"Hotcore" said: Well...., let's see here. This seems to "claim" that one of the greatest Reloading Gurus of all time(apparently Mr. Ken Waters) dosen't know what he is talking about. Huuuuummm! Kind of sets the "believability" level for the rest of this post.< !--color-->



EXACTLY!! you'd be surprised how many "facts" people know which just aren't so! The inaccuracy of the "presure ring measurement" method has been scientifically proven by the use of pressure measurement equipment in ballistics laboratories a number of times!! As I said, people as experienced and knowledgeable as Ken Waters, "The great GURU", should know better, and stop repeating old wives' tales. Now, Senor Hot Core, you can believe whatever you want, even if it is wrong. But I would think you'd want to know something for sure, rather than relying on what one person believes, without any scientific background for that belief!



As I said, several ballistics labs (such as H.P. White) have conducted tests in which it was discovered that rounds showing higher pressures with pressure testing equipment produced LESS case expansion than rounds that showed a lot less pressure. This with EVERY VARIABLE being identical. Cases, bullets, powder and primers from the same lot, same powder charge, etc.



This is FACT, NOT OPINION!! I refer you to Lyman Manual No. 46 for more detailed information on this matter. Just because a person is prolific with his typewriter doesn't necessarily mean what he says is correct!!

Deke,

I am impressed too! I don't have a lot of experience with those Barnes bullets and none with the XLC! Anyway, if it were me I think I would stop were you are now.

The problem with the Mauser and the 30-06 case head combination is the the Mauser's barrel shank is soo darned stiff (radially). What this means is that you may well fail the brass before you reach the 0.0015" PRE measurement.

I'll try to explain it without getting too technical, hopefully you can follow:

To expand the Mauser's barrel shank by 0.0015" with the 30-06 case head takes over 80,000 psi of chamber pressure.
The brass of the 30-06 case head will fail somewhere between ~ 74000 and 80000 psi of chamber pressure(blown primer). The brass will begin to flow somewhere around 70,000 psi +/- which will effect the PRE measurement, significantly as you get closer to the actual failure of the case head. The effect has to do with the PRE actually moving rearward into the case head, an area which before did not CHANGE appreciably during firing. In other words, you are no longer measuring the same PRE that you did with lighter loads, you are in fact measuring the PLASTICALLY deformed (and nearing catastrophic failure) case head.

Long story short, PRE isn't accurate enough to predict the threshold of failure of the case head.

So as I stated earlier I think I would stop while I was ahead. Afterall, your ballistics are VERY close to the 300 WSM and 300 Win mag factory loads right now.

Just my thoughts on the subject. I hope they made some sense.

ASS_CLOWN

ASSCLOWN,

Thought more about this after my last post and decided to measure the water in the 280Rem case that has been sufficiently fireformed to my chamber w/many full power loads. It measures approx 72.4gr water to top of case mouth. I don't know if it matters, but my case neck is .050" longer (.300", not .250") than Gibbs specs as pulished in Accu-Load.

Deke.