What cause my primers to look like this?

[Trevor300wsm]

I'm doing some load work on my 6x47. I'm shooting Lapua brass, Berger 105's, 205M primers, and 38.7gr of 4350.
I've shot this rifle previously, but got the new Bergers and I'm trying different seating depths. I loaded 20 rounds all the same as follows.
5 at .005 off the lands
5 at .008 off the lands
5 at .010 off the lands
5 at .015 off the lands.

I shot the first 10 shots and noticed that out of the 10 pieces of empty brass, 3 of them had some type of primer issue. The other 7 were fine. As you can see in the pic, 3 of them seem to have a "dent", but it's also raised up. The one on the far right is normal and used for comparison. What caused this??

 

[Bradley]

Re: What cause my primers to look like this?

You may need to have your firing pin hole bushed.
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1517320

 

[KHOOKS]

Re: What cause my primers to look like this?

My rifle does this also. By the looks of the primers around the edge at the case it appears it's not a pressure issue. It is the primer being forced and flowing back into the bolt face. If you look at your bolt face you will see that the firing pin hole is oversized more than it has to be. You can have this fixed by ordering a oversized firing pin and hand turning it down until it just passes thru the firing pin hole in the bolt face. Or you can send your bolt off to a smith and they can add to the hole and resize it to the correct size.

As for me I wouldn't worry about it. I Rem. LTR .308 has been like this from new. I have not had any issues with it other than the primers look that the ones you have.

As you work up your charge weight watch of the primer to square off at the edge of the case and not look rolled as they appear now. Also keep in mind how much force you need to open the bolt. If it starts to take more force it my be a sign of high pressure. You will also see the case head get real shiney from where the case is pushed back into the bolt face so hard that it take form of the bolt face.

Edited would to wouldn't (my bad)

 

[Trevor300wsm]

Re: What cause my primers to look like this?

Thanks for the replies. I read and heard about bolts needing to be "bushed" on the 6 and the 6.5, but I didnt know what the outcome was if it was not bushed. Now I do....thanks again.

 

[fw707]

Re: What cause my primers to look like this?

Mine does it too. I get the little dimples all the time, with no other pressure signs at all.
I stopped worrying about it.

 

[fish30114]

Re: What cause my primers to look like this?

Well I wouldn't not worry about it..geez! That is classic primer cratering.

http://www.noslerreloading.com/phpBB2/viewtopic.php?t=11278

Re-shaping the the tip of your firing pin could help, BUT, you did not have this problem prior, so that says pressure!

As you stated, the one on the right was normal. If that is what you got before there is no way that you should start now unless something is amiss. are the first ones you tried the ones that were closest to the lands? That looks like a classic pressure issue to me.

What else is different? did you measure these bullet to the lands distances with a comparator--in other words, I wonder if the ogive is different enough that you are lot closer to the lands than supposed. I don't know how close that charge is to max, but as you probably know, it doesn't matter, every rifle likes what it likes on it's own, and pressure issues can change quickly.

I would proceed with caution, and cypher more data if you have/get it...

Good luck

 

[vman]

Re: What cause my primers to look like this?

Two two primers on the right look like they have flattened a little

 

[Fuzzball]

Re: What cause my primers to look like this?

Try different primers.

 

[ramrod197]

Re: What cause my primers to look like this?

Ive been reloading for 20 yrs ,never seen that in my guns, i would look at my bolt face and make sure the fireing pin isnt coming thru the bolt face.your load isnt too hot bc your primers arnt flat. mite be your primers are too thin, so like the other guy said try other primers

 

[ackleyfan]

Re: What cause my primers to look like this?

What action are you using?

 

[JuniperEyes]

Re: What cause my primers to look like this?

First firing on new brass?

 

[Swan]

Re: What cause my primers to look like this?

Pressure.

Cases toward the end of the string of fire may show more heavily, like the protruding one? Chamber is getting very warm. I have seen this once with my load as well on a 10 shot string during a match.

 

[Trevor300wsm]

Re: What cause my primers to look like this?

Ok,
The only thing that I changed in my load was switching from AMax's to Bergers. Both 105gr pills. Same brass, same powder, same primer. The action is a trued/printed 700. It's had the works done to it by Clay Spencer. I haven't seen any other signs of higher pressure. The load isn't max. I've read that this is common on the 6 and 6.5 calibers. Also, about my chamber getting hot. Well I didn't shoot a string of 10 in a row. They were fired in 3-4 shot groups with plenty of time for things to cool down between each group. I was doing load development so I wanted to make sure excessive heat wasn't an issue to I took plenty of time for cool down. I fired a total of 23 rounds and only 3 showed the protrusion in the primer as pictured. The bolt was not tight upon opening either so I'm not going to worry about it too much. I'll get the bolt bushed and go from there.

 

[buffybuster]

Re: What cause my primers to look like this?

Get the FP hole bushed. This is a fairly common issue with Remington OEM FP holes and Small Primers.

 

[Bradley]

Re: What cause my primers to look like this?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: buffybuster</div><div class="ubbcode-body">Get the FP hole bushed. This is a fairly common issue with Remington OEM FP holes and Small Primers. </div></div>

Exactly!

