Pierced primers

[Longwalker]

I was shooting my Beretta Silver Sable 9.3x74R O/U double rifle today and noticed that two out of five cartridge cases fired in the bottom barrel had pierced primers. A little soot on the outside surface and a tiny little hole right through. I have not had that problem with this rifle ( or any other rifle ) before. I have usually used Norma factory ammunition, or RWS, or handloads with Federal 215 or Remington 9-1/2M primers in this rifle. During todays shooting session I used Norma factory loads and handloads with Remington primers with no problems. The ammunition with pierced primers was factory loaded PPU. It was the first time I've shot that brand of ammunition in this rifle. The PPU ammunition shot accurately, seems to show normal case expansion, and regulates well in my double.
I have two questions:
In your experience, does PPU ammunition commonly show this defect ?
If I continue to shoot the ammunition, am I likely to damage my rifle or injure myself ?

 

[Wyatt Smith]

When I had pierced primers, it was due to excessive head space. I would have the headspace measured. Maybe the PPU brass has a thinner rim.

 

[browningbbr]

I've had pierced primers on a Mauser 98 in 6mm Rem. The fault was mine: When I installed the Speedlock firing pin, I cut it to 0.060" protrusion, but failed to round it enough. It acted like a punch when fired. A little rounding with a micro file solved the problem.

I recommend looking at your firing pin with a good magnifier. It costs nothing and would at least let you rule out that as a problem.

Either way, good luck with solving this.

PS: Headspace on this rifle is at the low end of SAAMI specs, so in this case, headspacing was not a factor.

 

[fourfive8]

Sure sounds like extra headspace- caused by either the gun or the ammo. Without disabling or removing the extractors and checking directly you might be able to narrow the likely cause a bit. Simply size a fired, offending PPU case as per normal, seat a primer and fire it. If it is caused by excessive pin protrusion or too sharp a pin nose that should cause a piercing. If it doesn’t, almost certainly excessive headspace caused by case itself- rim too thin.

 

[Bob Nelson 35Whelen]

I was shooting my Beretta Silver Sable 9.3x74R O/U double rifle today and noticed that two out of five cartridge cases fired in the bottom barrel had pierced primers. A little soot on the outside surface and a tiny little hole right through. I have not had that problem with this rifle ( or any other rifle ) before. I have usually used Norma factory ammunition, or RWS, or handloads with Federal 215 or Remington 9-1/2M primers in this rifle. During todays shooting session I used Norma factory loads and handloads with Remington primers with no problems. The ammunition with pierced primers was factory loaded PPU. It was the first time I've shot that brand of ammunition in this rifle. The PPU ammunition shot accurately, seems to show normal case expansion, and regulates well in my double.
I have two questions:
In your experience, does PPU ammunition commonly show this defect ?
If I continue to shoot the ammunition, am I likely to damage my rifle or injure myself ?

@Longwalker
If it was only 2 out of 5 I wouldn't be to concerned. More than likely an ammo fault because as you said it has never happened before.
If it was me I would shoot the rest of the PPUs off and reload with your usual primers. I doubt the occasional piece will do any damage. If it was happening with your other rounds I would get the rifle checked.
PPU have been known to load some rounds a bit hotter than normal. I have seen a brand new Sako 6.5x55 lock up and needed to have the bolt tapped open wit a lump of wood. This was the second shot with the rifle and a brand new box of PPU ammo.
Bob

 

[sestoppelman]

Just use different primers or ammo. Likely soft primers, perhaps a slightly long firing pin. HS is the last thing I would suspect. Long HS would allow the round to be move forward upon the strike and cause a light strike rather than a pierce.
You cant prove anything by firing a primed case in the gun, no pressure, no expansion of the case, doesnt prove a thing.

 

[crs]

Never heard of PPU and I will surely try to avoid that brand.

 

[sestoppelman]

Its PRVI, same thing. Yugo ammo, usually quite good and inexpensive. I have shot lots of it and used their brass, nary a problem.

 

[Inline6]

It is more than likely soft primers. I personally would not continue to use that ammo. Torching the firing pin or damaging something internal is not worth a box of ammo IMHO.

 

[fourfive8]

It certainly can be soft primers, but isn’t the idea here to pin down the real culprit?

