What are the numbers telling me..if anything

[cw308]

I have been reloading for 30+ years , then about 12 years ago I got into benchrest shooting , read a lot and found a lot of help on this forum when something puzzled me . I shoot a Rem.700 308 cal. My cases are also shorter after firing from expansion . I ordered a Go Gauge and with the use of shims I know my chamber length from datum to bolt face . I full length size only and I'm not loading hot , may take a few firings to get the cases to all size accurately , I size all my cases between .0015 - .002 no more or less . You can try stripping your bolt down , using only the bolt housti and chamber a fired case that will not chamber in your rifle and slowly full size that case down until it chambers without any resistance , size your cases to that measurement.may help in not oversizing your cases . Knowing your chamber length is the best way I feel . Hope I Helped in some way .

Chris

[F. Guffey]

. I shoot a Rem.700 308 cal. My cases are also shorter after firing from expansion .

that does not explain the problem the OP describes. You say your cases 'ALSO' shorten and that is all; it would help if you explained where the case shortened. The case can be measured from the mouth of the case to the case head, the case can also be measured from the datum/shoulder to the case head. This is another mind boggling thing but the case can shorten in length from the mouth of the case to the case head but get longer from the shoulder/datum to the case head. No one ever ask HOW? As the case expands to fill the chamber the neck is pulled back; no one ever notices the neck getting shorter and the case body getting longer.

Over 70 years ago the Wilson Case gage became available, those that mastered the use of the tool understood, those that never got around to mastering the tool declared the case had head space. And they described to tool as a 'drop-in gage'.

F. Guffey

[RC20]

those that mastered the use of the tool understood, those that never got around to mastering the tool declared the case had head space. And they described to tool as a 'drop-in gage'.

Alas, I am still struggling in the wilderness and I shall be there (well have been) for 40 years (long actually before (well I haven't) seen the light.

Lo though I walk through the dark valley of head space, I shall fear no cartridge for my groups comfort me (sometimes)

[cw308]

F.Guffey
Just answer to OP's question the best you can and stop picking out things others have posted . This will cut down on all the BS . I'm sure he'll be able to figure things out when sticking to the subject .

Chris

[Nathan]

Over 70 years ago the Wilson Case gage became available, those that mastered the use of the tool understood, those that never got around to mastering the tool declared the case had head space. And they described to tool as a 'drop-in gage'.

What are you talking about? Those cases accept sized cases only. The fired case condition you speak of cannot be evaluated with that tool.

Can you explain? Maybe it helps with the op’s question.....or maybe it dumps more bits in this mega thread!

Those of you out there whom argue case headspace vs chamber headspace vs cbtd.....c’mon it’s all English. Just talk to each other instead of playing my dictionary is bigger than your dictionary.

[F. Guffey]

What are you talking about? Those cases accept sized cases only. The fired case condition you speak of cannot be evaluated with that tool.

Nathan, I have suggested reloaders think before they make a fool of themselves, In your case there is an up side; there is a big chance I am the only reloaders that knows you have never read the instructions and most do not know what you are talking about.

The Wilson case gage is a loose fit for a full length sized case because the Wilson case gage is designed to measure cases before firing and again after firing. And? If a reloader had the ability to keep up with the measurements they would know if the neck increased in length and they would know if the case body from the shoulder of the case to the case head got longer.

The Wilson case gage has a two way datum, it measures from the shoulder to the mouth of the case and it measures from the datum to the case head.

And then there is the 'datum', the datum in the Wilson case gage has a radius, I understand no one has a clue what I am talking about when I mention the datum with a radius.

F. Guffey

[F. Guffey]

It is just something I do but I make chamber gages; most chamber gages are knock-offs of the Wilson case gage meaning they are cut to be used when the case head is flush with the end of the cage.

I make my chamber gages to match the chamber case head protrusion. Fir example the 98 Mauser with a case head protrusion of .110" outnumber Mauser 98s that do not have a case head protrusion of .110". And then there is clearance.

No one has ever seen a chamber gage with protrusion in use but when someone figures a way to make them there is a small chance reloaders will think they are one of the fastest way to measure the length of a case from the datum to the case head.

F. Guffey

[cw308]

What are the numbers telling me . Sorry Pal , I tried .

