Primer Blow Out?

[jbglover]

I have been reloading rounds for my deer rifle for about a year now (model 98 mouser action .264) and have yet to go completely thorugh a box of 1000 count CCI 250 primers.

Problem is about every 20th round or so a hole will be blown completely through the primer and gases will pass by the bolt and hit me in the face. Bullet performance is not affected real bad and velocities stay about the same (crono).

It does sting though! Any thoughts on why this is happening?

[Randy Wakeman]

Excessive firing pin protrusion? Improperly seated primer? Out of tolerance primer pocket? Non-recommended reload recipie?

You are referring to the .264 Winchester Magnum?

[jbglover]

yes .264 win mag. The reloads are conservative, crono at 2950 fps and case mirometer mesurments indicate no excessive pressure.

Primers are not seated flush with the base but are slightly recessed.

It does appear from looking at the primers that don't blow out that the firing pin is hitting pretty hard.

[jbglover]

I have not measured the primer pockets, but this is ocurring with R&P brass that is new or once fired. I forgot to mention the loads are 57.2 grains of H4831

[Randy Wakeman]

jbglover said:

I have not measured the primer pockets, but this is ocurring with R&P brass that is new or once fired. I forgot to mention the loads are 57.2 grains of H4831

With what bullet?

[jbglover]

140 grain nozzler partition

[Randy Wakeman]

Well, I don't know. It seems reasonable to make sure the firing pin protrusion is within spec; same with the primer pockets.

.050 - .060 in. is a common range; I don't know what it is for your specific rifle.

[jbglover]

Soory it took so long to get back, been fishing at Lake Powell. I will have the gun checked by a gun smith. Do you think the primers may be defective?

Thanks alot for your help and input.

[bigdad5]

I know this is a little old but i have heard of two issues with the 264 win mag . one of them was proper primer pocket depth seating and the other was a occasional soft primer. It had to do with a contracted formula about 2-3 years ago . I do not know if the formula problem was fact or fiction and Winchester wasn't talking. But i do think that the long primer pocket was an issue that was fixed. Just wanted to try and help with info i had herd of.

bigdad5

[Randy Wakeman]

The firing pin protrusion is a "likely suspect"-- no more than .055 in. max, .050 in. optimum.

Tight bore, thick brass can add to the situation. A 120 gr. bullet may also make your problem go away.

[jbglover]

This gun does have an extremely tight bore.

Thanks guys

[cburnsid]

I think it would just be to much pressure. When reloading your rounds how often to you check the weight of grains. I know to many ppl that rely on there powder measure to be on after the first right one. I weight every single time for proper grain weight. I would say get a primer pocket cutting tool to uniform the pocket. I would stay away from presses that load your primer for you and get one that is a hand one. It is not that much time and you can feel for yourself that the primer is seated.

[jbglover]

Thanks for the input guys!
cburnsid, I am weighing each load sepreatly, and using a single stage press. Primers are seated using a Lee hand held priming tool. The gun went to the smith yersterday, will let you know what he has to say.