Increasing Headspace-slow loads

[joeb33050]

It is often said that shooting cast bullets slow in not-rimmed-or-belted cases increases headspace.
I've seen this, or thought I had until today. I remember cases with the primers sticking out in a lead gun/some lead guns, but that was long ago and now I'm doubting my memory.
One explanation is that the firing pin strike drives the case forward, moving the case back and increasing headspace.
Today, 11/16/06, I did this test for the third time on the third gun.
Win M70 Target 30/06. I "killed" 26 primers with marvel mystery oil.(I did this test at home, in the condo.)
Put an empty case in the gun.
Removed the firing pin from the bolt.
The bolt closed easily on the case.
Made a .004" copier paper patch to fit the bolt face, put it on the bolt face, the bolt would not close with a little pressure.
After testing and fiddling and firing 26 primers in that one case, the bolt closed easily on the fired case-wouldn't close with a little pressure with the paper patch on the bolt face.
Now others have increased headspace with the firing pin striking the primer, but I can't and this is the third time I've done this test.
IS THERE SOMETHING WRONG WITH MY TEST?
Another explanation is that the primer acts as a piston in the primer pocket cylinder, the primer pressure acting on the primer pocket-less the flash hole. If true, firing 25 or so primed-only cases should move the shoulder forward and increase headspace.
???
Does anybody know?
Thanks;
joe b.

[mike in co]

i think we got a terminology error going on here....

headspace is a mechanical measurement of the CHAMBER on a rifle.
( there are diff headspace types but for most of us and in the case of the 30'06 it is from a specified dia in the shoulder back to a datum line that represents where the base of the case should be in an ideal chamber)

how much a case grows or does not grow is not headspace.

how much you size your case is not headspace.

headspace growth would be the bolt face being machined off, the lugs in the bolt being worn, polished or deformed , the lugs in the reciever being worn, polished, or deformed, and lastly streching the bbl in the chamber...ouch.

the size of the case is not headspace, it is the case and how you sized it....you size it in your dies and you could say you size it when you fire it, tho most of us just call it a fired case.

[mike in co]

i dont see 25 firings as unusual for a bolt gun.
i saw a test where a single 308 case was fired 50 times ........just neck sizing.

brass stretches as fired, but then pulls back a little. this is why neck sizzing for a single rifle works so well in improving accuracy...the brass fits the chamber.

i have seen some loads where primers backed out a bit, but have never seen an accurate load that did that...maybe just my luck.

with lite loads used with lots of cast boolits, case streching , in my case, has been very minimal.

[felix]

Mike, you are correct indeed. But, we can't talk about that because we are assuming the gun does not change between loads. Therefore, the headspace has to be defined herein as that length of case such that the "bolt" closes "tightly" without deforming the case. Like on a revolter, the case rim seldom is thick enough to lock in the case as it should. You already know that. So, either we say the case is short (rim), or the chamber (end shake) is long. ... felix

P.S. It is freebore, free of bore, or freegroove? Same type of bad language. ... felix

[Scrounger]

Maybe I'm missing some important point but I don't think there is any relevance between 'firing' a primer loaded only case and an actual loaded round, even a lightly loaded cast bullet round.

With the primer only, I can understand the case being driven forward a bit and creating a small but not significant amount of headspace.

With the loaded round, what is enough to force the base of the case back against the bolt and cause the shoulder to blow forward and match the case's headspace to the chamber's headspace? Forty thousand PSI would surely do that but would 10 or 12 thousand do it, or would it allow the primer (and shoulder) setback? The actual breakpoint between setback/no setback would depend not only on chamber pressure but also the softness of that particular piece of brass.

Or did I miss something?

