Factory ammo primer cratering problem

[Cadeuses]

Ok, I need some of the experts out there to look at the following pictures and let me know what they feel is the problem here. What I am seeing I believe is a cratering or bulging of the primers against the firing pin.

Here is the Factory ammo I have put through my new Remington Model Seven Predator I bought on May 12:



This next pic is a closeup of one case. Note the primer.



This is a pic showing all three cases with the same primer problem. As I mentioned, all are factory ammo fired through a new Remington Model Seven Predator, chambered for the .204 Ruger bullet. So far only these rounds have gone through the rifle (36).



Is this a problem with headspace or something else? I will be reloading these cases myself once I have fired all of them, but was wondering if this is a problem with the rifle, and/or should I be taking it back to where I bought it for exchange or not?

[foxwhistler]

A quite likely reason is an oversize fireing pin hole.I have the same problem with my Remi.Best to talk to the dealer you got it from.Just my opinion and more experianced members may think differently.

[acloco]

Or too generous of chamber/headspace.

Or, that ammo is too hot for your rifle.

[Cadeuses]

A quite likely reason is an oversize fireing pin hole.I have the same problem with my Remi.Best to talk to the dealer you got it from.Just my opinion and more experianced members may think differently.

I'll have to give a call to the dealer, Pud at Bashaw Sports to let him know what is happening.

[Cadeuses]

Or too generous of chamber/headspace.

Or, that ammo is too hot for your rifle.

I was kinda thinking headspace problem also. I wouldn't think factory ammo would be too "hot" for a brand new rifle though? I will see if I can get some better pictures at work to focus on the rounds a little closer.

[Rick in Oregon]

Any one of the three explanations could be correct; all good advice. Just to settle the issue, I'd take it to your local smith, have him check the headspace, then mic the firing pin hole in the bolt in comparison to the firing pin diameter. It's unlikely (but remotely possible) that the factory loads are too hot for the rifle.

Remmy's of late seem to have a bit of primer blanking (the correct term for cratering) issues due to what appears to be an overly large firing pin hole. My just completed custom Remmy 204R shares this anomoly too, as the loads are perfectly safe, but all exhibit slight blanking of the primers (Rem 7-1/2's). The fix is to bush the bolt, but you probably don't want to put money into a brand new rifle, and I don't blame you one bit. But it's most likely bush or exchange, but you may end up with the exact same issue on the next rifle too.......

If you can live with it, and the rifle comes back with acceptable headspace (as it probably will), it's really not a big deal unless you start to see gas escaping, then you'll get gas cutting on the bolt, but it's not likely. Just use the thickest cup primers you can find to minimize the issue when you start to reload for the rifle if you decide to keep it.

[Cadeuses]

Any one of the three explanations could be correct; all good advice. Just to settle the issue, I'd take it to your local smith, have him check the headspace, then mic the firing pin hole in the bolt in comparison to the firing pin diameter. It's unlikely (but remotely possible) that the factory loads are too hot for the rifle.

Remmy's of late seem to have a bit of primer blanking (the correct term for cratering) issues due to what appears to be an overly large firing pin hole. My just completed custom Remmy 204R shares this anomoly too, as the loads are perfectly safe, but all exhibit slight blanking of the primers (Rem 7-1/2's). The fix is to bush the bolt, but you probably don't want to put money into a brand new rifle, and I don't blame you one bit. But it's most likely bush or exchange, but you may end up with the exact same issue on the next rifle too.......

If you can live with it, and the rifle comes back with acceptable headspace (as it probably will), it's really not a big deal unless you start to see gas escaping, then you'll get gas cutting on the bolt, but it's not likely. Just use the thickest cup primers you can find to minimize the issue when you start to reload for the rifle if you decide to keep it.

Thanks for the info Rick. I was able to get some super fine macro shots of the heads done at work, and will post them as soon as I can get them into photo bucket. I believe the firing pin may be the culpret in this case. If it can be fixed, it will be done against the Remington warranty, if it was manufactured too small.

Is there any danger of primer failure? I would rather not experience blowback from the rifle! Cheers.

[Rick in Oregon]

Cadeuses: There is always a possible potential, if not very likely degree of primer failure, which I'm guessing you mean blowing apart and allowing gas to blow back through the bolt and action.

In my M700 Varmint in .22-250, I've had Rem 7-1/2's blow apart and pieces of the primer were found INSIDE the bolt mixed into the firing pin spring. Good gas relief prevented any gas from reaching my pretty face, but it's always a possibility, hence the good advice to always wear shooting glasses (which I seldom do, but should).

Hot weather can elevate this possibility too, which is why you should always keep your ammo in the shade, or better yet, in a cooler completely isolated from the outside ambient temperature when out in the varmint patch.

Glad you've found the problem, and good that it will fall under warranty.

