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Old June 14, 2011, 09:00 PM   #26
Brian Pfleuger
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Here's an interesting tidbit... I just dug out some Hornady .204 brass that has been fired only with the original full-power factory load. Of 15 cases, 12 measure +.003 on the "nominal" length while 3 measure +.002

This creates a great cluster of cases in the +.003/4/5 area, about 23 out of 39 measure in that range. The only other area with more than 2 is the chosen "nominal" measurement.
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Old June 15, 2011, 07:10 AM   #27
mrbro
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PZ, will the cases that measure very long still chamber?
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Old June 15, 2011, 08:41 AM   #28
F. Guffey
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Again, I measure the chamber first, then form, then fire, (this stuff called head space stuff), there is me, then there are the HARD HEADED, they remind me of constituents, people with two standards, me? I have one standard.

Again I measure the length of the chamber first, I adjust the die in the press to the shell holder, constitutions fire then measure.

I measure the effect the chamber will have on the case when fired, others measure the case after firing,

And I use the versatile full length sizer die, no need to order Redding Competition shell holders for $50.00, it is not necessary to grind the shell holder, there is no reason to grind the bottom of the die unless you are hard headed, the feeler gage will allow a reloader to size cases from (short chamber) .012 thousands shorter than a minimum length case to infinity, back to "this stuff called head space", I want/must know what rifle is being used, seems the person asking the question wants that to be the last bit of information I need to know. And again, Hatcher moved the shoulder forward .080 thousands and became a case forming wildcatter, and I fired cases in a chamber with .127 thousands head space "called stuff" and got fired cases with short necks, again there are those that think the case, powder, bullet and primer can outrun the firing pin and is able to escape the firing pin impact until the shoulder hits the shoulder of the chamber AND I ask, if any of that is true why did the necks of my cases shorten.

Head space???? I check the length of my chambers, I adjust my dies to the shell holder, and I make tools to measure the length of the case from the head of the case to it's shoulder, and this stuff called head space is no mystery to me, when the bolt closes the chamber gets dark and for most the light goes out, Me? I measure head space as many as 3 different ways with out a head space gage, BECAUSE, the head space does not tell me what effect the chamber has on the case when fired, the head space gage will indicate the bolts ability to close, I want to know 'BY HOW MUCH' I want to know the effect the chamber will have on the case when fired, measuring the case after firing verifies, as those that make this stuff up before me say, the Mauser when fired is not rigid? Then they say to be accurate the receiver must be rigid etc., etc..

When putting all the effort into measuring cases after firing a lot of time is wasted when expectations are too high.

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Old June 15, 2011, 09:37 AM   #29
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Exactly what Guff said: just use a set of go-no go gages. Again, a tolerance is already built in place.

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Old June 16, 2011, 01:05 AM   #30
Edward Horton
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You need a reference point to start and below I use a GO gauge and this is "zero".



New unfired .243 cases were minus -.002 to -.009 (shorter than minimum headspace or GO)
A fired case was plus + .002 (longer than minimum headspace or GO)

Your fire forming is very important because a new cases above can have .011 head gap clearance or air space between the bolt face and the rear of the case. The head gap clearance can cause the case to stretch in the web area as seen below. Seating your bullets long and jambing the bullet hard into the rifling will hold the base of the case against the bolt face, and prevent stretching.



Once fire formed the case is the same length as the chamber and can be neck sized only until they become hard to chamber. At that time you would bump the shoulder back .001 to .002 with a full length sizing die

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Old June 16, 2011, 09:31 PM   #31
Brian Pfleuger
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Quote:
Originally Posted by mrbro
PZ, will the cases that measure very long still chamber?
Yes, but not with normal ease. They're quite difficult in the Encore, not much the Ruger... Lots of torque with that bolt.

I've decided to bump the shoulders back .001 from the longest length and leave it at that... The shortest cases will eventually catch up and everyone will be equal.

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Old June 17, 2011, 09:14 AM   #32
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Are they hard going back in as-fired? If so, in the strictest sense, and regardless of how the brass looks, that would be a pressure sign in that it means steel is moving outside its normal closed action volume. It might only be due to a loose or bent pin or bolt lugs in need of lapping, rather than pressure being high enough to be dangerous. But, it's still a pressure-dependent variable, so it might help explain at least a portion of the differences in fired case lengths you are getting.
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Old June 17, 2011, 10:22 AM   #33
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In reference to the Encore, there were a few of them that were definitely fired over-pressure. Besides that, that had been fired without resizing at least once before.

With the 204, those cases have been fired 3-5 times without resizing. Would that explain the fit or would it still be a pressure issue? I full resized them without moving the shoulder and they were still tight. After bumping the shoulder they were fine.
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Old June 17, 2011, 10:41 AM   #34
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Perhaps I'm misunderstanding your use here so bear with me a bit. This is based on using mine together with the bullet & chamber comparator.