With excess headspace the same process that causes flattened primers can also cause pierced primers. During a complete firing cycle, the firing pin does not push the case forward. The primer detonation pushes the case forward while pushing the primer rearward. After primer detonation and the main charge fires, max internal pressure is reached pushing the case head section rearward until the case head is stopped by the breech block or bolt face, re-seating the primer and many times flattening it in the process. If the firing pin is still protruding, it can pierce the primer. Extra headspace can also account for false excessive pressure signs because of the primer flattening.

 

[sestoppelman]

That this is the only ammo or primer that has caused this issue with this rifle is pretty indicative that the primers themselves are the problem, not the rifle.
On the few occasions that I have had a pierced primer it was always the primer that was the problem. Years ago however my dad had a rifle built that would pierce Winchester primers. He switched to CCI, a usually harder primer and had no further trouble. We continue to shoot that rifle today with CCI 200 with no problems. HS is fine.
If the rifle had done this with other primers, then yeah look at all possibilities..
Its almost certainly the primers here and not the HS that is the culprit.

 

[Inline6]

It certainly can be soft primers, but isn’t the idea here to pin down the real culprit?

With excess headspace the same process that causes flattened primers can also cause pierced primers. During a complete firing cycle, the firing pin does not push the case forward. The primer detonation pushes the case forward while pushing the primer rearward. After primer detonation and the main charge fires, max internal pressure is reached pushing the case head section rearward until the case head is stopped by the breech block or bolt face, re-seating the primer and many times flattening it in the process. If the firing pin is still protruding, it can pierce the primer. Extra headspace can also account for false excessive pressure signs because of the primer flattening.

Agreed. This was the first time he has seen this. Also only with this ammo. He is certainly able to run down everyone's theories.

Facts are:

He hand loads and shoots factory and never had this problem.

Tried these for the first time and had issues.

Continue to use this ammo can cause major damage to the rifle.

KISS

Stop using ammo, if problem arises again will have to start looking at things list.

How many rounds down the rifle? 10 or 1000. If it is over a couple hundred or close to that, I will say again ammo, could be a hot load, soft primers, or who knows. Common denominator is the ammo. I personally would start there. My.02 which is worth less than that.

 

[Longwalker]

Thanks for all the suggestions!
To investigate further, I used a digital caliber to measure the rim thickness of Norma, RWS, and Hornady ammunition compared to the PPU ( Prvi Partizan) and all seemed the same within very small variations.
I then placed a couple of fired primers in new unfired / unprimed brass. Only pressed them in part way, then I closed the rifle, first on the top barrel, removed the case, then repeated on the bottom barrel. The primer protrusion should = the headspace. Measured this way, the protrusion of the primer was 0.008" or 0,23mm for both cases/chambers. That's a crude way to measure, but it seems to me that headspace is slightly more loose than I'd like but is probably OK.
I checked the surface of the firing pin. The lower pin seems not quite as nicely rounded like the top one and is at an angle compared to the top one, which may contribute to pierced primers, I don't know for sure about the roundness ( difficult to see) but the impact is not in a straight line. Just the way the rifle was designed.
I am left with the impression that the primers cups of the PPU ammunition are too soft to use in this rifle in the bottom barrel.
I'll shoot the rest of that one box ammunition off in the top barrel only. And will avoid PPU ammo for this rifle in the future. I like PPU generally, ( good value practise / smaller game ammo) and don't think it's bad ammunition, but it doesn't seem to match my rifle's needs.

 

[Longwalker]

An update of this old post. I wasn't satisfied with my investigations so I removed the stock, removed and inspected the firing pins. It looks like the lower firing pin is actually a bit too sharp. It does not have a nice rounded profile like the top one. So I contacted Stoeger Canada and they are ordering a replacement from the Beretta factory for me. After I install it, I'd gladly go back to shooting the PPU ( Prvi Partizan) ammunition, it shot accurately and is readily available and quite cheap. I'm confident that the plain cup and core bullets will be effective for hunting the smaller species of game appropriate for this cartridge.

 

[Shootist43]

Longwalker, thanks for "closing" the loop. Hopefully this minor fix will get you up and running.