.223 pierced primers

[Justin]

Last weekend I was shooting a reduced-course high power match when I started to get pierced primers.

Here's what I was shooting with:

23.7 grains of IMR 4895
Remington #6 1/2 primers
69 grain Sierra matchkings

Has anyone had problems with pierced primers in a setup like this? All the guys I shoot with use #7 1/2 primers, and we think that there might be an issue with the #6 1/2 primers.

Having checked against the book, my ammo is loaded warm, but is certainly within the specs that were laid out.

Also of interest: I've pulled the firing pin out of my AR, and the tip of it now has a little dimple burned into it. Would that dimple have been caused by the pierced primers, or would the dimple be the cause of them?

 

[Clark]

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.

Justin,
Quickload thinks that a 69 gr MK with 23 gr IMR4895 is 41 kpsi.
Quickload thinks that 60 gr SP moly with 27 gr IMR4895 is 52 kpsi.
The latter does not pierce the primer for me with CCI400 small rifle primers.
What quickload fails to account for is that I am jamming into the lands, and the extractor groove is expanding .001", which would indicate at least 62 kpsi, the pressure that CDA 260 hard cartridge brass yeilds at.

 

[Jim Watson]

Remington 6 1/2 is a very mild soft primer, suitable for cartridges like .22 Hornet. The 7 1/2 was introduced for the .222 and its descendant small primer high pressure cartridges. Get some.

The pierced primers probably burned your firing pin tip. A new one is not very expensive.

 

[wanderinwalker]

Agreed with Jim Watson. Get a new firing pin and switch to 7 1/2s. I personally use CCI-400s (and I have tried 450s and BR4s) in my Highpower loads. Not a problem yet with pierced primers, which I cannot say for Winchester Small Rifles (which is a bummer, because I have about 350 rounds still loaded with WSRs). And yes, I have a trashed firing pin lying around and am planning to pick up a few spares to keep with my gear.

FWIW, I am using Varget powder and 77 and 80 grain bullets combined with Lake City or Winchester brass.

 

[Justin]

Ok, so I'll take this for what it is: a fairly inexpensive lesson in the importance of primers.

This, of course, begs the next question:
What do I do with the 100+ rounds I still have loaded like this?

I started pulling the bullets last night, but now I'm not sure what to do with the primed cases. Load and fire them to kill the primer and then start over again using the right kind of primers?

 

[Clark]

1) You could de cap the primers while wearing safety glasses and not accumulating a number of primers close to where you de cap.
Those primers can probably be used again.
2) You could pull the bullets and load a wimpy round with the brass.
Try 12 gr of Blue Dot with a light bullet for a quiet, clean, cool barrel for squirels to 100m.