mehavey said:
We've established that:
- The powder charge was pretty much a case filler 97%
- The powder was Same Lot/Same Loading session
- The bullet was right diameter (OP: neck wouldn't chamber otherwise)
- The bullet engaging the lands doesn't raise pressures in extreme
- The primers were the same/in same loading session (and wouldn't raise pressures in extreme)
- Barrel obstruction would have blown the barrel
- Even the next heavier bullet (178gr)/42.5gr IMR4895 is barely 53ksi (in a 62ksi cartridge)
This is the internet. Nothing has been established.
At best, all we can go on are the photos. And those photos indicate an EXTREME over-pressure event.
That rifle saw in excess of 100,000 psi.
Based on the bolt damage and description, I would lean toward even more pressure and a very rapid pressure spike.
The OP can believe and deny what he wants and post what he wants. But the bottom line is that there was something in that cartridge that was just a gnat's behind shy of KABOOM!
That case was
not filled with IMR4895 - not exclusively, at least.**
If you want my honest opinion...
That cartridge was not "#28 in the case of 100."
It was #1.**
I could be wrong. But I don't think so.
The rest of the details were pulled from thin air and reloading manuals, after the fact.
More on my, certainly to be considered, "outlandish and unreasonable," opinion...
Gun powder is gun powder, right?
"Forty one ninety eight" is the same as "forty eight ninety five" ... right?
It wouldn't be the first time I've seen an unhappy ending resulting from such thoughts.
Coincidentally... QuickLoad thinks that 4198 (H or IMR) is right in the pressure window for my estimated chamber pressure with a 178 gr ELD-X.
If it was a lighter bullet, 4227 would do the job (if ignoring other brands and sticking with H/IMR).
**This could be incorrect if everything was loaded on the Dillon seen in the background, with cartridges randomly packaged out of the hopper, and pistol ammunition having been loaded beforehand without a proper cleaning of the powder measure.
Bottom line:
Wrong powder. Contaminated powder. Bad powder.
Case failures are failures. "Pop, hiss, carbon residue."
What those images show are damage to steel, and EXTRUDED brass. Cartridge brass, depending upon composition, generally doesn't extrude even a moderate amount until pressures exceeds
at least 75k-80k psi.
Cartridge brass, as depicted in the provided photo, doesn't do that crap until you see 95,000+ psi for the weak alloys.
You see how the original head stamp is completely erased from that case head? That's because the case head was
extruded. Case failures don't result in extrusion.