JohnSKa,
I'm not advocating for a mismatch. Lets just lay that strawman aside ok? I want to know why this issue doesn't show up with every pull of the trigger when there is a mismatch, and sometimes when there isn't a mismatch. If if was the chamber, it should show up every time you pull the trigger. If it doesn't show up every time you pull the trigger, then odds are it is something with the ammo. Can you fault that line of logic?
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Again, I come back to the observation that you seem to be working hard to come up with any possible way to explain the problem short of accepting the one that is most obvious, and the one that the experts, standards organizations and ammunition companies give us.
Ok, so you don't like the data from those folks. Luckygunner's pressure data shows that shooting 5.56 ammo in a .223 chamber results in pressures over SAAMI max when shooting .223 in the same chamber does not--look at the pressure data curves provided in his article. Look at his wrapup--he advises against the mismatch.
Basically, everyone who has any access to pressure data agrees that the mismatch should be avoided and provides a similar explanation of why that is true.
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Ok, so explain to me why the mismatch doesn't cause a popped primer EVERY time if it is really a chamber issue.
The chamber pressure data shown was higher than SAAMI spec, not disagreeing with that at all, simply pointing out that it takes something different than the measured pressures we've seen to pop a primer back out of a pocket.
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Basically, everyone who has any access to pressure data agrees that the mismatch should be avoided and provides a similar explanation of why that is true.
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Except that similar explanation doesn't explain why Radway Green has been known to pop primers even in 5.56 chambers. The exception proofs the rule, meaning that the "similar explanation" is insufficient to explain all occurences of popped primers in ARs.
And the ones that show the pressure trace data, luckygunner and shootingsoftware.com, show some very interesting results, even using 5.56 data in 5.56 chambers, which would explain why we occaisionally see popped primers even when there is no mismatch between ammo and chamber.
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You're seem to be concerned with their credibility, but there doesn't seem to be any real evidence calling that credibility into question. I think that most would agree it's a bit backward to start off the assumption that Winchester, Hornady and SAAMI need to prove their credibility when it comes to ammunition and pressure and that until they do we must accept anyone's proposed theory as having the same weight (or more weight) than the explanations these organizations provide.
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I don't know if you read research journals, but having access to research data is important into weighting the relevance of conclusions drawn. I'm not saying that there is a grand conspiracy to sell more 223 ammunition, so let that strawman drop too. When you don't have access to data and methodology, you can't really evaluate what is going on. For example look up the ALLHAT trial and understand that all the drugs in the trial were shown to be better than placebo, but until ALLHAT those drugs had never been evaluated against each other to determine the most effective course of treatment for hyptertension. Every drug going into that trial had FDA approval and had good data showing that the drug was effective, but until the data was directly compared across drug classes physicians had no idea what would be an optimal treatment regiment.
Or take a look at Michael Mann, still refusing to share his temperature proxy data and methodology so that others can see if they draw the same conclusion. Or the infamous "tin can" ammo that had cold weld issues leading to unsafe pressures, that the Army blamed on competitors greasing their bullets. Was it the ammo or was it the grease?
So I'm not saying that SAAMI, Hornady, Winchester, et all are not credible, I'm saying that we can't prove it for the purposes of this discussion since we don't have access to their data. You can say that they deserve your trust all you want, that is simply not good scientific practice.
Heck, even the scientific debates on whether DNA was conservative, semi-conservative, or non-conservative were all over the board until some researchers got smart and used nitrogen isotopes, e-coli, and a centrifuge to show that DNA is conservative.
Jimro