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Discussion Starter · #1 ·
I've been shooting Pakistani (POF) and Turkish (MKE) surplus and noticed that all of my primers are cratered. The POF is Berdan primed and the MKE is Boxer.


I'm running a stock Springfield Scout/Squad. Factory headspace is 1.631. Roughly 400rds fired through barrel. I clean it after each shooting session (20-40rds per session).

The cratering has been present from round one.

Should I worry?
 

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Can you give us a case length of an unfired cartridge, or several for average ? Just the case , not the projectile or OAL.
 

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I'm curious as to whether we are starting to see something that may become more common; maybe a combination of over sized firing pin hole in the bolt face and soft primer material.

I read recently that one manufacturer (Remington?) is supposedly doing this as a designed safety feature. The idea is that any gases that might escape through a pierced or loose primer can not shoot through the bolt and in to the receiver because the primer cup material blocks the firing pin hole.

I don't know if it's true or not but I do know that we are starting to see more questions from shooters about these kinds of "pressure" marks.
 

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I have No Idea what cause those . This Much I will Say. That/They are Not Right.
Perhaps you could try another Milsurp ammo see if it gets better or the same
 

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Wow! Yeah......that ain't right.
 

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Lots of great responses so far, But what you have is a classic case of "puddling". Surplus ammo that is most likely loaded up past SAAMI spec. It's definately a sign of pressure, that is for sure. The firing pin hole oversize thing doesn't make sense, atleast not in this case (M1A). You would get pierced primers for sure and more problems, firing pin stuck/broken, especially after 400 rounds. I would get a couple boxes of factory ammo, like WWB 147gr, AE 168 OTM, closest to Lake City as you can get (steel, boxer, crimped primer). Try different MFG's and bullet weight and types. I also notice that those are brass primers, softer than steel, and might be another cause of this issue. How does the bolt face look? Scored? Excessive carbon? Discolored purple/blue (overstress)?


MC1 Semper Fi.
 

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Discussion Starter · #8 ·
Thanks, all, for the responses.


Looks like you might have an oversized firing pin hole on the bolt face. Can you snap a picture of that?
It looks fine to me. Hard to get a good photo. There's little to no slop in the firing pin.


Can you give us a case length of an unfired cartridge, or several for average ? Just the case , not the projectile or OAL.
Forgive my low grade field caliper. The good one is in my shop on the other side of town. I'll measure again with it later, but to my eye the cases look to be 2.01"±.002. Strangely, there's not a significant difference between the fired and unfired cases.


How does the bolt face look? Scored? Excessive carbon? Discolored purple/blue (overstress)?


There's that primer shaped ring in the photo at top, which is discoloring of the parkerization. The green stuff in the photo above is primer sealant from the MKE (I'm out of brake cleaner).

Literally the only pressure signs I'm seeing are the primers. The case rims look fine. The only damage to them is on the face of the rim from the extractor snapping on to the rim. There is no bruising from the ejector. The cases are not bulged.

The rifle cycles flawlessly. The brass ejects forward to my 02:00 about 3ft, if I'm shooting from a seated position. It goes 2ft when I shoot prone.

The only stoppage I've had is one case that got caught in my ProMag PM081a optic mount.

Accuracy has been ~2-3MOA with this ammunition, shooting from a bipod.

I believe 1.631 is a bit of a tight chamber. I'm thinking that may be the source of the issue- less room for the case to expand puts more pressure on the primer.
 

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I've had high pressure in commercial bolt actions with tight chamber and military ammo. By a tight chamber I don't mean the headspace. I mean the diameter, especially at the neck of the case. With thicker military brass the chamber doesn't allow the neck to expand enough and it "pinches" the bullet. The other thing can be the throat of the chamber. A longer headspace can band-aid these problems. The chamber throat has more influence on pressure than headspace though. A military chamber has a longer throat compared to a commercial chamber. Try some full power commercial ammo and see if it is still shows high pressure. The other thing is military ammo is usually loaded close to maximum pressure and commercial ammo is often loaded a bit under maximum pressure.
 