I thought the way to set up the gauge & calipers was to attach the adapter to the jaw that moves, using the offset cut either centered for measuring cartridge OAL ( so the tip of the bullet can be measured on the knife edge of the fixed jaw) or offset for measuring the case from base to datum line where the case base is measured off center to reduce primer issues (more later on that). Then the caliper is closed to lightly grip the adapter, the locking knob tightened & the caliper set to zero. This is supposed to eliminate play in the fit of the adapter to the caliper blade, & between the adapter & the caliber specific gauge by applying a little compression when tightening the set screw for the caliber specific gauge & the thumb nut for the adapter.

To use after this you were supposed to measure the round, take a note of the reading which would be fired case length from base to datum line & use that for calculations.

I'm just wondering if trying to use the caliper as a zero measure for the "standard" case to allow a +/- tolerance or deviation, instead of zero with the adapter is causing an issue?

One other thing I discovered that made a difference was the fired primer!!!! Sometimes there will be distortions to the cup in firing that cause false reads, you might want to decap a short, long & "normal" case & remeasure, just to eliminate that as a possible error source.

Sorry if I misunderstood your zero setting, it was a bit unclear to this foggy ol brain.
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Old June 17, 2011, 11:20 AM   #35
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Wogspotter,

I am set up as you describe except that I have deprimed all cases so I am using the gauge centered all the time. All else is exactly as you describe, per instructions from the set.

I initially zero the calipers with the gauge installed and then began measuring. Once I had a collection at the "middle" length, I zeroed the calipers at that length and use it as "nominal" just for the sake of a standard.

There is no (unrepeatable) measuring error. I can zero the calipers at the shortest length and all cases measure the same difference. I can zero it at the longest length and they still all measure the same difference.
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Old June 17, 2011, 01:02 PM   #36
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When you start an FL resize cycke, as soon as the sides of the die touch the sides of the case, they start squeezing it out longer than it started. Encountering the shoulder in the die then pushes it back again. The wild card is usually the expander. It can sometimes pull a shoulder forward again if there isn't enough inside neck lubrication (or sometimes even if there is). If you haven't tried it yet, remove the expander from your FL die and see what you get after the resizing. The necks will be too narrow, but you can widen them by putting the expander back in, lubing the necks inside, then running them up over the expander. Then see what you have afterward and how it compares.
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Old June 17, 2011, 01:46 PM   #37
Brian Pfleuger
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Nick, I'm using a Lee collet die for the necks.

The .204 cases typically barely touch the body die. Only the last 1/2" or so is sized. The 7mm cases get resized probably about 3/4 of the case length, judging by the marks.

Last edited by Brian Pfleuger; June 17, 2011 at 01:52 PM.
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Old June 17, 2011, 02:07 PM   #38
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Have you tried annealing the brass?
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Old June 17, 2011, 07:23 PM   #39
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No, not yet. It is fairly new though. Virtually none of it has been fired more than 3 times.
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Old June 17, 2011, 09:59 PM   #40
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OK. I was reading the FL resize as distinct from the bump back, but it's actually the same body die.

It is normal with repeated neck sizing that the cases gradually get too tight to chamber and have to be sized down. How many rounds that takes depends on the pressure you are firing them at, so that could indeed be all that's happened there.

Once the cases are getting tight like that, how to they compare on the case headspace gauge? I would expect them to be pretty similar; all heading toward the same limit.
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Old June 17, 2011, 10:39 PM   #41
F. Guffey
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Bad habits, chamber a round and then fire it, then neck size if five times and then full length size the 6 time fired case to start over, when I start over I start with a new case, when I size I know the length of the chamber first, I then adjust the die with a feeler gage to prevent moving the shoulder further than necessary, that technique is not possible because reloaders do not know the length of the chamber then they put too much confidence in their ability to measure a case after it has been fired, again I measure the chamber first, and I think the neck die is cute, I own several, neck sizer dies are nice to have when forming cases for chamber I do not have dies for.

And I do all that work without a head space gage, but if I had a head space gage I would know what to do with it, I would use the go-gage by converting it to a go-to infinity gage (in thousands) and if I had a field reject gage I would use it to check head space from minimum length to go-gage, to no-go gage, to field reject and beyond.

And again, there is the demonstration, the case, powder, bullet and primer outruns the firing pin and escapes the firing pin by accelerating to a speed = to the speed of the firing pin, HOW DOES IT DO THAT? And it all happens before the primer is crushed, my firing pins crush the primer before before the case, bullet and powder knows their little buddy got crushed.

And the case is not grown to full size until it has been fired 5 times?

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Old June 17, 2011, 10:49 PM   #42
Brian Pfleuger
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Quote:
Originally Posted by Unclenick
Once the cases are getting tight like that, how to they compare on the case headspace gauge? I would expect them to be pretty similar; all heading toward the same limit.
The only ones that chamber tight are at the upper limits.

