Ladder test, createred and pierced primers.

[Ripdog28]

Not a good day. Did a ladder test on my 6.5 (Impact with small firing pin, Muellerworks 23.5") from 39.8-42g of 4350, 1 round every .2g, CCI400, Hdy 147. Lapua SP case. Full length sized, neck at .291-.292 after loading to 2.83oal. No flattened primers but every one was cratered (Bulged around firing pin impact) with random ones pierced (Low, mid, high charge). The only case that had a swipe and slightly heavy lift was the 42g which was also pierced but no flattening. After firing, neck was only .295 on every case. If it isn't from a crimp, not an over charge, I'm leaning towards the primers being the issue. Going to test a few at 40.4g with some CCI450 primers. Any input is helpful.

I did find an awesome node at 40.2-40.6g which was a whopping 6fps difference per lab radar but fear ill need to redo the whole test.

 

[XLR308]

Switch to the CCI 450 or the bench rest BR4 they have a thicker cup and will handle pressure better. The CCI 41 is another option if you can't find the other two.

 

[XLR308]

Are you sure your headspace dimensions on you brass are also within spec ?

 

[Ripdog28]

Are you sure your headspace dimensions on you brass are also within spec ?

Yes, I pulled up SAAMI specs to double check it wasn't my sizing or chamber. Every piece of brass I measured either after firing or after resizing was within spec. Even pulled out my Mituoyo Micrometer for it as i know calipers can be off.

 

[XLR308]

Yes, I pulled up SAAMI specs to double check it wasn't my sizing or chamber. Every piece of brass I measured either after firing or after resizing was within spec. Even pulled out my Mituoyo Micrometer for it as i know calipers can be off.

I kind of figured you would have checked that but you don't know unless you ask right.
I try and set my FL dies to be in the .001-.002" for set back on fired cases.

 

[wvlapua]

Will a 6.5 Cal bullet drop into a fired case? And was your chamber dry and free of solvents?

 

[Ripdog28]

Problem was primers. Ran the same ladder of 11 rounds with CCI450 and not one issue. All primers were perfect.

 

[wvlapua]

Awesome news and good info. CCI 450 is always a good choice in the high pressure rounds.

 

[Ripdog28]

Awesome news and good info. CCI 450 is always a good choice in the high pressure rounds.

What really surprised me was that 40.4g with both primers went 2719-2724. I’ll stick with that charge for now