.308 AR - Wrong Primer - Blew Firing Pin Out of Bolt Carrier

[Load Master]

Y'all be nice, the original question is a good one.

The load/pressure issue is a whole nother question that needs a new thread if LM wants to go there.

Yes, I will do a new thread with all the details once I have them all. Might not be to the end of this week.

 

[RugerOldArmy]

Y'all be nice, the original question is a good one.

It IS a good question.

We're kind of an engineering forum here though. Being objective, and expressing opinions on both sides of an issue, leads to a more realistic appraisal of what is happening.

Casting stones at anyone that has an opinion on the other side of an issue, doesn't further the exploration of such an issue.

That said, my apologies, to the OP and the community, if I went too far in making my point.

Occam's Razor applies though...the SE version likely is a primer more resistant to slamfires.

When one of our community experiences and shares a wakeup call they experienced, is our community best served by allowing only those voices that focus on the underlying cause being a component, rather than on the reloading process that if sufficiently conservative, should have protected them from experiencing the issue in the first place? The ejector marks on the case heads (see pic in post No. 7) are already compelling evidence. While waiting for a response from S&B, the case heads could be measured for expansion. Is the goal to find the underlying cause and learn, or something else?

I very much embrace the 'High Road' rules that we all treat each other with respect. Yet there are times in a reloading forum, when people aren't being objective, there is a chance ego is involved. I wonder if being 'PC', and not asking them the hard questions, to allow our members to 'save face', is less of a service to the community than raising pertinent points that may actually help them save their face...eyes...and hands.

 

[hdwhit]

Englishmn wrote:
So we are at 3 different types of primers now, Plain SE and NEROXIN.

Not exactly.

Neroxin is S&B's brand name for their particular formulation of the lead styphnate primer mixture.
See: www.sellierbellot.us/index.php/download_file/view/677/144 The active ingredient in the mixture is still lead styphnate as it is in all non-corrosive primers except for the latest generation of "lead free" primers.

 

[Slamfire]

Read all 4 pages of posts and based on my own experience, you're barking up the wrong tree. If you want to delve into the nomenclature of S&B primers, nothing at all wrong with that. But I think running a 175 gr. Sierra almost 2700 fps out of a 20" AR can only be accomplished by loading to excessive pressures, especially with the powder in question.

I agree, the load is smoking hot! Could use it as a barbecue, two shots and the steak is medium rare, four shots and it is well done!

I should have been using for my given application, and in my last post, it clearly states that the S&B rep, who has all the details stated it was in fact the WRONG primer as shown in their chart here. What I found out for sure, this chart is correct.

I would agree that the representative is correct but his recommendation has nothing to do with pressures caused by primers. Soft, sensitive primers are inappropriate for semi autos, and it has everything to do with slamfires. If you notice, your mechanism does not have a positive firing pin block. I am unaware of any automatic or semi automatic rifle mechanism with a positive firing pin block. Some come close, the roller bolts are very safe in this regard. Your 308 should have a firing pin spring. Take that out, put the safety on, drop a round in the chamber, point the muzzle at the ground and drop the bolt until you get a slamfire. It should not take more than 20 tries. If that does not cause a slamfire, then load a full magazine with those soft, sensitive primers and see if one goes bang all by itself. It is best not to do this with a full bladder as it is very shocking to the nervous system. Slamfires are why soft sensitive primers are inappropriate in semiautos, because more sensitive primers are more likely to ignite by themselves when struck by a free floating firing pin. It has nothing to do with pressures. I would be quite certain that the primer mix is the same between the nice sensitive primers and those nasty, hard, military type primers. The difference is in cup thickness and in anvil shape and height.

If you can't find European military primers, try the CCI #34's. They are advertised as mil spec. Can't find Russian Tula any more, but I bought 10,000 of their mil spec rifle primers, and they are a great primer.

Anyway, be interested when you publish your load information.

 

[HankC]

my primary question was and still is which primer I should have been using for my given application, and in my last post, it clearly states that the S&B rep, who has all the details stated it was in fact the WRONG primer as shown in their chart here. What I found out for sure, this chart is correct.

See my post #45, the S&B US rep says he has never seen the SE while he works there. I have to admit that I did not ask him how long he works there! Allow me to quote his email reply again

"The large rifle primer is the correct primer to use for reloading the 308 Win. As far as the Large Rifle Primer SE. S&B no longer is producing that and I am unsure of what the difference between them was. I have never seen them since I have been working here.

Thanks

Nick Peterson

Magtech Ammunition Company, Inc."

Also see my post #18, S&B does not list the SE at their CZ website anymore.

The rep confirmed from the data and photos I sent that I should in fact be using the heaver cup primers.

I think he just wants to tell you your load is too hot!

The 5,3 LR have a nominal cup thickness of .63mm. The 5,3 LR-SE or 5,3 LRM have a nominal cup thickness of .70mm.

You took measurement yourself in your post #80, do you believe these #s? Awfully thick primers. With your hot load, you may need primer that thick! You are blowing a lot of smoke, need thick cup to cap it.

 

[Reloadron]

bds posted some good material in this thread. Apparently the S&B LR SE primers have a cup thickness of about 0.028" (0.70 mm) and the 5.3 LR have a cup thickness of about 0.025" (0.63mm). Should this be the case the S&B LR SE would be similar to the CCI #34 Military type primers. Beyond cup thickness I am not aware of any additional differences such as angle of anvil. I have used the S&B 5.3 LR primers in .308 Winchester loads for both a few semi auto rifles and a bolt gun and never had a problem. This includes a few loads using AA2495 pushing the Maximum Load.

Beyond this I really have nothing to add.

Ron