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Here is a photo of my bolt face. It appears that yours has been chamfered out or something. You can tell since the distance from the edge of the firing pin hole to the ejector is quite a bit shorter on yours. Not sure how that happened, though.

I do notice that primers on some berdan NATO DAG I have are pretty soft, they tend to flatten out more than my handloads of average pressure.
 

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Here is a photo of my bolt face. It appears that yours has been chamfered out or something. You can tell since the distance from the edge of the firing pin hole to the ejector is quite a bit shorter on yours. Not sure how that happened, though.

I do notice that primers on some berdan NATO DAG I have are pretty soft, they tend to flatten out more than my handloads of average pressure.
You beat me to it...GI2

I was going to point out the same thing.

Your bolt face


Mine


Oh, and with that tight head space dimension (1.631") there is less free space for the the brass to flow and move so that just causes the primers to be pushed even harder in to the bolt face so I believe that the primer cups are being swaged in to that chamfer depression.
 

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Great minds think alike! GI6

This does look like something I would send back to Springfield to fix. It'll probably need a new bolt, and hence need to be headspaced, so the whole barreled receiver or whole rifle will need to go with it. It may be a matter of time before one ruptures and starts welding the bolt face.
 

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Thanks, all, for the responses.




It looks fine to me. Hard to get a good photo. There's little to no slop in the firing pin.




Forgive my low grade field caliper. The good one is in my shop on the other side of town. I'll measure again with it later, but to my eye the cases look to be 2.01"±.002. Strangely, there's not a significant difference between the fired and unfired cases.





There's that primer shaped ring in the photo at top, which is discoloring of the parkerization. The green stuff in the photo above is primer sealant from the MKE (I'm out of brake cleaner).

Literally the only pressure signs I'm seeing are the primers. The case rims look fine. The only damage to them is on the face of the rim from the extractor snapping on to the rim. There is no bruising from the ejector. The cases are not bulged.

The rifle cycles flawlessly. The brass ejects forward to my 02:00 about 3ft, if I'm shooting from a seated position. It goes 2ft when I shoot prone.

The only stoppage I've had is one case that got caught in my ProMag PM081a optic mount.

Accuracy has been ~2-3MOA with this ammunition, shooting from a bipod.

I believe 1.631 is a bit of a tight chamber. I'm thinking that may be the source of the issue- less room for the case to expand puts more pressure on the primer.
Where did you get your bolt? Is it USGI?

If it is USGI and of recent purchase I am wondering if it is a reconditioned drill rifle bolt. I don't know of any other reason someone would need to ream out the firing pin hole. But I will defer to the more knowledgeable crowd here for answers, as I do not have nearly as many years experience with the M14.
 

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You need a new bolt. If it's a SAI bolt, you need to at least inform them of the problem.

I personally wouldn't send the rifle back to SAI to get it fixed. I would buy a USGI bolt, pay way too much for it, and have a smith install it on my dime, and if necessary ream the chamber to provide a headspace of about 1.632".
 

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I agree that the bolt needs to be replaced. I fire lots of MKE with a 1.631 headspace without this type of puddling. I know others who do the same. Just checked about 20 spent rounds of MKE while reading this post and no problems. Another thing I have noticed is that this particular ammo shoots a little soft, less pressure than most other surplus such as South African and RG. I don't think you have a pressure problem with the ammo but an unusual (possibly oversized) firing pin hole that's allowing normal pressures to puddled your primers.
 

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Discussion Starter · #16 ·
I agree that the bolt needs to be replaced. I fire lots of MKE with a 1.631 headspace without this type of puddling. I know others who do the same. Just checked about 20 spent rounds of MKE while reading this post and no problems. Another thing I have noticed is that this particular ammo shoots a little soft, less pressure than most other surplus such as South African and RG. I don't think you have a pressure problem with the ammo but an unusual (possibly oversized) firing pin hole that's allowing normal pressures to puddled your primers.
I reckon I will have SAI replace the bolt. I'm not particularly worried about this problem with surplus, but I'm going to begin reloading for this rifle once the pile of spent brass gets big enough. I suspect that with commercial primers I may start blowing holes in them. Not too excited about that.

Thanks all for the replies and help in troubleshooting this.
 
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