R700 5R .223 cratered/blown primers with factory ammo

Gentlemen,

I'm having some serious issues with my 5R in .223 with factory ammo. All this rifles has seen is factory ammo (my first rifle incidentally), approximately 600 rounds worth.

To get right to the point here, I shoot this rifle infrequently so this issue is about 3 years and ~200 rounds in the making.

Right off the hop i'd like to admit fault. When I started to notice funniness with the primers I knew something was up but didn't take action and just let things play out while I observed. The major reason being the load that started the trouble were Sako Gamehead 55gr. soft points and the accuracy they were giving me was phenomenal. At 100 yards rounds were going into the same hole and I was consistently shooting .25 MOA groups. This was far in excess of any accuracy I had previously been able to achieve, and especially with buddies around to impress the temptation to continue to use that load made me complacent. This was before I had started to reload at all, one would hope i'd know better now. Not proud of this but no ego, just the facts.


Before I had shot the Sako I had shot about 400 rounds of assorted factory ammo over a few years, mainly cheap stuff because I was just getting into shooting (winchester white box mainly, some American Eagle), but moving into more premium ammo like Hornady and Nosler as I progressed. Looking back through all my brass from that period it all looks fine, I was having intermitent problems with light primer strikes with some of it right from the beginning but it was sporadic and they all went bang the second time through.

The issues started with the Sako (rounds not presented in order shot, they were all picked up later);


https://i.imgur.com/sN4IoXO.jpg


https://i.imgur.com/ipgklVX.jpg




The rounds all functioned and fired fine. Extraction was nice and smooth, other than the primers nothing out of the ordinary on the brass and while in retrospect some of those primers are clearly pierced I there was no gas blow by felt or seen.


In between shooting some of the Sako, I shot some Hornady V-MAX 55gr. The primers on those appeared fine, although upon closer examination now a couple of them at least were slightly cratered (placed bottom left);


https://i.imgur.com/GdEyYwl.jpg



The real concern started when I brought this rifle out again (after a year or so) to ring some steel with some generic .223 ammo. I got a couple rounds off, and initially after examining my first three cases or so quickly the primers looked OK. And indeed, a few brass out of this batch do look OK. I then proceeded to shoot most of the rest of two boxes pretty rapidly when I noticed smoke leaking from around the bolt after a shot. Upon extracting it I noticed the primer was pierced, and examining the brass that was strewn about I noticed that a few other primers (4!) were pierced and most of the rest of them were cratered/bulging. I only had three rounds left in the box at that point, so I didn't shoot those.


https://i.imgur.com/BDyLx7Z.jpg

https://i.imgur.com/oDJqFq4.jpg




I did however shoot some other Hornady Varmint Express (40gr.) I had lying around, and while not pictured those primers looked perfectly fine.
Also included for your consideration is some Hornady Superperformance I shot before and during the above events (i'm not sure which box is which, both pictured), and some Winchester Whitebox from way back.


https://i.imgur.com/tD196uZ.jpg


https://i.imgur.com/48XL3Io.jpg


https://i.imgur.com/j9PH2ae.jpg






My questions are what likely originally happened/could have happened to start off the issues, what happened when I continued to shoot the rifle, and what needs to be done now to correct the problem.
Here are a couple pics of the bolthead;


https://i.imgur.com/ysVui94.jpg

https://i.imgur.com/kUbqUCS.jpg





What are everyone's thoughts on this? Other than the fact that i'm a moron, I know that (although you can still tell me that if you want).

Bad firing pin?

The boltface was a bit dirty in the first set of pictures, here is it after a quick swab with some Hoppe's;

https://i.imgur.com/fI3hvqd.jpg


And just a (old) picture of the rifle in question;

https://i.imgur.com/yPf6uzq.jpg

Getting into shooting I thought long range competition would be what i'd want to get into. Instead all I do now is cast for my milsuprs and shoot them mainly off hand. Actually haven't had this rifle out in quite a while, and not just because I need to get to the bottom of what's going on.

The excessive pressure signs could be bad fouling or desperate need of cleaning the bore, an oversized firing pin hole or a barrel with out-of-spec chamber or bore diameter on the small side.

A thorough cleaning would alleviate the potential fouled-bore issue.

Slugging the bore would reveal whether or not the barrel itself is smaller diameter than SAAMI spec.

A chronograph of various factory rounds would reveal if the pressure was indeed very high and eliminate the potential oversized firing pin hole.

A bushed firing pin hole to reduce the potential for blanking the primers would help the cratering but not the potential over pressure itself.

