Would excessive headspace cause pierced primers and loose primers?

[gunsandgunsmithing]

Wow! That's over pressure.

I respectfully disagree. See my post 17. I see one case that for whatever reason seems a tad hotter than the rest, by flatter(not terribly) primer and maybe just a very faint ejector mark. Hard to tell but the leftover lube and the case and chamber can do that as well because of more bolt thrust. The rest of the primers are still very rounded and no other signs of pressure either. Again, pressure is rarely the cause of cratering and unless you have other signs of pressure along with it. I don't consider cratering a reliable pressure sign alone. There are other more reliable signs that I don't see in his cases. Savage and Remingtons are both very prone to cratering primers and softer primers show it more easily. In his case, the harder primer stopped the cratering, as would bushing the fp hole.

I will say that when in doubt, err to the side of caution but from what I can see from the pic he posted, I would not be overly concerned, especially since a harder primer seems to have cured his ail.

Savage's issue is similar but a little different than Remington's. The fp fit is somewhat better on the savage but not ideal. I've fixed the issue of savage craters by simply truing up the bolt head/face. They have a slight concave around the pin hole, not quite as big around as a small primer, that allows the primer to stretch and weaken a tad and promote cratering. Just making the bolt face very flat stopped the cratering on more than a few savages that I've worked on in this very regard, fwiw. You very easily see the dishing of the bolt face while truing it up. Some are worse than others. I had one that I was gonna post a pic of but it cleaned up fast and the evidence is now gone on that one, in under .002...but some are very clear. I don't have another or I'd do it because sometimes a pic is worth 1000 words.It just left a "shadow" of what I'm talking about and it doesn't show up in my picture hardly at all. I'm sure other smiths have seen it if they do any savage action truing.

 

[M-61]

Cleaning that lube off those cases will probably result in a more consistent shooting rifle. Cases have trouble gripping the chamber wall if lube involved.

Very dangerous leaving any lube on a case. Bolt thrust goes through the ceiling, hopefully, and not through your cheek.
Check British Armory methods of proofing actions.

 

[M-61]

When fired, case gets pushed forward, primer tries to back out, gets pierced and or flattened.
Usual cause? Shoulders got pushed back too far

Primer does back out. If the headspace is correct it’s an insignificant amount.
So tigger pull
Firing pin travels down bore in bolt
Strikes primer moving the case forward to the datum line
Primer explodes
Powder ignites
Bullet starts on its trip in the barrel
Case expands grasping the chamber walls (No Lube Ever)
Primer starts to leave pocket
Brass cases springs back from chamber walls and brass smashes back to the bolt face and primer is basically re-seated sometimes flattening the primer. ( flattened primers are not a sign of excessive pressure) nor are cratered primers. Cratered primers occur, generally, because the bore in the bolt is a bit too large. If you couple this with a weak firing pin spring and you can have a pierced primer especially with a somewhat hotter load.
As you might see ‘bumping’ the shoulders an arbitrary amount is rally hard on the brass. You’re working the brass needlessly. You can't bump’ anything on a headspace gauge!
I switch barrels like crazy and never had a problem. I torque the to 45 lbs ft. Have never had a nut move much less a barrel loosen. A slight wipe of antiseze ( doesn’t stop me for putting a register mark them, but that’s me.
Maintaining the correct headspace as you tighten the jam nut is a bit of a pain. Seems after I do it I have to re-do it again ( always rechecking when I am done) three hands would be nice. That torquing of the jam nut loves to move the barrel.
Wonder how much of say 52,000 psi is divided up. % to move bullet, % to expand case, % to push case back etc. Just wondering nothing of any vital importance as you can nothing about it anyway.
Everything I’ve written is my idea of how things work on my rifle.

