08-30-2013, 05:13 PM
mseric Wrote:The Grendel has a MAP of 52K psi. At what psi would you expect to see "pressure signs" in the Grendel Primers?58-60k just like the rest...CCI 450s and 41s a little more. It will start with light cratering then grow to where you can catch a fingernail on the edge of the crater... time to back off 1/2gr and work down looking for accuracy. The G has a 52k psi MAP to protect the bolt. The case will handle 60 but not much more if you expect any life from them. If you have a bolt that can handle the higher pressure shown by the primers the case will. I've been running the 6.5 loads high around that 58-60k since 05. I broke 1 cheap 8620 7.62x39 bolt along time ago.
If you are new to reloading it probably isn't a good idea to push things much until you KNOW you know how to read signs of pressure. Setting up the resizing dies wrong can give false signs. Some match chambers are cut so close to the size of the brass to allow pushing the pressure the brass itself will not show many signs until it's too late. Sloppy chambers will show signs early. Pushing the shoulder back too far when resizing creating to much headspace will produce flat or blown primers, not from excess pressure but it allows the primers to back out and then get slammed into the bolt face when pressure builds high enough in the chamber.
I've been reloading since the late 70s and developing wildcats since 82. I still make mistakes, the last one sent pieces of brass through my lip and into my face. That turned out to be a 1gr overcharge due to a sticking powder measure. When you're running on the edge it doesn't take much to cross the line.
XC, increase in small steps and watch what others have done on this site. Don't stray to far from the masses...yet.