Light primer strikes could be from a number of potential issues: weak firing pin spring, short firing pin protrusion, improper cartridge headspace, improper chamber headspace just to mention a couple.

Handloading with likely "fix" any pressure issues as you would be in control of the chamber pressure and cartridge dimensions.

A call to Remington might have them take a look at it. They might not return it to you in a manner that you like (install the new lawyer trigger). Might even just replace the whole thing outright and the accuracy dice will be rolled again.

You've got a few options to pursue.

Too much info here. Short response: get a new firing pin.

Quote:

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Originally Posted by CastingFool

Bad firing pin?

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Quote:

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Originally Posted by NSB

Too much info here. Short response: get a new firing pin.

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Too much info is a bad thing? I've got time.

What exactly are the potential issues I could be having with the firing pin that could lead to these issues? Like I mentioned, this rifle did have intermittent issues with light strikes with some ammo.

I took the bolt apart, here are some pictures of the firing pin. The tip has it's factory chamfer, to my mind the tip doesn't seem to be damaged. However it does have some galling on the firing pin about about .080 forward of the flat. It's shiny all the way around and there's some galling where it's been contacting something.
I'm not sure where to firing pin is designed to contact to stop on the 700, anyone have any insight?

https://imgur.com/n9EXNL0.jpg


https://imgur.com/sKdfCWg.jpg


https://imgur.com/sKdfCWg.jpg


I did find one circular piece of brass lodged somewhere in there while I was cleaning.

Quote:

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Originally Posted by McFred

The excessive pressure signs could be bad fouling or desperate need of cleaning the bore, an oversized firing pin hole or a barrel with out-of-spec chamber or bore diameter on the small side.

A thorough cleaning would alleviate the potential fouled-bore issue.

Slugging the bore would reveal whether or not the barrel itself is smaller diameter than SAAMI spec.

A chronograph of various factory rounds would reveal if the pressure was indeed very high and eliminate the potential oversized firing pin hole.

A bushed firing pin hole to reduce the potential for blanking the primers would help the cratering but not the potential over pressure itself.

Light primer strikes could be from a number of potential issues: weak firing pin spring, short firing pin protrusion, improper cartridge headspace, improper chamber headspace just to mention a couple.

Handloading with likely "fix" any pressure issues as you would be in control of the chamber pressure and cartridge dimensions.

A call to Remington might have them take a look at it. They might not return it to you in a manner that you like (install the new lawyer trigger). Might even just replace the whole thing outright and the accuracy dice will be rolled again.

You've got a few options to pursue.

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Thanks for the detailed response McFred.
Can lack of cleaning really be causing the problems? I'm open to all possibilities and that's an easy one to rule out. I haven't actually cleaned this barrel out since I started shooting the rifle, I lacked a high quality rod that would fit when I first got the rifle and I didn't want to do more harm than good superstitiously cleaning it. 600 rounds later I could be due, but I was waiting for accuracy to drop off before I messed with it. It doesn't appear to be full of copper from looking at it, actually it looks pretty clean in general.

Start with a new firing pin spring and possibly a new firing pin. I'm not seeing excess pressure with some of the pierced primer loads, more of a poor/sloppy finding pin fit in the bolt face. That is a known cause of cratered primers in normal pressure loads. If the firing pin spring is weak, the combination could cause pierced primers with normal pressure loads.

So I'd start with a new spring and see if that fixes the problem.

Have you called Remington yet? That would be my first step. If they want you to send the rifle back(which is probably what they will do) send a couple of the cases with blown primers along with it. my advice anyway, james

I'd also clean it. Then look and see if there is any copper build up. I use a small magnifier and good light at the muzzle (not a light from the breech). Get a one piece rod (I don't spend a fortune on them), a bore guide (the kind that fits in the receiver) and a muzzle guide (it centers the rod in the bore guide). I do not like stainless steel cleaning rods.

But, I agree with above that the loads do not look over pressure to me and the firing pin/spring may be to blame.

FWIW, my Savage in .223 always craters the primers. Never pierced one. Never got a light strike.

The piece of brass that you got out might have caused the light strikes. It looks like only the PPU rounds pierced and only five of them so it may be a bad lot of ammo. It needs to be figured out because it's a SHOOTER obviously.

Sent from my SAMSUNG-SM-G930A using Tapatalk

Firing pin spring is weak or the hole is too large.