[Pepe Ray]

Felix and Mike , SHAME on you both. :shock:

Pepe Ray

[felix]

OK, Pepe, lets call it freebore, freecase. Shame, shame is par for the course. Nat Hawthorn would have a field day with such a scenario. It did take him a whole page or two to describe a facade (of a wall) in the first chapter of his Scarlet Letter, right? ... felix

[mike in co]

i am pretty anal about terminology......

you want to talk about how much sizing is required to get your brass to fit your rifle, or how much your brass grows when fired in your rifle, fine, but it aint headspace. its the size of your brass in relationship to the size of your chamber. headspace is a gunmith term used when chambering/fitting a bbl to a rifle or a measurement to look at the wear on a used rifle.

you cannot change the headspace in your rifle by sizing brass. most of us cannot change the headspace on the rifle (ok full cases of bullseye may change your headspace!).

sorry felix, i dont see the need to redfine the term. call it what it is, dont change the world. there are multiple spots on a case that can cause the bolt to close with a slight push or lite fall , your choice. a large case base , a long neck, or shoulder length all would control how the bolt closes, but only one of those is related to headspace. so lets call a sized case a sized case, and a fired case a fired case. you can relate its shoulder length in relation to your rifle.....but it aint headspace, it is just the lenght of your case.
as an example: i SIZE my ar10 308 win fired brass aprox .001" less than the chamber, and i SIZE my ar15 6ppc fired brass aprox .0005" less than the chamber.


the problem here is that anyone LEARNING from this discussion , will move forward with the WRONG definition of headspace. any future discussions these people have will be wrong, and it just goes down hill from there.

[felix]

Why size the case at all? The neck, if not enough springback, OK. ... felix

[felix]

Mike, gun definitions suck all over the place! It has taken me quite some time to pick up on some of these issues because of me not knowing what the author was talking about. A picture is worth a thousand words. I tend to listen to what the person is asking and try and picture that. I try to answer in his terms, not mine, and I am sure you attempt the same by your answers when requested. ... felix

[Pepe Ray]

Mike in Colo.
I understand about anal. Been there a time or two myself.
Now , would you please tell JoeB what term/word to use so he could ask his question to satisfy you. I'm pretty shur that you know what he was trying to ask.

Felix , I dont read "dirty" books.[smilie=1:
Pepe Ray

[Bass Ackward]

If you seat into the lands with cast, then it doesn't matter how heavy or light your loads are. Primer blow or back track has no negative effect because it is held solid against the bolt face. And brass will expand from the proper locations / area as opposed to the critical WEB area.

All of my brass used for cast has .... tighter headspace fit than new brass for this reason.

[D.Mack]

joeb33050...... Not sure exactly what you are asking, but I don't think your memory is failing. Yes the firing pin can drive the case forward, ( or maybe it was just forward when the firing pin hit it)so when firing, the the firing pin holds the case for an instant, then the pressure holds the case to the walls, the primer backs out a few thousandths, then the case grows to fit the chamber. this can result in a primer that sticks a revolver (very low pressure, primer still protruding) or primer backs out just a little, then the brass comes back, so in forcing it to reseat, it flattens to the point it looks like excessive pressure( all the recoil energy is on the face of the primer only, for just an instant). All of this just means the case was smaller than the chamber in all respects. In some cases it will cause streching of the web, and eventual case separation, Blame oversizing or too large a chamber, but head spacing is whatever is supposed to cause the cartridge to come to a positive stop when inserted into the chamber. DM

[NVcurmudgeon]

Let me tell you what I found by emperical means. (Please notice that the word "headspace" will not pass my typing fingers again during the rest of this post.) I have a rebarreled Ruger 77 in .35 Whelen. There is never a bit of case fit trouble when firing full power loads. I use full power cases until I am bored with them. Using my standard CB load of 20.0 X 2400 and a 213 gr. (actual weight) NEI 220358 boolit at a mv of 1700 fps, and PARTIAL FULL-LENGTH SIZING, I begin having misfires around the tenth firing. This occurs with either Rem. .35 Whelen cases or cases formed from Rem. .270s. The Wilson case gauge then shows a reduction in head to datum line measurement. I next bought a Redding (real) neck sizing die. So far the group of cases that I am watching are still sure-fire after 17 firings. My wild guess is that the partial full-length sized, low pressure loaded, cases are not obturating as well as desired, and that the P.F.L.S. is exacerbating the situation by very gradually setting back the shoulder.

Strange things happen when we tinker with cast boolit loads at low pressures, but who cares? I guess I could expand the necks to .375 to create a secondary shoulder when they start misfiring, but it's a lot easier to toss the cases and move on.

