Spent Primers Sticking Out

[ar15barrels]

Originally Posted by focus

I size the case to match the go gauge used to chamber the barrel.
Attachment 709489

Attachment 709490
Cheers,

Do you know exactly how much headspace the chamber has over the GO gauge?

[JackEllis]

Originally Posted by ar15barrels

Knowledge is a wonderful drug.
You are on a good path now.

A brand spanking new Hornady headspace gauge was delivered to my door yesterday afternoon. It's easy enough to use, but you have to be careful to wiggle the case around until you get the smallest reading you can. Canting the case just a tiny bit in the caliper throws off your measurements by a couple thousandths.

What the gauge told me is that I have a bunch of sized .223 cases that are about 6 thousandths longer than they need to be. Not great but within spec (max allowable headspace of .014 according to Randall) and I get groups I can live with (for now). The difference in chamber length between the two rifles is less than a thousandth of an inch, and that's close enough that I can use the same cases in both of my .223s.

[focus]

Originally Posted by ar15barrels

Do you know exactly how much headspace the chamber has over the GO gauge?

I cut my chambers ~1.4 thousands over the go gauge length. I gauge the final cut DRO number that gives a snug bolt closure. The bolt won't close on the go gauge with a piece of scotch tape on the gauge head.

Cheers,

[fguffey]

There was a little nursery rhyme that was made up by a bench rester; it went something like, "the firing pin strikes the primer and then drives the case into the chamber until the case contacts the shoulder of the chamber. And then? the primer ignites the powder?

All it amounted to was memory work, something like a reloader bumping the shoulder back on a press that is not a cam over press. I have presses that are bump presses because they are cam over presses but that is more information than a reloader can handle.

If you are not shooting reduced loads and the case locks to the chamber there should be no way for the primer to protrude from the cases when fired.

The one thing that drives a reloadser to the curb is the part about the case shoulder moving forward when the primer strikes it. When the case locks onto the chamber the case head is driven back with pressure, There is no cute little nursery rhyme for this problem; when the case head is driven back while the case body is locked onto the chamber the case stretches between the case head and case body when the case head moves back when the case stretches the primer is reseated.

SO? Simeone should check to see if the inside diameter of the barrel is too large in diameter, or there is a problem with the powder or the bullet is too small in diameter etc.

F. Guffey

[fguffey]

I cut my chambers ~1.4 thousands over the go gauge length. I gauge the final cut DRO number that gives a snug bolt closure. The bolt won't close on the go gauge with a piece of scotch tape on the gauge head.

I am sure most of the reloaders on this forum pretend to understand your response; When you cut a chamber that is longer than a go-gage from the shoulder/datum to the bolt face you are not cutting a short chamber,

I understand reloaders are infatuated with "HEAD SPACE"; Not me! I understand there are go-gages, there are no-go gages and there are field reject length gages. And then there is the other one, the other one is the case length gage. The case gage measures the length of the case from the datum/shoulder to the case head. For reloaders that can keep up the full length sized cases is a minimum length case.

What does this mean?

If you add .0015" to the length of the chamber from the shoulder of the chamber to the to the bolt face. If you were talking about a 30/06 chamber you would be cutting the chamber with .0065" instead of .005".

Again, I have a 30/06 chamber that is .016" longer than a minimum length/full length sized case, for those that need help keeping up that would be a chamber that is .011" longer than a go-gage length chamber or .002" longer than a field reject length gage. The smith that repaired/inspected the rifle during rebuild/inspection stamped the rifle. He stamped thousands if rifles.

I know, the long chamber worries a lot if reloaders, I form 280 Remington cases to off set the length of the chamber. I adjust the die of the shell holder .014" to get that magic .002" clearance.

And my cases do not have head space.

F. Guffey

[fguffey]

A brand spanking new Hornady headspace gauge was delivered to my door yesterday afternoon. It's easy enough to use, but you have to be careful to wiggle the case around until you get the smallest reading you can. Canting the case just a tiny bit in the caliper throws off your measurements by a couple thousandths.

The Hornady gage is not a head space gage, it is a comparator. Time and time and time again I have said the Sinclair/Hornday tool is not an accurate tool. It is not accurate because it has a radius on the datum. I make datums, my datums are not case friendly.

You could have purchased a digital head space gage; same thing, the tool is not a head space gage it is a comparator. Precision manufacturers of fine accurate tool identify the digital head space gage as a dial indicator stand. The only crowd that does not understand the difference are reloaders.

