Is this cratering?
- Thread starter Iclimb
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Iclimb
Well-Known Member
Unofficial Gun Addict (UGA)
Well-Known Member
^^^^. What he said.
Broz
Well-Known Member
Yes, but in my opinion not from excessive pressure, but from an loose fitting firing pin. The primers are still well rounded on the sides with just a bit of a flattening of the face. Is the load under book max?
Jeff
Jeff
Not due to excess pressure or you would have more flattening and no gap at the edge of the primer.
Also dome primers are much softer and this is not unusual for them.
Pressure cannot be totally assessed by just primers.
Also dome primers are much softer and this is not unusual for them.
Pressure cannot be totally assessed by just primers.
Iclimb
Well-Known Member
I'll check the firing pin. Do you mean "loose" in relation to pin diameter/pin hole dia.? There is no sign of heavy bolt lift.
It is a SPEER reload to spec as far as COAL etc. I got rid of the manual but as I recall it is under max load. I'll post the load maybe someone with a SPEER book can tell me where it lines up.
It is a SPEER reload to spec as far as COAL etc. I got rid of the manual but as I recall it is under max load. I'll post the load maybe someone with a SPEER book can tell me where it lines up.
Iclimb
Well-Known Member
I agree on assessing by primers alone. I'm somewhat of a novice so I wanted to confirm with you guys as to what you're seeing. If I was looking at this in conjunction with a flattened primer I would start to consider too much pressure.
In my mind I could continue to load up, based on what I'm seeing here...???
Thanks guys.
FearNoWind
Well-Known Member
When the firing pin is slightly undersized with respect to the size of the firing pin hole in the bolt face the type of cratering your images display is common. Especially when you have soft alloy primers. So, IMO, based on the images posted, your primers aren't unusual.
FearNoWind
Well-Known Member
When you're at the point of flattening primers you passed extreme pressure a long time ago. Flattened primers are relative to prevailing pressure combined with primer construction material. Some primers are made with some pretty hard metal while others are quite soft. IMO you should never push a load beyond what's needed to do the job in a safe manner. Remember that faster isn't necessarily better and pushing the pressure envelope can make your wife a widow; or the wife of the guy at the next bench.
Iclimb
Well-Known Member
Copy, what pressure signs might I watch for then? Essentially I can't watch for "cratering"...
Broz
Well-Known Member
Watch for the first sign of an ejector pin shadow (circle) on the head over the head stamp. Or any increased bolt lift would be next. I use a magnifying glass to look for pin shadow.
Another would be to knock the primers out and see if they are "muffin topped" or some will call it "top hat" these will roll in an ark on a flat surface when rolled on their side.
But I prefer watching for the pin shadow on a warm or hot day.
Jeff
upacreek
Well-Known Member
I did a lot of searching on this not long ago. Most my rifles do exactly what you see. Doesnt effect performance, near as I can tell. I started going above book max on my .243 and at 3 gr above max I chickened out. Primers were much flatter than yours and no stiff bolt lift, or ejector mark. My 7RM gets loaded above max and the cci primers as well as remington primers show the same cratering and much less flat primers than factory loads.
Iclimb
Well-Known Member
These are CCI'S
Broz, I use a jewelers loop to watch for ejector marks, works great and it's easy to pack. Thanks for the help guys, I appreciate it. I'll run up a few gr. post some more pics.
Broz, I use a jewelers loop to watch for ejector marks, works great and it's easy to pack. Thanks for the help guys, I appreciate it. I'll run up a few gr. post some more pics.
