Ranch13;
Thank you for your response. Please tell me, what is the serious fault you find in my reasoning about the pressure test equipment available to the general public?
I simply pointed out the limitations of current strain gauge pressure test equipment, as enumerated by Ken Oehler and others. While strain gauge equipment is much better at estimating chamber pressures than such techniques as judging sticky extraction, miking cartridge base expansion, or eyeballing primers, and we are fortunate to have it available at a price less than a new rifle, it is not as accurate as a calibrated laboratory piezoelectric transducer system.
I read the entire Gunwriters' thread about the strain gauge systems several weeks ago and found nothing there that contradicts either the opinions or facts that I've expressed in these posts. As I said before, I am just looking for accurate pressure data concerning BP cartridges. Pressure measured in a climate controlled laboratory with calibrated equipment is almost certainly more accurate and more reliable than pressure measured with an uncalibrated strain gauge at an outdoor range.
Perhaps you are confusing reliability with accuracy. A measuring system may be reliable and it may give consistently repeatable results, but that does not mean it is accurate. A BPCR strain gauge system, pretty much by definition, cannot be properly calibrated. There is no SAAMI calibration ammunition for black powder cartridges. Without proper calibration, there is no guarantee of accuracy.
If a measuring system is poorly calibrated, and you have no other frame of reference, every measurement it makes could be consistently off by 30% or more, and you would have no way to know it. That's why data from a laboratory calibrated pressure measuring system is preferable to something that you just glued onto your gun. Unfortunately, the laboratory setup costs a heck of a lot more, either to buy or to rent.
If anyone has data obtained with a strain gauge system and would be willing to share it, I would be very happy to receive it. Any data is valuable where none was previously available.
You said you would be quite leery about having to shoot a BPCR match within a couple hundred feet of me and my rifle. You wrote, "Safety is of major importance in the shooting sports, and it looks to me much as tho you have pitched all common sense about reloading with black powder right down the drain."
Seems to me everything I've said thus far is sensible. Safety is always paramount. I thought I'd made it clear that 4Fg loads, safe or not, fall in the area of experimental loads, and in my opinion should not be used at a match or in any venue where other shooters might be placed at risk. What have I said that makes you think I would violate such an obvious concept by taking useless 4Fg loads to a match?
You also referenced the "haphazard approach" I'd taken to loading black powder in cartridges.
In the previous posts, I outlined the graduated procedures that I used in my experimental test series. This was not "haphazard" in any sense of the word that I understand. Given all the cautions and caveats I expressed, given the lack of any overpressure signs with loads using CCI pistol primers that flatten at 35,000 psi, given the strength of the modern bolt action rifles employed, and given the known maximum pressure limit that can be generated with black powder, it seems to me that common sense was well exercised in this test series.
In conclusion, all the objections you've raised were addressed in the thread on the GOEX board and in the posts on this board. Except for one overpressure incident due to an excessively long cartridge case, no overpressure signs were seen with any of the other 4Fg loads discussed. My experimental velocity protocol was concluded safely and without damage or danger to anyone or anything.
Am I bullheaded? Maybe so. My wife would certainly agree with you on that point. But I simply feel that I am stating plain and obvious facts.
There is very little good pressure data for BP cartridges. 4Fg produces enough additional pressure that, in my opinion, it should not be used in BP cartridges. The velocity and fouling gains with 4Fg are negligible.
As you can see, I agree with you on all points of safety and suitability. We just disagree about my common sense in performing this experimental series in the first place.
All the best,
Dick Gunn
a.k.a. Dr. Gunn
