My first pierced primers?? 6.5x47 and the 136 Scenar

[ttfreestyle]

DJ111, you were spot on with your assessment. Long story short this is a friends gun I helped him put together and we loaded the new brass at my place, all went well. He then did the loading of the fired brass at his place when his dies came in and we met to shoot and that's when the problem showed. I had never ran into this and was totally confused as to what was going on(because the first 100 while new went so well). I measured the resized brass he had left over but hadn't loaded yet and they were 5 thou under new lapua brass measurements. They were 11 thou under the once fired in his chamber brass. If you look at the resized brass you can actually see it in the shoulder/neck area now that I know what to look for. I resized a few that had been once fired in his chamber bumping them 2 to 3 thou and ran a test at 36.0 grains and 37.0 grains and didn't get any flattened primers or anything, then I loaded three that were sized short but had not yet loaded at 36.0 and even at that low charge the cratering wasn't far from piercing it looked to me. I have learned something else from the fine folks on this site, All the replys were greatly appreciated Thanks to all

 

[ttfreestyle]

I do think we will both send out bolts out to gre-tan, I have read a lot of positive feedback on this procedure.

 

[DJ111]

Good to hear! Gre-tan does good work and has a fast turn around.

Dallas

 

[ttfreestyle]

ok for the fifty or so that are undersized, what now? Load at a lower charge and put the bullet in the lands? How can they be blown back out without the issues of pressure ?

 

[DJ111]

Jam the bullets .030 in the lands with a lighter load and shoot them.

Just like fire forming a dasher or brx.

 

[ttfreestyle]

Will do, after he gets the bullets pulled and powder out....ugh! thanks again. Always learning...

 

[lrgoodger]

How were the charges thrown? I've seen some dispensers throw significantly different for one user than another. Fact is, YOU didn't load the second loading, so you don't really KNOW what happened!

 

[DJ111]

Fact is 11 thousandths of headspace and jumped bullets will cause the primers to escape the case head enough to allow primer flow and worse case piercing.

 

[ttfreestyle]

LRGoodger, you are correct I was not there and that is why I am exploring every possibility of what happened as I am the one that headspaced the gun and wanted to be POSITIVE I hadn't messed up. It was not my first build and I am VERY careful but I know I am capable of errors. I do know they weigh each charge on a beam scale as I sold him the scale and we are very good friends and shoot together often. And I hate to say it this way but FACT IS I personally tested DJ111 theory and even went higher on the powder charge with smooth primers as the result. I am very appreciative of all the very knowledgeable and more helpful people on this site than I can ever say. again THANKS to every one that replied.

 

[lrgoodger]

If both loadings were done by weighing the charges, it's not likely that a difference there was responsible for the pressure difference you saw. The first response to your post would be a contributing factor, especially if your original load was right on the cusp of being over pressure. The virgin cases are smaller than the chamber, so a small portion of ignition energy goes to expand the case. The resized case would have not been quite as small as the virgin case, so not as much of the ignition energy would have been absorbed by case expansion. It is doubtful that this small difference alone would have been enough to cause the full pressure differential you experienced. Perhaps it was a number of small things all added together, such as the described case expansion energy combined with a small ambient temperature increase, a small difference in powder scale zero, etc. In the end, if you can pin it down, it will all make logical sense.

 

[Milo 2.0]

I ran into this also, new barrel, new brass, 130 Norma's, and 136gr scenars. Barrel is a Mullerworks 8 twist, 3 groove, Stiller action, over spinning and the 3 groove doesn't seem to be built for speed.
I replaced the firing pin to a larger diameter one, a little machining, and should be cheaper than bushing the thing. No more pierced primers but the pressure is still there. The bad thing with Lapua brass is it wont show pressure signs as easily as other brass. Piercing 450's, you have pressure!