uscra112 wrote on Jul 23^rd, 2020 at 7:38pm:


Do you have/is there a link to the lab reproduction ?

waterman wrote on Jul 23^rd, 2020 at 6:17pm:

I read the report and deduced the shooter was reloading with light loads that induced headspace but at the pressure he was getting the brass’s strength was enough to contain the gases. Later the shooter decided to up the pressures using the same brass and when fired the brass failed due to excessive headspace. The shooter knew nothing about how a primer can cause headspace problems on rimless cases loads with low pressure loads. The powder had nothing to do with the rifle’s failure.

Waterman wrote:
A banned shooter shattered one of M Petrov's Low Number 1903 Springfields in .30-06 using a similar but slightly hotter load and cast bullets.  He posted a pic of his face after the shot.  Shooting glasses saved his eyes.  Search on the Single Barrel forum.  

I'd use the stuff, but only in a straight case, and maybe only in a High Wall or a Hepburn.
[/quote]

When you say a "banned shooter", can you be more clear, like banned from reloading? banned from the range he was at? banned from these pages?
I am just trying to get and idea of how this figures in to the overload.
Thank you.

I like the powder but it is position sensitive and that needs to be addressed to get best accuracy. 

Craigd to me it sounds like something caused a detonation to have taken place. The earlier actions made were known to be soft but the explanation of what the rifle looked like after it blew up reminds me of one I have seen and a double charge of unique took it apart. Almost sounds like he mistakingly thought he was using the correct powder and actually picked up the wrong can. I have also heard of this being done and taking a rifle apart. Also a bit hard to believe it had anything to do with excessive headspace the shoulder would have had to been pushed back. Sounds like the owner was very familiar with the proper case sizing process. The die setting I guess could have accidentally been changed if the locking collar was loose when he was screwing it in. But dies also typically touch the shell holder for the correct full length sizing depth and the proper shoulder setback / headspace.

*sigh*   Smokeless powder cannot detonate.  Wrong chemistry.

JLouis wrote on Jul 24^th, 2020 at 2:48pm:

Headspace is in reality the control of brass expansion as the round is fired. A rimmed case has the certainty of the rim to maintain the brass’s integrity during the firing cycle. A rimless case is a balancing act subject to the case shoulder position through the firing of the round. A primer when fired in a rimless case can and will increase the headspace by forcing the shoulder back. The balancing comes when the powder is ignited and the pressures are high enough to force the case to expand out to it’s original safe limits. The rimless case has to have a certain amount of pressure to operate properly, running pressures below that certain amount leaves the case with excessive headspace after a small number of firings. That is why all cast bullets manuals warn of shooting cast bullets loads in high pressure cartridges and not segregating them from one another. 

The guy with the 03 made the big mistake of firing a high pressure reload in a case that had excessive headspace, it’s as simple as that. Lesson learning is never fire high pressure loads in a rimless cartridge that has been subjected to low pressure loads. Most single shot shooters have the advantage of using any and every load due to the rimmed cartridge and it’s ability to maintain headspace no matter the pressure but be warned a rimless case has to have a constant headspace.

Premod70 wrote on Jul 24^th, 2020 at 4:52pm:

Please check the account, the brass was only on the second firing from new. 

Doesn't excessive headspace, usually caused by excessive sizing of the brass, just shorten the brass life? There has been no pressure increase, the fired primers would look normal? If someone misses the signs, doesn't all that happen is the case head is extracted with the remainder of the brass in the chamber?

I would edit to add that modern production probably results in similar rimmed and rimless brass strength, but certainly rimless cartridges are designed for much higher operating pressures.

"  I was under the impression that those low number '03 actions were very hard, not meaning strong, that's why they failed by cracking? I believe signs of brittleness can be seen in some of the blow up pictures, but that's just my opinion. "

The below might help to point out what it was I was trying to say.

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