[futuretrades]

Hot weather can elevate this possibility too, which is why you should always keep your ammo in the shade, or better yet, in a cooler completely isolated from the outside ambient temperature when out in the varmint patch.

i found out the hard way what effect hot weather has on loaded ammo. when you see smoke coming out of the bolt pressure relief ports, and almost can't open the bolt, you have a bad problem. this happened to me when working up loads for my 223. and i was shooting some loads that i had shot just a week before, when it was 20 degrees cooler, with absolutely no problems. and the loads were almost 1 full grain below max. pierced the primers and pushed pieces of the primers into the firing. after i got the bolt open and tried another round, i could not get the gun to shoot again. at that time, i didn't have any idea what had happened, until i checked with my smith. and showed him the empty. he just about craped silver nickels. i learned the hard way about keeping ammo in an ice chest, especially in hot weather.

[Cadeuses]

Ok, I was able to get better pictures at work that will likely shed better views for all to see. Here they are:

First the Winchester case:



Now the Hornady case:



and lastly the Remington case:



All three:



Here are some cases neck and shoulder pictures for comparison. I could not see any difference between the fired and non-fired factory rounds.





and one last picture:



My vote still goes to small firing pin diameter compared to the bolt face hole size. I sent this to Remington as well to see if they will correct the problem under the warranty, which they should. Cheers.
Dave

[Silverfox]

Dave--If Remington won't cover this under warranty, then I'd suggest you contact Greg Tannell of Gre-Tan Rifles. I had him bush the bolts on both my .17 Remingtons and turn down the firing pin a wee bit. He does a super job, very reasonable on price and he gets your bolt back to you in a hurry!!! He charged me $50.00 plus $7.50 shipping and handling back on May 12, 2006.

Gre-Tan Rifles
29742 W.C.R. 50
Kersey, CO 80644
Phone: 970-353-6176
E-Mail: greg@gretanrifles.com

He isn't real quick at answering e-mails, so be patient. A phone call would be a better method to contact him than e-mail. Here's a link to his Web site. The prices at the Web site are from 2005, so you might want to call him to check on that. Also, it is a good idea to call him to let him know you are sending in your bolt and see if he has any special instructions for you to follow.

http://www.gretanrifles.com/

[jo191145]

I'm no gunsmith by any stretch of the imagination but I've cratered plenty of primers in my 204 and pierced a few.
I must say those are some of the ugliest craters I've ever seen.
Judging by the large outside circumference of the crater I'd put my money on an extremely over sized firing pin hole in your bolt head.

Insufficient firing pin protrusion and the radius of the pin head itself can create cratering problems also.
Nonetheless I'd say you need that bolt bushed!!

[Bayou City Boy]

Just a comment....

Primer cratering is not the same as primer blanking. In recent years, the two have been used interchangeably on the Internet, but technically there is a significant difference.

Primer cratering is defined by SAAMI as "A circumferential rearward flow of metal surrounding the indentation of a firing-pin in a fired primer cup."

Primer blanking as defined by SAAMi occurs when you have "A fired primer cup in which the firing-pin indent has been punched out by internal gas pressure."

In other words. a "blanked primer" is actually what we might typically call a "pierced primer". But, by SAAMI definition, a pierced primer is "A fired primer which has been perforated by the firing-pin."

So, from a true technical point of view a "blanked primer" has been burnt through from the inside by excess internal pressure . A "pierced primer" has a hole in it caused by a defective (maybe too long or sharp) firing pin and the hole is induced by outside influences and not by internal gas pressure.

As a result, the cause of the primer "burn through" (as we typically call it) determines whether a primer has actually blanked or has been pierced.

And a cratered primer has no hole in it... so it is neither a blanked or pierced primer by SAAMI definition.

Where the term "blanking" comes from is that in the technical process of making primers, the cup as we typically refer to it is called a blank.

-BCB

[Rick in Oregon]

BCB: Piercing/Blanking....I stand corrected. Thanks as always for the detailed clarification.

[Bayou City Boy]

BCB: Piercing/Blanking....I stand corrected. Thanks as always for the detailed clarification.

And I need to correct and add a little more, too, Rick.

What I posted above was dealing with small primers like we use in our varmint/predator rifles.. In just about all cases in our world, when a primer blanks, it burns through. In larger impact primers like used in older and large artillery, primer "blanking" sometimes occurred without burning through the larger primers. But it indicated excessive internal pressure even if the primer dent was just "ironed" flat on the artillery breach. Most large artillery today uses electric primers and the problem is no longer an issue.

Today, in small rifles, its typically going to be seen as a burnt primer caused by internal pressure as the cups typically give way in the primer indent when internal pressure flexes the hot thin primer cup material.. A weak firing pin spring often contributes to primer blanking in small caliber rifles.

Today's primer cratering is generally related to other issues, both intentional and accidental results of various rifle manufacturing processes.

Anyway......... I wasn't trying to correct anyone. Just trying to provide a little more information. And I didn't get that done very well the first time.....

-BCB