[mike in co]

no, i can't. i'm not sure what he is trying accomplish.
brass shrinking ?? case lenght streching or shortening ???

not sure of what he is trying to prove or disprove.....


so maybe he will tell us what he is actually looking for.

i see no reason to expect a case to change its shape/length just due to dropping a firing pin on a dead primer.
i would be surprised to see any significant change in a case from firing a primer only( no powder, no boolit, no wad).

do primers occasionally back out...yes.

[dbldblu]

I think you need a live primer to make this happen. The force of the primer blows the case forward and then a low pressure load will not blow the case back to reseat the primer. I have had this happen with light cast bullet loads. Some people report that they enlarge their flash holes to avoid/lessen this phenomenon. Such cases are then unsuitable for full power ammunition.

In his book, P.O. Ackley advised lightly lubricating cases and using starting loads to fit cases to a rifle with headspace. I tried this with some of my cast bullet cases that were exhibiting primers backed out by .013" and it worked like a charm.

Please note that cases should not be lubricated on full power ammunition.

[Phil]

Er, you guys might want to read through your old American Rifleman magazines from the fifties or early sixties. Maybe the NRA reloading guides. Not too sure where it is but they ran all these tests years ago. Not one theory or another but what actually happened when you fired a light load in a RIMLESS case. Head to datum length of the case increases significantly. Never tried it myself as all the data was in what they printed, complete with pictures. No need to beat a dead horse.

I think I know what headspace is. I've probably fit and chambered as many or more barrels than most.

Cheers,

Phil

[Scrounger]

I think you need a live primer to make this happen. The force of the primer blows the case forward and then a low pressure load will not blow the case back to reseat the primer. I have had this happen with light cast bullet loads. Some people report that they enlarge their flash holes to avoid/lessen this phenomenon. Such cases are then unsuitable for full power ammunition.

In his book, P.O. Ackley advised lightly lubricating cases and using starting loads to fit cases to a rifle with headspace. I tried this with some of my cast bullet cases that were exhibiting primers backed out by .013" and it worked like a charm.
Please note that cases should not be lubricated on full power ammunition.

Another way to do this is to seat the bullet out enough that it jams in the lands and holds the case back against the bolt face; firing blows the shoulder forward to its correct location.

[Phil]

Hi Scrounger,

It won't always work that way. I built a really radical 280 Improved one time for a long range match cartridge. Jamming the bullet into the rifling only resulted in case separations. Oiling the cases didn't work. Only when I hydraulically formed the cases for good shoulder crush and then fired the cases with heavy loads did I get really good results. I had first necked the cases up to 30 caliber but evidently that wasn't enough. Perhaps I should have gone to 8mm or 338 but I made a hydraulic die just to see how it would work.

Another time, a fellow shooting on the bench next to mine was trying to form some K Hornet brass from regular Hornet brass. He was losing brass due to separations about every other shot. I told him to lightly oil the cases, which he did. He never lost another case. What happens when the brass is dry is that the thinner neck section obturates quickly and at lower pressure. It really hangs onto the chamber and as pressure builds and the body of the case expands to fill the chamber the case stretches and exceeds its elastic limit. It is held solidly at the neck so the neck area can't move so the case separates. There is a different mechanism working with a rimmed case, as opposed to a rimless case.

Interesting discussion,

Phil

[swheeler]

Joe B; I see nothing wrong with your terminology of headspace, there is "cartridge headspace" and "chamber headspace" both are set by SAAMI. In doing so they insure that all ammunition that is within spec(cartridge headspace) will chamber in all rifles that are within spec - even a minimum headspace chamber, open a Sinclair International catalog- you will see for sale CARTRIDGE HEADSPACE GAUGES, so to the handloader headspace represents the linear endplay of the cartridge in the chamber with the bolt closed.
Therefore a rifle with excessive headspace(chamber headspace) can have that excessive headspace removed by increasing cartridge head to datum line length, fireform the brass and don't full length resize- read leave the shoulder forward.