Quote:

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Originally Posted by Texas by God

The piece of brass that you got out might have caused the light strikes. It looks like only the PPU rounds pierced and only five of them so it may be a bad lot of ammo. It needs to be figured out because it's a SHOOTER obviously.

Sent from my SAMSUNG-SM-G930A using Tapatalk

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Light strikes had been occurring since I first started shooting the rifle, long before any of this started. It won't reliably ignite American Eagle particularly, I had bought a bunch just for setting off tannerite and maybe 1/3 would fail to go off the first time.

If you look closely, 6 of the Sako had the primer punched through and you can see the resulting disk still inside the primer cup. The PPU did blow that disk out. I shot the same PPU through a semi auto with nothing out of the ordinary occurring.
I think we can all agree the primers are VERY cratered though in the case of both the PPU and the Sako, not just cratered but actually protruding out into the firing pin channel.

Quote:

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Originally Posted by charlie b

I'd also clean it. Then look and see if there is any copper build up. I use a small magnifier and good light at the muzzle (not a light from the breech). Get a one piece rod (I don't spend a fortune on them), a bore guide (the kind that fits in the receiver) and a muzzle guide (it centers the rod in the bore guide). I do not like stainless steel cleaning rods.

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I'll probably get a tipton carbon fiber rod, I have one that does 27-45cal and I rather like it. The bore guides i'm iffy on. I have one for larger caliber I don't use anymore because the rubber funnel it ends up catching in the receivers on my milsurps on either the bolt catch or the ejector (mausers and k31), and then becomes a massive pain in the rear to remove.

I know benchrest shooters are all about them, but the only ones I can get here are the bore tech and they're $60 plus tax, which as much as the nice tipton rods. So i'm conflicted.

I'll clean the bore since it's an easy thing to rule out, but it really does look quite pristine.

Quote:

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Originally Posted by Peregrine

Can lack of cleaning really be causing the problems?

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If the bore is exceptionally rough, as production barrels can be, it could have collected enough fouling to impede the passage of subsequent projectiles. This additional friction may raise chamber pressures resulting in primer cratering and blanking. It's usually easy to see with a bore scope or bore camera through an otherwise clean bore.

I agree with Texas By God that any debris in the bolt body (bits of brass) may have impeded the pin's movement and may have resulted in light primer strikes. Solvent, a brush or compressed air to clean the bolt out would go a ways to ruling that out. Otherwise go/no-go gauges will also determine if the chamber is not within spec which could lead to misfires as well as a weak firing pin spring, aaaaand the possibility of the firing pin protrusion from the bolt face (which should be about .060" or so).

Pierced primers can and will actually cut the tip of your firing pin just like and oxy acetlene torch will. I have had it happen to me and seen a rem 700 bolt chock full of the pieces of the punctured primers. Took the guys bolt apart and shook it and all the little pieces came out. Tip of the pin was severely gas cut. Hole where the pin went through the bolt was badly damaged from the pieces of brass. There is very little clearance between the firing pin and the hole in the bolt. Those loads with the Sako? brass look to be on the hot side flattened and cratered. I'd say at the minimum you would need a new firing pin. As an aside check the diameter of those sako bullets and use a copper solvent like butch's bore shine. Stuff smells but will remove powder and copper fouling. And if you send the rifle back to rem, don't be suprised if they swap out the old trigger for a new lawyer proof one. Frank

Light strikes could be a sign of long headspace. Same for the primer appearance. The primer backs out with the case forward than get reseated under pressure.

I use this bore guide.

https://www.midwayusa.com/product/34...ith-delrin-tip

And this on the rod (centers the rod at the back of the bore guide)

https://www.midwayusa.com/product/66...ber-and-up-rod

Works well. I have also used the cheap MTM one. Both fit my Savage actions nicely.

Measure the protusion of the the firing pin through the bolt .give everything a good clean then try it again it might be OK .a little crud in the wrong place can cause havoc.

I'm seeing the cratered and pierced primer. But don't see a flattened radius on the primers or extractor imprint on the case. Aside from the cratered/blown primer, the pressure doesn't look high. Is the bolt sticky when opened? Try the cheap stuff first, I'd replace the firing pin spring to see if a weak spring is the problem. I'd measure the case head expansion, you should have about .007 increase from new, on a normal fired case.

What is the firing pin extension from the bolt face?

A possibility for the blown primers is the chamber neck is cut a bit short, and/or the factory ammo was not trimmed properly. The case mouth pinching the bullet in place can send pressures sky-high. I would check the case length of the cases with blown and cratered primers, compare to other cases, and post the info here.