 

[David Milisock]

I respectfully disagree. See my post 17. I see one case that for whatever reason seems a tad hotter than the rest, by flatter(not terribly) primer and maybe just a very faint ejector mark. Hard to tell but the leftover lube and the case and chamber can do that as well because of more bolt thrust. The rest of the primers are still very rounded and no other signs of pressure either. Again, pressure is rarely the cause of cratering and unless you have other signs of pressure along with it. I don't consider cratering a reliable pressure sign alone. There are other more reliable signs that I don't see in his cases. Savage and Remingtons are both very prone to cratering primers and softer primers show it more easily. In his case, the harder primer stopped the cratering, as would bushing the fp hole.

I will say that when in doubt, err to the side of caution but from what I can see from the pic he posted, I would not be overly concerned, especially since a harder primer seems to have cured his ail.

Savage's issue is similar but a little different than Remington's. The fp fit is somewhat better on the savage but not ideal. I've fixed the issue of savage craters by simply truing up the bolt head/face. They have a slight concave around the pin hole, not quite as big around as a small primer, that allows the primer to stretch and weaken a tad and promote cratering. Just making the bolt face very flat stopped the cratering on more than a few savages that I've worked on in this very regard, fwiw. You very easily see the dishing of the bolt face while truing it up. Some are worse than others. I had one that I was gonna post a pic of but it cleaned up fast and the evidence is now gone on that one, in under .002...but some are very clear. I don't have another or I'd do it because sometimes a pic is worth 1000 words.It just left a "shadow" of what I'm talking about and it doesn't show up in my picture hardly at all. I'm sure other smiths have seen it if they do any savage action truing.

The foreground right, just behind that out of focus and the two to the left in the foreground certainly show signs of distress.

The one in the middle second from the front out of focus is another one that shows issues.

If this were me the first thing I'd do is check the accuracy of the go/no go guages.

 

[M-61]

If this were me the first thing I'd do is check the accuracy of the go/no go guages.

Interesting thought. How would one do that?

 

[gunsandgunsmithing]

The foreground right, just behind that out of focus and the two to the left in the foreground certainly show signs of distress.

The one in the middle second from the front out of focus is another one that shows issues.

If this were me the first thing I'd do is check the accuracy of the go/no go guages.

The one lower right is the one I was referring to as well. Excess headspace, as in new brass for example, and/or lube still on the case or chamber can do that too. I don't see an issue with the other case as the primer edge is still very rounded. Just my opinion but I mentioned the basis for it already. Sounds like a harder cup fixed his immediate issue with cratering so no need hashing it out much. Hell, you might be right but that's why my opinion is what it is. Again, nothing wrong with erring to the side of caution, though.

 

[David Milisock]

The one lower right is the one I was referring to as well. Excess headspace, as in new brass for example, and/or lube still on the case or chamber can do that too. I don't see an issue with the other case as the primer edge is still very rounded. Just my opinion but I mentioned the basis for it already. Sounds like a harder cup fixed his immediate issue with cratering so no need hashing it out much. Hell, you might be right but that's why my opinion is what it is. Again, nothing wrong with erring to the side of caution, though.

The problem with troubleshooting is that you need to check everything, starting with the measurement tools. In the case if the guages are good, then possibly the barell was headspaced wrong when the load was done.

Forty years ago I took over as plant manager at a 50 man print shop. Finishing was all over the place, I gathered up every line guage in the plant and checked them, I tossed 20 of them and had to buy 60 to find enough that messed the same.

Some of the staff measured 1 and 11/32 as 1 and a quarter and then a bit!

 

[gunsandgunsmithing]

The problem with troubleshooting is that you need to check everything, starting with the measurement tools. In the case if the guages are good, then possibly the barell was headspaced wrong when the load was done.

Forty years ago I took over as plant manager at a 50 man print shop. Finishing was all over the place, I gathered up every line guage in the plant and checked them, I tossed 20 of them and had to buy 60 to find enough that messed the same.

Some of the staff measured 1 and 11/32 as 1 and a quarter and then a bit!

Not sure if you intended that for me or not but I totally agree. You certainly can't measure better than the tools you are using to measure with.

 

[DShortt]

Still waiting for someone to explain how a headspace issue can result in loose primer pockets.

That's a neat trick I don't want to learn.

