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G'day to all you reloaders in the land of the free.Just a quick question from Australia, a friend has a.270WSM which he has only fired about forty rounds in, all factory loads.I just happened to look at the primer on one of the spent cases and noticed that the firing pin indent was very deep and had a distinct crater affect.Is this something any of you have experienced,rifle is a stainless Remington 700.
Cheers from Powelly
That usually indicates a MAX load or it is real close for that rifle. When reloading, and I start getting cratered primers, I will back the charge off.
Collecting once fired brass from the bucket at the range before deer season when everyone is sighting in and checking zeros, I find a lot of factory cases that show what I consider obvious pressure signs, sometimes as many as half the rifle cases. Most shooters of factory loads at our range pay absolutely no attention to their fired brass, many won't even bother to pick it up and put it in the bucket. I see some scary things that I would want to know about my rifles.
I see primers in five distinct stages.
1. Normal - The outer curve of the primer is the same as that in an unfired case.
2. Minor flattening - There is a noticable change in the curve, but it is still present.
3. Major flattening - No curve visable, primer flat and flush with base.
4. Cratering - Completely flat and flush with a raised ring around the primer strike.
5. Pierced - Containment failure with gas leakage.
With the above "guide" in mind, some thoughts....
In handloads, I think Stage #2 is still safe, but will back off if I see Stage #3. Most of my rifles are at their most accurate well below this level though. I think Stage #4 cratering is dangerous and the sign of an overpressure load. I would be micing the case heads carefully to see if they are showing expansion. Not every pierced primer is a sign of overpressure - sometimes there are burrs on the firing pin or it protrudes too far, so it is a mechanical issue with the rifle. But when the piercings are accompanied by cratering and completely flattened primers, pressures are so high that there is usually some difficulty opening the bolt. Any time I see primers that show Stages 3-5 coming out of a rifle I'm shooting, I STOP SHOOTING IMMEDIATELY, pull the bullets, and back off the charge to the most accurate load that does not exceed Stage #2. If I am not seeing acceptable accuracy at the reduced level, I switch powders.
But you asked about Factory Ammo.
Fired cases from many factory rifles show pressure signs at charge levels well below listed MAX loads. Some rifles, otherwise identical to the eye, will begin to show signs at different levels, too. Most factory ammo for the WSM's approaches what a handloader would consider a MAX load, and some rifles will show varying degrees of pressure signs with different brands of ammo.
Bottom Line: In my opinion, those loads are too hot for your friend's rifle. Are they safe? Possibly, possibly not. Would I bet my life (or anyone else's) on that? No Way. If it were me, I would either look for a different kind of factory ammo (I have no idea what kind of selection - if any - you might have available in Oz) that doesn't show primer cratering and excessive flattening, or preferably just shoot handloads that are loaded a bit more conservatively. With pressures that high happening a few inches from my face, I am definitely one to lean towards conservative.
Powelly,
Your not going to find a better answer than Versifier's. Right on the money!
Cheers Smokepole,Versifier andM700P much appreciate your replies.Same friend just picked up 5 boxes factory ammo 120gr ballistic tipped Federals and 140gr failsafe. But he will be reloading now.120GR cost him Aus$82.50 per box and 140gr Aus$90.50 per box how does this compare with US prices? At Christmas time ammo was Aus$37 per box!