To determine the amount of error in your comparator you are required to use a standard. And then there is another way; learn to zero your the comparator.

F. Guffey

[JackEllis]

Originally Posted by fguffey

The Hornady gage is not a head space gage, it is a comparator. Time and time and time again I have said the Sinclair/Hornday tool is not an accurate tool. It is not accurate because it has a radius on the datum. I make datums, my datums are not case friendly.

You could have purchased a digital head space gage; same thing, the tool is not a head space gage it is a comparator. Precision manufacturers of fine accurate tool identify the digital head space gage as a dial indicator stand. The only crowd that does not understand the difference are reloaders.

To determine the amount of error in your comparator you are required to use a standard. And then there is another way; learn to zero your the comparator.

F. Guffey

I misspoke. I understand how the device functions, which is to compare the length of two cases from the base to a datum defined by the diameter of a point on the case shoulder. I'm not a machinist but I'm aware that all of the parts we're talking about can be imperfect, which is why the SAAMI diagram Randall posted includes allowable tolerances.

I'm not sure what you mean by a standard unless you're talking about a precisely machined part like a case gauge. I took a different approach, starting with a fired case that would not chamber in either rifle and then sizing it until the bolt just closed in the Howa (which has a slightly larger chamber) without requiring extra force. That sized case would not chamber in the Tikka but bumping the shoulder on that case by a small amount (less than .001) did the trick. That case is now my reference, or perhaps the "standard" you refer to.

Next time I set up the sizing die, I'll measure that case with the comparator, then set the die so that it moves the shoulder back by another .001

At the end of the day a) my cases need to be sized so the bolt will close, b) the cases need to be sized so they are not unsafe, c) if possible I would prefer to use the same brass for both of my .223 rifles even if it means I can't shoot one hole groups with either one.

[smoothy8500]

Somebody mentioned "headspace" and it triggered the Bat Signal....

[NorCalFocus]

Originally Posted by ar15barrels

Don't let Guffy hear you say that.
He's going to come and tell you about the 10 ways he can measure headspace without actually giving any useful information...

Damn it, you jinxed it Randall.

[fguffey]

Originally Posted by NorCalFocus

Damn it, you jinxed it.

The OP wanted to know about protruding primers on fired cases. As I have said many times there is something about the sequence of events between pulling the trigger and the bullet leaving the barrel loaders do not understand.

To prove the point I will ask a question about the firing pin driving the case forward. If the case is driven forward by the firing pin what happens to the neck length? And while trying to show off do not forget the 'WHY'.

F. Guffey

[JackEllis]

Originally Posted by fguffey

SO? Simeone should check to see if the inside diameter of the barrel is too large in diameter, or there is a problem with the powder or the bullet is too small in diameter etc.

F. Guffey

I read this again.

The gunsmith I visited asked about reduced loads. The bullets are Hornady FMJs, the powder is IMR4198, and Hornady's 10th edition calls for a max load of 20 grains. I loaded my rounds to 19.7. If there's a problem with the powder or the bullets it should show up in the Tikka and the Howa.

The Howa barrel may be larger but chrono data shows slightly higher MVs out of the Howa.

case locks to the chamber

Originally Posted by fguffey

case locks to the chamber

You're gonna have to explain this because the only way the case is "locked" in the chamber is if the shoulder is pressed against the chamber and the bolt face is pressed solidly against the case bottom. In that situation, the only case stretching that can occur between the shoulder and the base (or the case head) is radially (case gets fatter).

If the shoulder changes, it's because there's some space for the case to expand in the longitudinal (length) direction, in which case the shoulder should move away from the head (and towards the chamber). In other words, there needs to be some headspace for the shoulder to move.

As for the protruding primers, at some point I will load up a few rounds with properly sized cases ad the same bullet and powder charge (only one variable gets changed). If the primers don't stick out after they're fired, I'm satisfied.

[fguffey]

You're gonna have to explain this

When I fire my cases in my chambers the case expands and locks onto the chamber, as soon as pressure drops the pressure inside the case drops. The drop in pressure allows the case to released.

There are reloaders that grease their bullets and cases to prevent the case from locking to the chamber. In the beginning there was a reason for greasing the chamber. In about 1920 the military was using cuprio nickel bullets, the bullets were bad about streaking the barrel and building up clumps. Removing the clumps and streaks required another kind of chemical for cleaning the barrel.

