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Discussion in 'Reloading' started by FEENIX, May 9, 2014.
Just sharing it!
I don't know where you picked it up(some gun rag), but it represents no truths whatsoever.
Actually, it's completely opposite of EVERY reality!
Sorry, I wish I have more information than that. I was researching a chart and ran into it. I supposed I should have caveat it.
It's not much further off imo than the barrel life app. that's running around... They are all so ballpark that they aren't much better than "your barrel will wear out sometime if you shoot it".
I agree! I've seen them in text form but this is the first on chart form ... at least for me.
Better 'app' for barrel life: http://accurateshooter.net/Blog/barrellife2013oct.xls
The factors to account for in barrel life:
-Your precision with which to detect departure in barrel performance
-Powder heat potential
-Mitigating factors(like melonite treatment)
The linked spreadsheet here has a common and competitive 6PPC load entered.
This is a tiny underbore cartridge using a very cool powder in well cared for barrels, but it's shot quickly in grouping, at extreme pressures, and with precision that lends to immediate detection of issues. So it doesn't see 5-6000 rounds of barrel life like anyone would expect, it sees ~900 before setback or replacement.
If your expectation from a 6PPC was 1/2moa, well then you can't detect accuracy loss -that you never had to begin, and you might think your accurate barrel life is way higher than reality.
So in this aspect it's subjective.
Barrel life is too complicated for a single chart because the causal combinations possible run into many thousands. Just play with QuickLoad a bit to see this.
Thanks for the update ... I had the 2010 version,
The chart is useful as long as you adhere to the caveats in the title
"maximum velocity with middleweight conventional bullets at or about 60,000 PSI with conventional chambering"
"so long as cartridge is loaded to full ballistic potential"
IOW calibers work best with certain burn rate powders loaded to an approx. density
Example - 264 win mags will get "full ballistic potential" with a very slow powder that fills the case like H1000 to H870. If you chose to use a powder in the 4350 group then you would not get full ballistic potential or maximum velocity.
Also, like Mike says, there are other factors which need to be realized as having an influence also, such as heating up the barrel too much, overloading, underloading, cleaning practices etc. etc.
So IMO to use the chart as a guideline you need to assume that normal practices will be used