Got a question about flattening primers . This may have been asked before and probably has , however , when working up a load and looking for signs of pressure , i generally begin by looking for flattened primers and "sticky bolt lift" . However question is , when looking at a manual , how far does the book back down after pressure signs ? I have a couple of wildcats and i load for several others , and when comparing to others I'd kinda like a reference point . 1 grain under , 2 grains under ??? Not necessarily looking for the accuracy node just how the book figures max other than a pressure gauge !
Reading pressure signs such as flattened primer is very imprecise. The best way is to chronograph and use the velocity as your guage.
^^^^^THIS
There is great variation in primer flatness at the same pressure, even just using primers from a single lot.
The other pressure signs tend to kick in at around 70 KPSI. In a 308 range case, a grain of powder is very roughly 2500 PSI. So if you're getting those signs, you probably want to back down 3-4 grains.
Also a very approximate statement: In good brass, primers start falling out at around 80 KPSI. If you get that, thank your lucky stars that you still have all your body parts, pull down your loads, sell your firearms, and take up photography.
Im constantly amused by people who think they can second guess a well equipped laboratory by firing a few rounds and looking at the primers or measuring the case head.
