Soft Primers?

[dcali]

About 10:00 am, CDST.

I felt something . . .

Same here. Creepy.

 

[JLT]

Same here. Creepy.

Hmmmm . . .

Hey, Master Yoda! What gives?!?

 

[Webster]

I ran across an issue I've never seen before. (At least I don't think I have - I don't make a habit of examining spent primers). I was decapping some brass, and the pin pushed right through the primer. Inspecting the spent primers showed that most of them came out normally, while others were deformed by the pin, and 2/100 were punctured.

Decapping force was not abnormal. The load, which is not excessively hot shows no pressure signs other than a very slight cratering, which I don't think is real (QuickLOAD puts the pressure at less than SAAMI max). I have successfully used this load with the same lot of brass, powder and primer in the same rifle for several hundred rounds previously, and I don't recall it happening. In fact, I had shot about 600 of the 1000 in the box before this happened.

The primers are CCI 400s.

It's not a problem per se, but it struck me as unusual. Anyone see anything like this before?

Edit: Possibly pertinent - this was in Lapua Palma brass, which has a small flash hole.

View attachment 1048908

When depriming the pin pushes the anvil against the cup (double thickness). The anvil is pointed. Don't know how anything but pressure could explain it? Still have not heard an explanation for the dark color around the edge of the primer. Is it gas leakage?

 

[dcali]

The anvil was wrapped tightly around the pin on the ones that punctured. I wonder if the anvils were softer for some reason and didn’t distribute the load of the pin. I guess the load was too hot for them and made the thin cups wedge a little too tightly. That’s all I can come up with. I can’t explain why this tray was different than the previous 6 in the box. One of life’s mysteries I guess.

 

[Dusty Stevens]

shoot a hotter load to loosen the primer pockets up a bit.

 

[Jdne5b]

I've seen it/had it happen, but only when depriming range 5.56 that's been wet(or wet tumbled without depriming first) and the primers are corroded in the pockets now.

 

[chevytruck_83]

A lot of people bush the firing pin and run the cci 450 primers to eliminate pressure signs on the primer. I’ve personally had great luck switching to the 450.

 

[searcher]

I'd not use the 400 primers in an A/R. Lots of discussion on this recently - there are better choices. To add to what others said about options - while the Russian (Tula and wolf) .223 primers are claimed to be a bit soft (though still tougher than the 400's), the Russian primers with the MAGNUM designation and their .556 primers are well suited to anything you can load safely. I say that as there are still some out there and you don't want to pass them up if your run across them. Seems there are no more coming into our Country at this time (?). If I ever run out of the Russian stock and my favored Federal A/R Match, the Remington 7 1/2 will be my choice. Each are great primers for the A/R.

 

[Rodney]

I had the same problem with the cci400’s. Load shot fine with br4’s, then I used some 400’s because it’s all that I had, and the primers were blowing out. Switched back to br4’s and problem solved. The rifle is a savage which probably played a role due to excessive clearance around the firing pin hole.

 

[L W P]

CCI 400 have a thin cup.

View attachment 1048940

Is there a chart for Seller & Bellot primer dimensions by chance?