Hi Sean,Sean Ambrose wrote:G'day m12vlp,
Out of curiosity what were the conditions under which these loads were fired....and what powder were you using....?
You may find that the load you were using is grand on a nice cool day then on a hot day start to experience some verticle or worse......rupturing cases. I experienced similiar problems with a 338 Winchester Magnum that I had began developing loads for, in particular whilst using Magnum Primers with minimum loads that were taken from the ADI manual. Initially I thought that it was old brass that had corroded overtime and just turned to shit, however, I still had virgin brass from the same batch that was in excess of 10 year old. Having changed the Primer and the propellant this eradicated the problem of rupturing cases.
Another point to note is that Remington Brass is very, very soft. I recently destroyed a few cases whilst attempting to remove 2 thou from the necks.
I am not too familiar with PMC primers, however, I do know that PMC ammunition is loaded relatively hot and would be inclined to think that they may also be a hot primer.
I am not overly familiar with the 303, however, I would be inclined to believe that the load you have developed is certainly up there in terms of pressure.
Regards
Sean
You've asked a lot of the same questions I've asked myself.
The powder was 2209. I originally worked up some loads in the 303-25 and settled on a mid one that was reasonably accurate without being hot so 36.8gr of AR2209. It's an old No1 Mk III action so hot loads are a no no.
Going back through my shooting logs I first used them in early September 2009 so I would have loaded them in August. I then shot them in November 2009 and March 2010. I can remember the march shoot (F-Class at 300m) and that it was pretty warm day. A lot warmer than yesterday. I will say that it's usual accuracy was fading in the march shoot. I just put it down to the thin barrel warming up as I sent down a few quick rounds.
The PMC primers are the old red Russian's. I've probably put through 400+ rounds with this load/primer/pill combination in other brass in all weather. I checked the primers and they were less flattened than the others. I checked them because I was thinking overload and if I recall correctly there was an issue in the past with AR2209.
Primer flattening (yeah i know it's not the only indicator) was the same in yesterdays un-ruptured cases to ones fired earlier.
Maybe I should mic them?
I'm actually kicking myself. I should have held onto a couple and pulled them. At the time I just wanted to get rid of them.