 

[Mutt]

Re: What cause my primers to look like this?

Out of curiosity: What's with the imprint around the primer pocket? ('tween the edge of the pocket and the top of the headstamp) Is it noticeable on the virgins? I can't see it on the far right one, either...only on the three "suspect" cases.
I wonder what the bolt face looks like? Forgive me, I've just never seen brass imprinted like that before and it has me wondering if there's more to it.

Take care,
~Mutt

 

[Jhnmdahl]

Re: What cause my primers to look like this?

The primers aren't flattened much despite the firing pin craters - suggests it's the firing pin hole and not overpressure.

 

[mac37]

Re: What cause my primers to look like this?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">In the last few years Remington has been designing there 700's to crater primers on purpose. They've added a very very slight bevel to the firing pin hole so that primer cratering occurs during case expansion. This causes the primer metal to drift forward and thicken at the lip of the cratering and the dome of the firing pin strike. The Remington rep said they even have primer cutaways back at the factory that proves it works.
</div></div>

My rifle does the same. Here's what I was told.

 

[JuniperEyes]

Re: What cause my primers to look like this?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: J.S.T. Glenn</div><div class="ubbcode-body">First firing on new brass? </div></div>

Does not look like excess pressure to me. Looks like brass was considerably shorter from base to shoulder than chamber dimensions. This allowed the firing pin strike to drive the case forward in the chamber (especially on the rounds with deeper bullet seating). When the charge ignited, the primer backs out first, hits the bolt face, and then the case stretches untill the face of the brass contacts the bolt driving the primer back into the primer pocket. Thats why the primer crater looks so strange on these in photos. A properly headspaced round will not exhibit nearly as exreme cratering without obvious flattening of Federal primers and will usually show bolt swipe marks on at least some cases.
I may be wrong, but if not unfired brass in the photos, how much shoulder setback do you have your dies set up for?

Just trying to help
Glenn

 

[Greg Langelius *]

Re: What cause my primers to look like this?

Primer brass flow into the gap between firing pin and the firing pin opening in the bolt.

At the apparent pressure levels this is not causing any harm, and bushing the firing pin with solve this.

When it does, the only improvement will be cosmetic; this is not a significant issue. I'd just note the issue and move on, fixing it would likely have no bearing on accuracy, and it's not like those used primers are going to be doing anything important after they are decapped.

Greg

 

[BK7saum]

Re: What cause my primers to look like this?

I have the same issue with my 6x47 lapua. I've never pierced a primer, but have lots of slightly cratered ones. What load or velocity are you getting with 105s? And what powder. I run H4350 with velocities around 2950-2970. No other signs of overpressure. Primer pockets are still tight after several reloads. Primers aren't flattened either. I seat at or slightly into the lands. When I backed the bullets off the lands, the cratered primers quit showing up as bad and as often. Wonder if the small flash hole and/or seating into the lands has anything to do with it?

 

[coldbeerchief]

Re: What cause my primers to look like this?

I had the same problem with my 6.5x47. It was definitely a problem when a primer got pierced. It would do funky things to my Jewel trigger.

Have the bolt bushed and your issue will go away.

 

[vman]

Re: What cause my primers to look like this?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: trevor300wsm</div><div class="ubbcode-body">Ok,
The only thing that I changed in my load was switching from AMax's to Bergers. Both 105gr pills. Same brass, same powder, same primer. The action is a trued/printed 700. It's had the works done to it by Clay Spencer. I haven't seen any other signs of higher pressure. The load isn't max. I've read that this is common on the 6 and 6.5 calibers. Also, about my chamber getting hot. Well I didn't shoot a string of 10 in a row. They were fired in 3-4 shot groups with plenty of time for things to cool down between each group. I was doing load development so I wanted to make sure excessive heat wasn't an issue to I took plenty of time for cool down. I fired a total of 23 rounds and only 3 showed the protrusion in the primer as pictured. The bolt was not tight upon opening either so I'm not going to worry about it too much. I'll get the bolt bushed and go from there. </div></div>

Keep in mind that different brans of bullets have differing amounts of bearing surface which in turn will can have an affect on pressure signs. If your pushing one projectile at the boundaries and then replace it with another same weight projectile, but one with more bearing surface... you may then notice some pressure signs showing up.

 

[joemagee]

Re: What cause my primers to look like this?

Bush that thing..

 

[Grump]

Re: What cause my primers to look like this?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: trevor300wsm</div><div class="ubbcode-body">Ok,
The only thing that I changed in my load was switching from AMax's to Bergers. Both 105gr pills. </div></div>
Please tell me that you at least compared bearing surfaces first!

 

[CK_32]

Re: What cause my primers to look like this?

They look a tad flat. Check your pressures...

 

[Downzero]

Re: What cause my primers to look like this?

All good loads will flatten primers.

I would probably have the bolt bushed, just because I wouldn't want to deal with the primer flow.

I'd consider backing the load down a tad just to see what results.

I'd also try magnum primers and see what happens (back the load down first).