I posted several new Pressure Trace experiments on my forum, and rather than retype them here, I'll just post a link for anyone who is interested.
Mountain Molds forum

At this point I still have more questions than answers. I've tried to be objective and just stick to the data. So far I still believe that Pressure Trace has good resolution but the accuracy does seem to vary from gage to gage and even from week to week. I still fear that the secondary spikes are real, but not as destructive as primary pressure. As more data piles up we'll have better answers.

At those pressures (~75,000 psi) you should be getting velocities over 2900 fps and approaching ~3000 fps. I don't buy your data.

You can buy or not. I'm not here to sell anything, I'm here to share data and hoping other people will do the same thing, so we can learn from each other. Weren't you the one who told me that primer pockets would start letting go around 80,000 psi? Do you think Bullseye would do 2900 fps at 75,000 psi?


Here's what QL predicts for velocity/pressure with H4895 in my rifle:

2633 fps -- 58 ksi
2705 fps -- 64 ksi
2808 fps -- 73 ksi

The load that blew the primer clocked 2801 fifteen feet from the muzzle. The pressure/velocity relationship that I measured agrees pretty well with QL, even though QL botched the correct charge.

popenmann,
Kind of crazy. I am not impressed with your loads. I wouldn't buy your loaded ammo, though I would believe your data!

Thanks for sharing, while you are still with us.

RIP,
I don't sell ammo. My experimental loads are designed to shed light on the science of cast bullets, not just to make itty bitty groups or slay critters -- those things have already been done. I don't recommend anyone else do stuff like this except as a controlled experiment where the risks are acknowledged and reasonable precautions are taken.

Yes, there are risks, but personally I think there is more risk shooting a break-open single shot with almost any load than shooting a M700 with an overload. If I blow up a barrel, there's a $20 take-off barrel waiting to replace it. Good luck trying to blow up an M700 action.

As for why I do it, this is a small diversion on a very long journey to better understand cast bullets. It would be nice if someone else would do it for me, some well funded, well equipped corporate or government lab, and then I could reap the benefits of the knowledge gained without paying the price. But the reality is that Lyman isn't going to do it and Saeco isn't going to do it and Lee isn't going to do it and the NRA sure isn't going to do it. If a powder company does it (they probably know more than they let on) they aren't going to publish the data because it would open the door to lawsuits. Picture a lawyer telling a jury "those greedy powder companies knew all along that their product could cause secondary spikes yet they continued to sell their dangerous and evil products to unknowing consumers." If the military does it (and they probably know more than they let on, too) they'll wait 100 years to declassify the reports. So if curious experimenters like Denton and I don't do the work, who will?

Read Dr. Mann's "The Flight of the Bullet". He did a lot of wacky experiments, ruined a lot of expensive Pope barrels, and spent a small fortune doing it, but he advanced our knowledge of ballistics. If I can accomplish a fraction of what he did, I'll be satisfied.

We need others to test his bullets in other 3006s, to see if trace is same. And tested in 300 Weatherby, which is long throated.....If
his 06 is long throated and tests in short throated guns show no spikes, then his slippery bullet moves easy at ignition, hesitates because there isn't bigger volumne of powder in 06 like WEA to keep the acceleration constant.The hesitation occurring when charge
is finally getting it on, thus showing a spike.That may be the explanation.May not happen in larger capacity case with long
throat or 06 case with short throat.Ed.

Thank you for the new site, popenmann. I'll keep an eye on it.

popenmann,
Just joking. Glad to see this stuff.
Ed's comments about throats is interesting.
I have not seen any of your comments about the secondary spikes as related to hitting the lands after the bullet is moving. Does long freebore prevent this? Does seating the bullet to touch the lands raise the initial peak pressure and prevent a secondary spike?

[Good luck trying to blow up an M700 action.

"As for why I do it, this is a small diversion on a very long journey to better understand cast bullets. It would be nice if someone else would do it for me,"

Take a look at some of Clark's work. RIP's hair would whiten quickly. His stuff (Clark) is good info and he seems to know what line he should not go over; at least when it comes to fire arms. Politics is another matter. roger