Factory Berger Ammunition and two pierced primers

[LGKLAS]

Hello Everyone,

Could not find an on point forum so am asking here. I have been using and liking Berger's factory 6.5 CM 140 gn Hybrid Target ammunition. Box MV is 2850 and thru my RPR 24" bbl am getting 2820. I've just under 1000 rds fired thru this barrel and all but 80 have been Hornady ammo and reloads. I am wanting to mirror this round, reloading.

Yesterday I was at the range and fired about a dozen of my own reloads without a glitch. And brought a box of the Bergers along. I fired 18 of of these. After firing three, the fourth primer was pierced. I checked things out and did not see any harm done to rifle or bolt face. I waited a bit and began firing again. And after firing half dozen or so more, another primer was pierced. My range session was two hours. Slow firing. 60 degrees.

My thinking is two of these primers were 'thin skinned' or Berger, during its loading process over-charged a couple cases. I have not had any pierced primers shooting any other ammunition with this rifle. Winchester, Federal, Hornaday and my hand loads, CCI and Federal primers. And, until yesterday, the rifle has fired the Bergers glitch free for nearly 80 rounds.

So, what do you all think? A couple of flawed primers? Over charge? Other? Thanks in advance for your thoughts. lg

 

[PatMiles]

Pics of pierced primers?
I would dial up the folks at Berger and run this past them, see what they say.

 

[Ned Ludd]

I would also ask the folks at Berger what kind of primers they were using in that load. Some cups are more prone to piercing than others.

 

[PWPUU]

6.5 CM can come in large or small rifle primers. Any chance there was a difference between primer size in the pierced vs non-pierced ammo?

 

[Evan]

RPR also has a large and sloppy firing pin. Mine craters even moderate loads.

 

[LGKLAS]

RPR also has a large and sloppy firing pin. Mine craters even moderate loads.

Thanx for reply. Never had any cratering happen. Loading under max charge weights. Using Fed LRPs and CCI SRPs.

 

[LGKLAS]

6.5 CM can come in large or small rifle primers. Any chance there was a difference between primer size in the pierced vs non-pierced ammo?

This happened with the SRPs Berger was using in the manufacture.

 

[LGKLAS]

I would also ask the folks at Berger what kind of primers they were using in that load. Some cups are more prone to piercing than others.

Thanx Ned, I will call Berger. I spoke to a Corey there one time about load info for their 144s. Got his number somewhere.

 

[LGKLAS]

Pics of pierced primers?
I would dial up the folks at Berger and run this past them, see what they say.

Ned also suggested calling Berger. Will do. Part of reason for asking was to see whether anyone else had the issue with this box ammo. Thanx for reply.

 

[Ned Ludd]

Ned also suggested calling Berger. Will do. Part of reason for asking was to see whether anyone else had the issue with this box ammo. Thanx for reply.

Another consideration might be the firing pin hole. Too much clearance has also been associated with that type of issue, and the remedy for that can either be as simple using a different primer with a harder/thicker cup, or having the firing pin hole bushed. I think you're starting at a good place by trying to find out of anyone else has observed this issue with the same ammo. Good luck with it.

 

[Carolina Hillbilly]

I had it happen last week with the Berger 140 SRP in a Terminus Zeus. Primers looked fine until one popped. No ejector swipe, even on the one that pierced. Lot#P001726

 

[Laurie]

This happened with the SRPs Berger was using in the manufacture.

Definitely a bolt / firing pin issue then. This is a very common issue with factory rifles and high-performance / pressure cartridges with small primers. If you do a search on the forum / AS site about bolt-bushing work, there is a good size industry in the US gunsmithing trade doing remedial work - turning down the factory pin tip diameter and boring out the bolt face before fitting a bushing with a smaller dia. hole and set up for much closer tolerances. Greg Tannel was an early expert in this field, but there are now many others.

https://www.gretanrifles.com/product-page/bush-firing-pin-hole-turn-pin

Ben Chappell (@Grimstod on the AS Forum) is another who npow does this work and has had excellent reviews from other forum members. Do a search as follows:

https://forum.accurateshooter.com/search/21878/?q=grimstod+bolt+bushing&t=post&o=relevance

Bearing in mind this site was originally 6mmBR.com specialising in this cartridge and its derivatives, literally thousands of words have been written on this issue and rectifying it. In an era when Remington 700 actions and similar were far more commonly used in custom builds for the BRs, bolt-bushing was a near standard step in the build otherwise loads, pressures and MVs often had to be significantly reduced. Whilst the BR and its derivatives was the first modern SRP precision cartridge to go near mainstream, the last 15 years has seen a huge increase here with 6.5X47mm Lapua and now SP brass options on many other traditional LRP numbers such as 308 Win, 243 Win, 260 Rem etc from ADG, Peterson and with the Creedmoors and 308 Win, Lapua offering both types.

I learned the hard way about this when I had a 308 FN Special Police Rifle rebarrelled in the then near new 6.5X47L some 10 or 12 years ago. Primers cratered at every loading level / pressure including Vihtavuori's mild starting loads. Blanking (the correct name for the primer cup failing and blowing a disk out into the bolt) began at starting plus 1gn. Nobody did bolt jobs in the UK at that time (and whilst on offer now are expensive at c. £300 / $400 US) so it was a case of forced rechambering to 260 Rem to return to LRP brass use. Cratering / blanking is FAR less of a problem with LRP cartridges than with their SRP equivalents even at equal pressures.

