaluate them is to watch the amount of deformation as you increase loads and when you begin to see a definite degree of change then you know to be aware you may be approaching the primer's limit.
From my experience, flattened primers aren't always the result of highish pressure. I've a pet 308 load for 110 grn FBHP which uses 36 grns of AR2207 (H4198) which is way down on pressure according to GRT which, is supported by the measured velocities. The primers are always quite flattened in comparison to other loads which are near max & not as flat.
This is the example I've noticed, especially with the 308. I think it has as much to do with the particular load & primer that is used.
In other loads I use AR2219 (also a faster burning powder), AR2208 (Varget) & Benchmark 8208 (IMR8208 XBR). Typically, I notice that the slower burning the powder, the less primer flattening I notice when loaded near max pressure.
I'm not sure if it's the burn rate or the powder weight interacting with the primer blast pressure.
Anyhow, just something I've noticed that has led me to believe that not all primer flattening is due to main charge pressure.
A little too much sizing can cause primers to back out and get "squished", looking like they might be flat, but not.
