I am shooting a winchester 264 mag with 62gr of H4831sc, 140gr sierra hp and remington 9.5 mag primers. I noticed that after the shot, on the primer where the firing pin has hit, not only is there an indent obviously, but there is a ridge around the hole enough to catch your fingernail on, why is that and is it good or bad???
That can happen with soft primers if the firing pin hole is a bit larger than the pin and doesn't really mean anything as long as the primers aren't flattening, piercing, or showing signs of gas leakage. As long as the primers or cases appear normal, then you're fine. I've seen this happen quite a bit with Fed. and Rem. primers.
I am shooting a winchester 264 mag with 62gr of H4831sc, 140gr sierra hp and remington 9.5 mag primers. I noticed that after the shot, on the primer where the firing pin has hit, not only is there an indent obviously, but there is a ridge around the hole enough to catch your fingernail on, why is that and is it good or bad???
I load my 140's in the 264 at 62 grains as well. The primer noticeably flattens, and I get a crater rim that you really can't see, but you can catch it with your fingernail. This is the same load that I have used for over 40 years, and while I think some are skeptical, I've gotten up to 20 reloads out of one case before I have to throw it out (split neck). That said I'm not sure the 4831 today is the same as what it was 40 years ago, and I see Hodson currently recommends 61 grains as max.
Flattened primers and the crater are signs of pressure, but I've not seen any good guidelines as to how you really tell how much is too much. Another sign is being able to see a round mark from the ejector on the brass where the headstamp is located. I just looked at a few of mine and I see that very slightly on one, but not the others... Probably the one real sign things are not good, is when the case is hard to eject.
My thoughts although I've never tried to load to ultimate max (more than the 62) is that increasing pressure is:
flat primer
flat primer but surface area is larger
flat primer with area larger and with crater rim
same but crater rim larger
case will not remove or hard to remove
I can figure out where the extractor imprint fits in. Seems inconsistent.
I happen to have two of those,one left hand and one right hand and both ambidextrous.I can only get under 1/4" groups by using snapcaps and seating the bullet from the muzzle. sam.