Chris

[hounddawg]

I was only half joking in my first post, you guys way over analyze. When the ammos accuracy hits a certain point the human factor kicks in and you never see a difference on paper no matter how perfect the ammo and gun is

[cw308]

dawg
My comment wasn't directed at you , I know when your pulling the chain . Hope things are going Well .

Chris

[Unclenick]

Griz,

Yes. Resizing a bottleneck case lengthens the head-to-shoulder dimension because the sides of the die make contact with the case before the die shoulder does. This squeezes the case narrower which also squeezes it longer. As the sizing stroke continues, the case shoulder arrives at the die shoulder and as you continues to press it up into the die it forces the top of the shoulder to start extruding up into the neck and forces the sides of the body immediately under the bottom of the shoulder to extrude up and become part of it. If this process does not go far enough, the case head-to-shoulder dimension remains too long.


Crapshooter2,

Check that when you have a case all the way up in the die you cannot see a crack of light between the mouth of the die and the top of the shell holder deck. If you can, turn the die in an eighth of a turn or whatever minimum amount it takes to just make that light crack go away at the top of the stroke.

Another experiment is to take two of those cases (223, I assume?) and resize one with the expander in the resizing die and one with it removed. See if they are the same length afterward. This is to determine if the expander is pulling the neck forward a little, giving you the long number.

[Nathan]

The Wilson case gage is a loose fit for a full length sized case because the Wilson case gage is designed to measure cases before firing and again after firing. And? If a reloader had the ability to keep up with the measurements they would know if the neck increased in length and they would know if the case body from the shoulder of the case to the case head got longer.

The Wilson case gage has a two way datum, it measures from the shoulder to the mouth of the case and it measures from the datum to the case head.

Thanks Guffey. Turns out the wilson ones are different!

[F. Guffey]

Thanks Guffey. Turns out the wilson ones are different!

Nathan, Forgive,

F. Guffey

[Unclenick]

Crapshoooter2,

This is just a P.S.

Continue to report dimensions as your instrument reports them rather than doing any rounding. A Ph.D. neuroscientist friend who does a lot of super-precision measuring of electrical currents in nerve cells once told me you never change raw data without an awfully good reason. It can make errors untraceable to do so. In this case, because of how internal rounding for that fourth decimal place half-digit works, you can't know whether the reading should be rounded down or up. So you reported the numbers correctly and should not change how you are doing that.

To my fellow handloaders who, like me, were born a little closer to the Jurassic period than the beginners: The modern digital calipers now frequently have a fourth decimal place in the readout, but it is only what is called a "half digit". That is, it only reads "0" or "5" and none of the between digits. In the fourth decimal place for inches it reads "0" until a quarter of a thousandth is reached, at which point it reads "5" and that remains until the reading reaches three quarters of a thousandth, at which point it returns to "0" and the digit in the third decimal place is incremented. So the electronics are already rounding up or down. The drawback to the half-digit system is you don't know which side of the half thousandth the reading is reflecting, so you can't know to round the half thousandth up, as you would if the readout was a full ten-count digit. As a result, your best bet is to report the half thousandth for a collection of readings and then rely on averaging multiple readings to settle out any error before rounding to three decimal places.

[Metal god]

It seems to me if you read the OP he pretty much knew what was happening . Also , I don’t understand why some in here are suggesting he must of had resistance when closing the bolt . The total variance of his measurements is only .0025 . As UN just pointed out that may have been only .002 and no more then .003 . If the OP had set the shoulder back .002+ . The OP would not likey feel resistance closing the bolt .

The answer is as he suggested in the OP . The case body expanded with out stretching back to the bolt face resulting in a shorter case . Seeing how the OP has not been back since what appears the thread going off the rails . He must have gotten what he needs from the thread early on in the thread .

Good luck crapshoooter2

[F. Guffey]

If the OP had set the shoulder back .002+ .

And then there is a remote chance he decided it is impossible to move the shoulder back with a die that has full length body support.

And it is even more remote that he decided he could not size a case for a chamber without knowing the length of the chamber from the shoulder to the bolt face.

And then it gets confusing when the case is fired with reduced loads.

F. Guffey

[Unclenick]

Yes. We still have no information on the actual load involved.

[Metal god]

Yes. We still have no information on the actual load involved.

Not sure we need it based on the result , if accurate . Not likely a max pressure load and even if the data said it was a light-ish load if the bullet was jammed into the lands then max pressure could be reach at moderate powder charges .