F. Guffey

[focus]

Originally Posted by JackEllis

That case is now my reference, or perhaps the "standard" you refer to.

Next time I set up the sizing die, I'll measure that case with the comparator, then set the die so that it moves the shoulder back by another .001.

I think your system will work for you. But, keep in mind your brass standard will wear. You can monitor the wear by measuring the comparator body after zeroing the calipers with the brass standard. Just close the calipers down on the comparator body and the caliper will read a negative value. Write that measurement down. The post zero comparator body measurement will grow as the brass standard wears.

Cheers,

[focus]

Originally Posted by fguffey

I understand reloaders are infatuated with "HEAD SPACE"; Not me
F. Guffey

If we’re talking about wildcats; I agree with you. But, I cut commodity cartridge chambers to accept commercial ammo and I want my reloads to chamber in commercial rifles.

Cheers,

[ar15barrels]

Originally Posted by focus

I cut my chambers ~1.4 thousands over the go gauge length. I gauge the final cut DRO number that gives a snug bolt closure. The bolt won't close on the go gauge with a piece of scotch tape on the gauge head.

Cheers,

That's about perfect.
You will lose the 0.4 to cinch up at 60-80 ft-lbs, leaving you about 1.
I cut my chambers at 1 over go which generally leaves me around a half.
They won't close on a GO+1 gauge, but will close on a GO.

[ar15barrels]

Originally Posted by JackEllis

I read this again.

Don't engage him.
It only gets worse and worse.

[JackEllis]

Originally Posted by focus

I think your system will work for you. But, keep in mind your brass standard will wear. You can monitor the wear by measuring the comparator body after zeroing the calipers with the brass standard. Just close the calipers down on the comparator body and the caliper will read a negative value. Write that measurement down. The post zero comparator body measurement will grow as the brass standard wears.

Cheers,

Hadn't thought about wear and the problem is, I wouldn't notice it until primers started sticking out the back again. OTOH it's probably going to take a hundred uses or more for any wear to become apparent and by then I'll be...nah, that's too much information...

The calipers I'm using are mechanical so I wrote the gross reading down.

Originally Posted by ar15barrels

Don't engage him.
It only gets worse and worse.

Understood

[kcstott]

Originally Posted by JackEllis

The calipers I'm using are mechanical so I wrote the gross reading down.

Just because a set of digital calipers can display a .0005" don't mean it's reliable.

Calipers, All Calipers, Vernier, Dial, or Digital are at best only good to within .001" and I never trust them to be any closer than +/-.001"

if you want readings closer to .0005" you need a Micrometer. But the point of this was to inform you don't think digitals are any better than dials.

[JackEllis]

Originally Posted by kcstott

Just because a set of digital calipers can display a .0005" don't mean it's reliable.

Calipers, All Calipers, Vernier, Dial, or Digital are at best only good to within .001" and I never trust them to be any closer than +/-.001"

if you want readings closer to .0005" you need a Micrometer. But the point of this was to inform you don't think digitals are any better than dials.

Thanks. I only mentioned the digitals because they can apparently be zeroed in a way that allows differential measurements. A digital display has some usability advantages when it come to calipers but if I can still use a slide rule, I figure I can manage to read a dial. My wife keeps telling me mental exercise staves off Alzheimer's.

[LynnJr]

JackEllis
I will bite but only to show you that the Guffster only speaks in riddles. As Randall posted don't engage him as it wastes bandwidth.

Guffster
When the shoulder is bumped too much the firing pin pushes the cartridge away from the boltface. The powder ignites and using your words locks the case forward in the chamber. The head of the case moves rearward and reseats and flattens the primer plus it stretches the case nearest the web which results in casehead separations.
Nothing happens to the neck because when the brass was over bumped it lengthened the neck slightly then the neck was trimmed to 0.010 under chamber length. The neck shoulder junction is the stopping point for forward movement. The neck length shrinks on a properly sized piece of brass.
Maybe you could make up another nursery rhyme now.
I will call it the Frankie G rhyme.

[kcstott]

Originally Posted by JackEllis

Thanks. I only mentioned the digitals because they can apparently be zeroed in a way that allows differential measurements. A digital display has some usability advantages when it come to calipers but if I can still use a slide rule, I figure I can manage to read a dial. My wife keeps telling me mental exercise staves off Alzheimer's.

Agreed, I just see far to many people thinking digitals are more precise than dials. But yes for an incramental measurement they are easy to use