The big surprise is that fireforming the cases with TrailBoss didn't seem to produce much consistency. Maybe I need to use a higher charge next time. Some of the cases seem to have expanded .004-.005 while others appear to be unchanged from factory condition.
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Old June 18, 2011, 08:06 AM   #43
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Ed Horton - I always thought headspace was a measure from a datum on the case shoulder. I love the graphic. It copied and pasted into a power point document and the animation works. Thanks for sharing.
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Old June 18, 2011, 08:10 AM   #44
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That would be true with a rimless case, (such as the 7mm 08) which is a necked down .308 case. If you look at the illustration it relates to a rimmed case where headspace is exclusively on the rim.
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Old June 18, 2011, 08:18 AM   #45
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Sounds like you need a new graphic depicting the rimless case.
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Old June 18, 2011, 09:17 AM   #46
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Excess headspace is the wiggle room from head against the breech face to as far forward as the cartridge case it can go in the chamber, whatever is stopping it. Rim for the rimmed round, shoulder for rimless bottleneck, case mouth for rimless straight wall, belt for belted magnum case, or extractor hook for when the others fail to stop forward movement in time. I like seating bullets out to headspace the bullet against the throat of the bore in the 1911.


Peetza,

When you get no shoulder change with TB, then gas has bled out around the case mouth before pressurizing the case enough to stretch. Increasing charge should help. Seating the bullets out to jam into the lands to raise the start pressure should help.
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Old June 20, 2011, 03:35 PM   #47
F. Guffey
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For me? There is no wiggle room, I accept what I have, I measure first, size and or form the case to off set the effect the chamber will have on the case when fired. Others fire first, become fire formers? Size cases 6 times and then start over, and still I ask "How do they do that, start over??


November 22, 2010, 02:16 PM
"seating the bullet into/against the lands "....seated out so it engages the rifling and holds the case head firmly against the bolt face...." this does not happen because of advise already given. First there is the primer that accelerates to a sped equal to or greater than the speed of the firing pin strike, I use fire forming primers, my primers are crushed by the firing pin before the primer knows it was struck, that leaves the case, powder and bullet setting still until my primer ignites (time is a factor), when the primer fires up it drives the case forward and igniting the powder (time is a factor), when the powder ignites pressure expands the case against the chamber, but because time is a factor the bullet is in the barrel before pressure is at it's max. Then there is that part where the case locks onto the chamber, if the case is driven forward by the primer the case i8s head is not against the bolt face.

Then there is the measure before and after, necking up a 30/06 to 338 pr 35 will shorten the neck, if necking up the case requires effort, the case could shorten or compress between the head of the case and shoulder when fired the case could shorten even more, when the case body fills the chamber the neck of the case is pulled back to form the neck, sharp shoulder and larger case body, SO, you can expect the fire formed case to shorten as much as .040 thousands, my opinion, the 30 Gibbs neck is short enough at .217 without causing it to get shorter. As an alternate method, I use 280 Remington cases , the 280 Remington is 2.540 long with a shoulder .051 thousands ahead of the 30/06, I neck the 280 up to 338/06 then size the neck up case by forming the second shoulder, in doing so I determine the head space of the 30 Gibbs chamber.

Problem: I chamber the 30/06 to 30 Gibbs, this leaves the length of the chamber unchanged, 2.495 + a little, the 30 Gibbs chamber length is 2.460 + a little, and that is the reason I use 280 Remington cases, by the time I neck up the case, establish a second shoulder and before fire forming I have added .040 thousands to the length of the neck, not as long as a 300 Win Mag neck but if most consider the 300 Win mag neck short they should consider the 30 Gibbs neck too short.

I do not use cereal, wax and or t-paper, I form cases once, the last Gibbs I formed I use the maximum powder load for a 150 grain bullet, instead of a 150 grain bullet I used a 200 grain bullet(do not try this at home), as I said 'time is a factor' and I used the one 30 Gibbs barrel to road test three Mauser receivers, the max load of 4895 for 150 grain bullets worked for fire forming with a 200 grain bullet when fire forming, after the case was formed that load could be the maximum after the case is formed (because time is a factor).

http://www.z-hat.com/Cylinder.htm

The cylinder brass by R-P is 2.650 long, for those that know when to quit forming when the case fits the chamber cylinder brass is the best option, again, this brass came out too late for me, I will never need another piece of brass, for wildcats and case forming the R-P cylinder brass is a bargain at $37.00 for 20.

F. Guffey"

And my favorite case is the 280 Remington or cases fired in a trashy old chamber. Cases for the few that know what they are doing are not available, cases for reloading are only availabe for those that load, fire and then try determine what effect the chamber had on the case when fired.

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Old June 20, 2011, 09:11 PM   #48
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I misspoke. The wiggle room is excess headspace. I have fixed that. It occurs with new cases, as they normally fit a chamber. That's what most folks start with. If you have some kind of parent to form down, then, of course, you have the option to start without excess headspace.

The bullet touching the lands, as I suggested, was to raise start pressure. No expectation it would prevent the primer driving the case forward to meet the headspace determinate. Just trying to get enough pressure before the bullet leaves the case so it seals the chamber against gas getting around the neck and shoulder. I'm presuming that's what has happened in the examples where his fireforming failed.
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