Primer Punctures! Need help please..

[stanley52]

Ok so I have a 280 AI that I have developed some fantastic loads for, but I continually puncture primers. My original load was 60.1gr H4831sc 168gr bergers, and CCI 200's, and there were no pressure signs except I kept puncturing primers. I sent my bolt in and had it bushed, still getting some punctures, so I dropped the charge to 58.5 which is only .5 above Nosler load data max. Still punctured primers, although the hole is smaller. I say again 0 pressure signs other than punctured primers with either loads. I haven't remeasured the firing pin protrusion but it was bushed by Score High so I'm sure that it is fine. I called CCI and a tech told me to switch to their BR2 primers, he said they had a thicker cup? Everything I have ever read or heard says they have the same cup, and are just held to better quality control. Maybe the material is better? Any thoughts on this? I have also heard magnum primers are tougher. If anyone has some advice please share.. Thanks ahead of time. Can't post pics right now, can on Sunday.

 

[varmintH8R]

My 2C

I would first drop a full 2 grains of powder (56gr) just to see if you are still getting punctures.

I would also work up a max charge test (start low) using a different primer and see if I got the same result.

"Only" 0.5 grains above Nosler Max still makes me nervous, especially as their testing was done on a different bullet. 2 grains over would give me serious heartburn.

What type of velocities are you chasing with your 280AI?

 

[stanley52]

My 2C

I would first drop a full 2 grains of powder (56gr) just to see if you are still getting punctures.

I would also work up a max charge test (start low) using a different primer and see if I got the same result.

"Only" 0.5 grains above Nosler Max still makes me nervous, especially as their testing was done on a different bullet. 2 grains over would give me serious heartburn.

What type of velocities are you chasing with your 280AI?

I worked up carefully with those loads, not pressure signs and I showed a smith the brass and he verified. I was getting 2850fps

 

[varmintH8R]

I worked up carefully with those loads, not pressure signs and I showed a smith the brass and he verified. I was getting 2850fps

Got ya. 2850 is reasonable in my experience - was that with the 60.1 or the reduced load? I actually just started a thread for 280AI velocities as the "2900fps with 180's" claims I see make me shiver. Certainly didn't mean to put you on the defensive, but seeing guys going over book max always gives me pause...

When you worked up, were you getting punctures on starting and mid-range loads? Are all of your punctured primers the same lot form CCI? Something seems weird here, it'd be nice if you could blame it on a bad box of primers and move on.

 

[stanley52]

Got ya. 2850 is reasonable in my experience - was that with the 60.1 or the reduced load? I actually just started a thread for 280AI velocities as the "2900fps with 180's" claims I see make me shiver. Certainly didn't mean to put you on the defensive, but seeing guys going over book max always gives me pause...

When you worked up, were you getting punctures on starting and mid-range loads? Are all of your punctured primers the same lot form CCI? Something seems weird here, it'd be nice if you could blame it on a bad box of primers and move on.

The 60.1 was getting 2850 with a 1:9 26" Bartlein. Yeah I was confused initially because there was no sticky bolt, no web expansion, no excess brass flow, no primer flow, minimal primer flattening, only thing was some decent cratering. When I was working up I didn't get punctured primers till 62.5gr of powder and even with that this was the only pressure signs. The 60.1 did not blow primers at first, then it started blowing them a bunch for some reason, then I had it bushed and turned, and after that it just had a few punctures so I dropped a couple grains of powder and it still punctures them way too often 1/5 maybe, though the hole is very small compared to before. I do wonder if it's a bad lot of primers being that there were 4 misfires in 40. The primer strikes were very deep and the entire primer was crushed in a bit (as expected). There was no reason they shouldn't have discharged. So I called CCI and they said to use their BR2's because they're tougher... First time I had ever heard that and cannot find anything on the Internet to verify that, but CCI said so... So I guess I'll listen and try? Just would like to not spend a ton buying 5 different types of primers.

 

[varmintH8R]

Too bad you are in Kansas, I'd give you a few others to try. Dang haz-mat.

Bet you $1 if you post in the classifieds someone local will give you some trial primers out of the goodness of their heart. I have had several instances of this - LRH members tend to be fantastic that way.

Hopefully it is a bad lot of primers. One other thought- could your primer pockets be shallow? Maybe get a uniformer and see if seating them a little deeper helps. I think this is a loooongshot, but maybe worth at least checking off the list.

 

[stanley52]

Yeah I might have to do that... And yeah I it's possible about the pocket depth I guess..