I thought it is well established a case can come out shorter both total case length and case head to datum then it went in ??? If so what's the big mystery here ? Did I miss something crapshoooter2 posted that indicates another issue needing to be worked out ?

[F. Guffey]

I thought it is well established a case can come out shorter both total case length and case head to datum then it went in ???

You missed that part where CW308 claimed he had fired cases that were ejected shorter. problem; he said nothing about shorter from where to where. And then you missed that part where I said it is possible for a case to shorten from the mouth of the case to the case head and from the shoulder to the case head at the same time.

I am the one that has fired thousands of rounds that got shorter but when that happens I always mention the case got longer from the datum to the case head and shorter from the datum to the case mouth.

I have also mentioned when forming cases I have cases shorten as much as .035", and then when fire forming I have had the same cases an additional .010". From all of that reloaders assume the case got shorter from the mouth of the case to the case head when. When a reloader is able to keep up they find the case gets longer from the datum/shoulder to the case head and shorter from the datum to the mouth of the case.

F. Guffey

[Nathan]

I thought it is well established a case can come out shorter both total case length and case head to datum then it went in ???

I have only seen that when it is a jam fit initially. When you talk pressures too light to move the shoulder forward, you are talked no 10000-15000 psi.....I’ve not seen that data!

[cw308]

F.Guffey
When I posted shorter from expansion . I use the RCBS Precision Mic my sized cases are 1.630 from bolt face to datum , my fired cases are 1.628 . I like from .0015 - .002 case space . It was easier when posting to just say my fired cases get shorter from expansion , just take my word for it the next time.

Chris

[Crapshoooter2]

Crapshoooter2: Yes I am still here and sometimes it pays to just read and digest. Also it is very interesting, informative and even entertaining to read the minutiae of the posts.
Unclenick: thanks for the information on the 4 decimal on a digital caliper. Now I can stop chasing the 0 or 5. Also on the die procedure, its function and how it affects the case., thru trial and error I picked that up.

If I may digress for a moment from the original Post and speak as to some of the frustrations of a newbie to reloading and some of the errors of a newbie. A lot of newbie buy a loading book, a set of die, watch a few YouTube videos, read a few Posts and jump into re-loading. What I and other like me don't understand is the relationship of how one thing affects other things and as one of the Post said " you have to under stand how to use the tools and what they do "

Lets take the resizing die ( all this is IMO and maybe wrong). The instructions that come with the die tend to be very simplistic. Insert the die , just touch the shell case holder, then turn a little more or something like that. Unless you have a locking ring or some way to make sure the die is in the exact same depth the next time you insert the die into the press you will get some possible variation in the shoulder length and case over all length if there is growth do to resizing. A newbie asked a question on the forum , if it was alright to trim before he resized his cases. IMO he does not understand the process.

Why is it important to a newbie understand the resizing die and its function. If I am correct, if you resize cases at different time and the die depth is different the shoulder length will be different. Now you got a bunch of resized case ( lets assume they are all the same trim length) but with slightly different shoulder length .When you get to the bullet seating die and you are trying to seat the bullet to an O.A.L. of . lets say, 2.240 , I wondered why no matter how careful I was in regards to press pressure, etc. , there was always some variation in O.A.L.. Could it be the slight difference of the shoulder? Since I suspect the shoulder determines how far the case goes into the seating die. What I am saying , if you are looking for accuracy you need to understand the tolerances you must meet and how the tools work to accomplish the objective. There is a pretty sharp learning curve for a newbie to have to climb and IMO there are no short cuts. I have, at the beginning, found myself having to go back and correct my procedure because I really didn't understand it correctly the first time.

The other frustration for newbies ( this is not a slam on anyone just an observation) On Forums, YouTube, etc., you have some folks who have great technical knowledge but are not great communicators, some are great communicators and have less technical knowledge and then there are those who has neither or hopefully both. If you are a newbie, it taken a lot of work to separate the wheat from the chaff. After looking at a number of forums, I jointed this forum because there is more wheat.

Maybe this might help when you reply to a newbie's post. Newbies KNOW NOTHING AND SUSPECT EVEN LESS.

I will close my rambling and Post another to update you on my original post of "What do the number mean?"

Thanks Crapshoooter2

[Metal god]

What was the charge and bullet weight used that resulted in those numbers ?

I will close my rambling and Post another to update you on my original post of "What do the number mean?"