So the answer in your case is to either have a bushing job done and / or to only buy or load ammunition in LRP brass. That's no great loss in your case as the LRP Creedmoor variant is more widespread and there are some excellent makes in this form including the Lapua LRP version.

 

[Carolina Hillbilly]

Definitely a bolt / firing pin issue then. This is a very common issue with factory rifles and high-performance / pressure cartridges with small primers. If you do a search on the forum / AS site about bolt-bushing work, there is a good size industry in the US gunsmithing trade doing remedial work - turning down the factory pin tip diameter and boring out the bolt face before fitting a bushing with a smaller dia. hole and set up for much closer tolerances. Greg Tannel was an early expert in this field, but there are now many others.

https://www.gretanrifles.com/product-page/bush-firing-pin-hole-turn-pin

Bearing in mind this site was originally 6mmBR.com specialising in this cartridge and its derivatives, literally thousands of words have been written on this issue and rectifying it. In an era when Remington 700 actions and similar were far more commonly used in custom builds for the BRs, bolt-bushing was a near standard step in the build otherwise loads, pressures and MVs often had to be significantly reduced. Whilst the BR and its derivatives was the first modern SRP precision cartridge to go near mainstream, the last 15 years has seen a huge increase here with 6.5X47mm Lapua and now SP brass options on many other traditional LRP numbers such as 308 Win, 243 Win, 260 Rem etc from ADG, Peterson and with the Creedmoors and 308 Win, Lapua offering both types.

I learned the hard way about this when I had a 308 FN Special Police Rifle rebarrelled in the then near new 6.5X47L some 10 or 12 years ago. Primers cratered at every loading level / pressure including Vihtavuori's mild starting loads. Blanking (the correct name for the primer cup failing and blowing a disk out into the bolt) began at starting plus 1gn. Nobody did bolt jobs in the UK at that time (and whilst on offer now are expensive at c. £300 / $400 US) so it was a case of forced rechambering to 260 Rem to return to LRP brass use. Cratering / blanking is FAR less of a problem with LRP cartridges than with their SRP equivalents even at equal pressures.

So the answer in your case is to either have a bushing job done and / or to only buy or load ammunition in LRP brass. That's no great loss in your case as the LRP Creedmoor variant is more widespread and there are some excellent makes in this form including the Lapua LRP version.

Have you seen the firing pin in a Terminus Zeus? It’s about as tight as any other benchrest style action.

 

[Laurie]

The proof of the pudding is in the eating as they say. There are other factors involved such as firing pin weight and mainspring strength / pressure. There was an in-depth two or three-part technical feature in the old Precision Shooting magazine many years ago explaining what happens in SRP blanking in the PPCs mainly. Half of it was above my head, but I took enough in to understand a very complex series of action indeed is involved with many factors. The fact too that PS editor Dave Brennan gave it so much space shows too how big an issue it was in the benchrest aficionado's in-house publication despite the widespread use of very expensive and finely built custom actions.

Anyway, the OP asks about his experiences with the RPR, which is well known for this (cratering / blanking) issue.

 

[shoot4fun]

I had it happen last week with the Berger 140 SRP in a Terminus Zeus. Primers looked fine until one popped. No ejector swipe, even on the one that pierced. Lot#P001726

You have pressure signs showing with the two on the left and a sure sign on the one that pierced.
Check the throat for carbon ring because (even sporadically) that can cause the sudden pressure signs you are getting. Also, it wouldn't hurt to give a call to Berger and see what they can add.

 

[Carolina Hillbilly]

You have pressure signs showing with the two on the left and a sure sign on the one that pierced.
Check the throat for carbon ring because (even sporadically) that can cause the sudden pressure signs you are getting. Also, it wouldn't hurt to give a call to Berger and see what they can add.

It was shot number 39 on that new barrel. I shot a box of Prime 130’s and 19 of those before the primer pierced. I’m not too worried about my setup, I only posted for the OP as to support someone else was having an issue with these factory loads. I normally don’t use factory ammo anyway, was just zeroing the scope and getting the bore shot in before load development.

 

[shoot4fun]

It was shot number 39 on that new barrel. I shot a box of Prime 130’s and 19 of those before the primer pierced. I’m not too worried about my setup, I only posted for the OP as to support someone else was having an issue with these factory loads. I normally don’t use factory ammo anyway, was just zeroing the scope and getting the bore shot in before load development.

Wouldn't be either, especially the Terminus Zeus. I have one in the works that will be replacing a Curtis Vector.
Also, my response was based on not realizing those were not the Op's fired brass.
It is my feeling about what the OP's issue may be. I apologize for any confusion.

 

[gunsandgunsmithing]

Three main factors that typically cause or contribute to pierced primers, in no particular order..
Sloppy pin fit
Weak fp spring and
Excessive headspace, not uncommon on new brass.
Pressure would be far down the list.

 

[Evan]

I had it happen last week with the Berger 140 SRP in a Terminus Zeus. Primers looked fine until one popped. No ejector swipe, even on the one that pierced. Lot#P001726

I've had this happen too with some old Fed210 LRP. Had 2 out of 1000 that pierced with no other signs of pressure or other problems. Used the same load - 41.7gn RL17 in a 6.5 Creedmoor shooting 147ELD, with all the primers. I concluded that those 2 most have just been faulty.

 

[qwk]

This is common problem with the later lots of that ammo. The early lots had a much milder load, and much lower velocities. As a result,
Berger no longer makes SRP 6.5 creed ammo.