Extruded primer.

[Texrtc]

Went to the range yesterday and was shooting 9mm reloads charged with 5.6gr unique, 115 FMJ and Remington small pistol primers. I have never had any problems with this recipe, however yesterday I noticed that my primers were extruded after firing. It looked like the primer flowed back around the striker. Additionally the spent case rocks back and forth when set on the bench.

Any help on determining the cause is would be appreciated.

 

[JLDickmon]

gun make/model?

 

[Texrtc]

Ruger P95 and Baby Desert Eagle

 

[rcmodel]

That load is well under max, probably by at least .4 - .5 grain or more, and should show no pressure signs at all.

Back when I was young & foolish I ran 6.0+ Unique with 115's in a S&W 39 all the time.
And we won't get into how much +!

I'd suggest you recheck your scale zero, and re-weigh some of those loads to make sure you loaded what you think you loaded.

Probably would be wise to throw some scale check-weights on it too just to be sure it is weighing what you think it is.

rc

 

[gamestalker]

How far are the spent cases being kicked out when discharged?

Do the loads fully and consistently cycle the slide?

Is the brass unusually sooty?

Is there any indication of gas leaking around the sealing edges of the primer cup / pockets?

My first guess, and that is all I can do provide at this point given the above information needed, is that your loads are not operating with enough pressure or peak pressures are occuring late. Often times pressures will behave like this when the case is under charged, as per powder type too. So if it were me, I would pull some and re-weigh them after re-zeroing and checking your scale for accuracy.

GS

 

[ConcernedCitizen]

My guess is an enlarged firing pin channel. I've seen a Ruger P89 show the same symptoms with factory ammo.

 

[Texrtc]

All spent cases are being kicked out at about 4 yards.

With all the loads, the slide has cycled fully and consistently.

The spent brass so no signs of soot nor do the primers show any indication of gas leakage.

That is why I am at a loss of what would be the cause of this.

 

[JLDickmon]

Might just be the hole for the firing pin in the breech face is worn..

would not necessarily mean issues with the ammo..

 

[ArchAngelCD]

According to Alliant the Max charge of Unique under a 115gr Gold dot bullet is 6.3gr. Backing off 10% to the Min gives you a charge weight of 5.67gr so your load using 5.6gr is slightly below the Min according to Alliant. That charge should not show any signs of high pressure so like suggested above, check your scale and be sure it's accurate.

As a side, I'm a little surprised such a light load is throwing the brass 4 yards and you are seeing no soot on the brass, especially with Unique that is usually a little dirty at lower pressures.

 

[Magnum Shooter]

How many times has the brass been loaded? Are the primer pockets tight?

 

[Texrtc]

The brass has been fired 3X. Primer pockets were not loose.

 

[twice barrel]

If its not a headspace problem or nothing mechanically wrong with the gun I would also consider the possibility of a soft primer. Have you loaded for any other guns with the same batch of primers?

 

[ranger335v]

Your loads are so light they aren't pushing the cases back against the breech face so the fired primers are proud of the case head by whatever slack your headspace allows. If they shoot well you have nothing to be concerned about.

 

[bonez]

Your loads are so light they aren't pushing the cases back against the breech face so the fired primers are proud of the case head by whatever slack your headspace allows. If they shoot well you have nothing to be concerned about.

I would second this as a probable cause of the "extruded" primers. Saw it in my .38 when playing around with low power loads for cowboy action matches. Primers started dragging on the recoil shield after firing to the point it became hard to turn the cylinder. Wasn't enough "oomph" for the case to reseat the primer against the recoil shield after firing.