I stand by what I've said They mean your case bloated shortening the length .

there was always some variation in O.A.L.. Could it be the slight difference of the shoulder?

No it's the difference in the bullet tips . The seating die seats from the case head pressing against the shell holder and not the shoulder in any way .

When you talk pressures too light to move the shoulder forward, you are talked no 10000-15000 psi.....I’ve not seen that data!

I'm assuming you are talking about making a wildcat cartridge where the extractor holds the case back not allowing the shoulder of the case to make contact with the shoulder of the chamber . This will allow the shoulder to blow out forward . However if you only have .003 or .004 of head clearance ( gap between the case head and bolt face ) after the firing pin has pushed the case fully forward stopping on the chamber shoulder . There is nowhere for the shoulder to blow/move forward so when the case expands and sticks to the chambers walls the only thing that can stretch or move is the head in the web area .

Now add a low pressure load and when I say low I don't mean 10k to 15k . I'm talking 45k to 50k-ish . Not sure the actual pressure but yes I'm talking 20k to 30k more then you're talking . How do I conclude this ? The fact I've loaded several 308 loads that fired just fine but my primers were pushed out of the primer pocket the same amount as my head clearance ( .003 to .004 ) . I concluded in those loads the charge/pressures were high enough to expand the case and stick it to the chamber walls but not high enough to stretch the case head back to the bolt face .

I'm going off of memory which is never good but one of those loads was 175gr or 178gr bullet and 37.5gr IMR 4895 at a velocity of about 2300fps 10k/psi or 15k/psi will not get you that kind of velocity . I'm not going to pretend I know what those pressures really were but they had to be 35k+

Anyways I'm not at home where my load data is . Later I'll post those loads I had . There are at least 3 different loads that primers pushed out of the primer pockets a little .

[USSR]

A lot of newbie buy a loading book, a set of die, watch a few YouTube videos, read a few Posts and jump into re-loading. What I and other like me don't understand is the relationship of how one thing affects other things and as one of the Post said " you have to under stand how to use the tools and what they do "

Crapshoooter2,

Now you know why I teach the NRA's Metallic Cartridge Reloading Course.

Don

[Crapshoooter2]

My original Post was posted because I had some once fired full resized cases with slightly different shoulder measurements 1.456, 1.455, 1.454 based on the use of the Hornady Comparator (not the ogive). The bullet used was a Sierra 52 gr #1410, 24.2 gr of Benchmark powder, the O.A.L. was set to the load data 2.240. Because I am still learning about reloading and was curious about the headspace of my rifle, I decided to load the 3 each of the 3 different shoulder measured case and fire them. All of the cases went into the rifle easily and no difference in closing the bolt was felt. Shot all the rounds, all were ejected easily. I then measured the cases as I did before with the Hornady comparator.

I had read about FIRE FORMING a case, the case would expand and conform to the chamber/headspace There I was expecting the cases to expand and I expected the length of the shoulder measurement ( by the H.C.) to have increased some. When I measured the cases, I was surprised the cases 1.456,1.455 measured 1.454 and the 1.454 was still 1.454.

As pointed out by Unclenick the cases can expand in more that one direction and there were other factors to consider.

But it was still an out come that I was not expecting and still was bothered by. After reading all the posts, I decided to try something different. I wanted to eliminate any reloading error that I might have caused that affected the original results. This time I would use manufactured rounds.

I took 3 Hornady 55 gr V-Max rounds, 3 Hornady 55gr SP and 3 TZZ 233 REM ( case head stamp) 55 gr round. Measured the shoulder distance using the Hornaday comparator. All measured 1.452 ( I wondered why all measure 1.452 ). Measured the O.A.L for interest. They all chambered with ease and the bolt closed with ease. Fired the rounds. Then measured the cases as I did before.

Now another surprise. All the Hornady cases still measured 1.452 but the TZZ 233 REM measure 1.454.... out of all the rounds fired in the two tests,they were the only ones to expand in the direction that I was expecting.


I have no idea why the TZZ did and others did, what they did. So I did it again and got the same results.

So my solution was to go to my den, have a couple of cocktails and call it a day.

What I thought was a simple test turned out to be a conundrum to me.


Thanks for your ideas and suggestions

Crapshoooters

bolt action Predator Stiller, Kierger match grade barrel 1;12 twist, Jewell trigge,r use for Prairie Dogs. Every accurate