 

[David Milisock]

Not sure if you intended that for me or not but I totally agree. You certainly can't measure better than the tools you are using to measure with.

It's a common malady in any technical field. In my profession I have to listen to the modern professional explain to my why the color on their iPhone is correct and my $7,000 color managed system in a light controlled studio is wrong. Go figure.

 

[DShortt]

It's a common malady in any technical field. In my profession I have to listen to the modern professional explain to my why the color on their iPhone is correct and my $7,000 color managed system in a light controlled studio is wrong. Go figure.

So I'm genuinely curious as to how someone proposes to qualify the dimensions of a headspace guage.
If you're gonna go down that road you need to be better than the manufacturer. So how do you propose to do so?

I could offer several suggestions but they all aren't accurate enough to qualify a measurement standard.

I'd like to see someone chime in with a valid method for qualifying a chamber gauge.

 

[M-61]

headspaced wrong when the load was done.

Lost me.

 

[gunsandgunsmithing]

So I'm genuinely curious as to how someone proposes to qualify the dimensions of a headspace guage.
If you're gonna go down that road you need to be better than the manufacturer. So how do you propose to do so?

I could offer several suggestions but they all aren't accurate enough to qualify a measurement standard.

I'd like to see someone chime in with a valid method for qualifying a chamber gauge.

Why not just an optical comparator? The hard part would be establishing exactly where the datum diameter is, to measure from, I would suppose. I do agree in principle that verifying something is roughly twice as hard as actually doing it.

 

[M-61]

the case head never actually comes in contact with the bolt face

That’s an interesting scenario.
I don’t see that as possible. If the case never hit the bolt face you would extract a case in which the primer would be sticking out. ( you could measure that and get your headspace. )Same as placing a primer just n the flash hole in an empty case and closing the bolt. What’s sticking out is roughly your headspace.
Since the OP has a pierced primer problem I’m still looking for a reason how headspace plays a part in that.

 

[M-61]

Hard to tell but the leftover lube and the case and chamber can do that as well because of more bolt thrust

If you have lube on the case you either don’t realize the potential danger or your working in a British proofing lab.

 

[David Milisock]

Lost me.

The original poster said that he had removed the barrel and reset it. At least that's how I remember itl

 

[David Milisock]

So I'm genuinely curious as to how someone proposes to qualify the dimensions of a headspace guage.
If you're gonna go down that road you need to be better than the manufacturer. So how do you propose to do so?

I could offer several suggestions but they all aren't accurate enough to qualify a measurement standard.

I'd like to see someone chime in with a valid method for qualifying a chamber gauge.

The same way a manufacturer checks them when they manufacturer would be a start.

 

[DShortt]

The same way a manufacturer checks them when they manufacturer would be a start.

So how precisely do they do that?

I honestly don't know. Again, I could offer suggestions but everything I can think of introduces variables that are difficult to account for at best.

 

[DShortt]

Headspace is an interesting scenario because we're dealing with a datum line on an angle. If there's a simple way to deal with that situation I'm all ears because frankly I can't conceive a simple solution.

Keep in mind we're discussing qualifying a standard here. The datum line has to be perfect. The angle has to be perfect.
Close just doesn't cut it.

And perhaps the elephant in the room is how does this REALLY relate to the OPs issue?

 

[gunsandgunsmithing]

That’s an interesting scenario.
I don’t see that as possible. If the case never hit the bolt face you would extract a case in which the primer would be sticking out. ( you could measure that and get your headspace. )Same as placing a primer just n the flash hole in an empty case and closing the bolt. What’s sticking out is roughly your headspace.
Since the OP has a pierced primer problem I’m still looking for a reason how headspace plays a part in that.

Pierced or cratered..doesn't really matter but, hs can do it for the reasons I mentioned in past 17, iirc. The case slams back against the bolt face and the pin can momentarily back out..or bounce, leaving the primer unsupported and free to flow into the fp hole, similar to too much pin hole clearance. Weak spring can cause it for the same reason