[mike in co]

Joe B; I see nothing wrong with your terminology of headspace, there is "cartridge headspace" and "chamber headspace" both are set by SAAMI. In doing so they insure that all ammunition that is within spec(cartridge headspace) will chamber in all rifles that are within spec - even a minimum headspace chamber, open a Sinclair International catalog- you will see for sale CARTRIDGE HEADSPACE GAUGES, so to the handloader headspace represents the linear endplay of the cartridge in the chamber with the bolt closed.
Therefore a rifle with excessive headspace(chamber headspace) can have that excessive headspace removed by increasing cartridge head to datum line length, fireform the brass and don't full length resize- read leave the shoulder forward.

too simplistic of an answer. saami does have specs for chambers and for cartridges. there is a design gap between the two to ensure that guns and ammo built to saami specs are compatable.
for the record( go look at a saami drawing)....HEADSPACE IS ONLY LISTED ON THE CHAMBER DRAWING !

in .30'06 min headspace is 2.0487, max case at the .375 shoulder datum is 2.0526
...saami believes a .0039" case crush is ok.

opinions are ok...but there are some things that are black and white...like it or not...and headspace is one of them.

[swheeler]

Do Da , Do Da, blah, blah, blah
"The "datum line" is a position on the shoulder defined by the military or SAAMI drawing as appropriate. One measures this dimension by means of a chamber headspace gauge. These can be graduated in explicit headspace dimensions (as are Match Gauges for the .308 Winchester) or in qualitative terms: Go, No-Go, and Field. (Chamber headspace gauges are available, of course, from Fulton Armory; see the Parts and Accessories Page for your rifle of interest!) The amount of clearance allowed for a nominally dimensioned cartridge can be inferred by this measurement of headspace. Of course, the actual headspace obtained (i.e., the clearance between the base of a chambered cartridge and the bolt face) depends on the "headspace" dimension of the cartridge, which can be measured by a *cartridge* headspace gauge. "- Fulton Armory

[trk]

As long as we're defining terms, on a lighter note:

With bullets, the headspace is the GAP between two surfaces - typically between bolt face and the rim (if rimmed ctg); but I use the the term in manufacturing "operator headspace" to mean the gap between the ears.

[joeb33050]

i think we got a terminology error going on here....

headspace is a mechanical measurement of the CHAMBER on a rifle.
( there are diff headspace types but for most of us and in the case of the 30'06 it is from a specified dia in the shoulder back to a datum line that represents where the base of the case should be in an ideal chamber)


In the next edition of the book there's a chapter 6.2.7 on headspace. I wrote a definition of the word based on commonly used and understood meanings of the word. Here's the definition:
"Headspace" is a word with a number of slightly different meanings all centering about the fit of a cartridge in a gun. There's the "mechanical drawing" definition of headspace, the difference between that definition dimension and the cartridge dimension (the tolerance, that allows us to chamber a cartridge), and "headspace" as the term for excess headspace that may cause trouble.

If you'd like to add to the chapter or revise it or edit it, I'd be happy for your input.
Our language changes all the time, both the written and the spoken language. Many-me too-resent this a little.
Also, there are some technically correct terms within a discipline that are not used "correctly" by the majority.
Physicists could properly describe all 2 or 3 pedals on the floor of an auto, and the round wheel we hang onto, as "accelerators", but they're kind enough not to.
Economists define "investment" as an addition to the capital stock, so when one buys shares of Amazon, one isn't investing-but is trading paper for paper.

I'm always looking to be corrected, anxious for it. Not this time, I don't think.
joe b.

[Char-Gar]

Joe...I also understood your post and see no problem with the terms. I have always understood the difference between chamber headspace and a condition of excess headspace cased by cases having the shoulder shoved back.

A chamber can be long, showing excess headspace via the gauges, but when cases are fitted to the chamber, there is no excess headspace with those cases.

Headspace is a dance between the chamber and he case.

My understanding of your orginal, post is the shortening of the cases occurs with very light gallery type loads. I also understand the primer is the culprit and not the blow from the firing pin.

I am currently playing with a lot of LC68 Match cases which have had the flash holes opened up with a #28 drill. I probably won't use loads low enough for the primers to cause case shorting, but these cases seem to work just fine with the load level we usualy associate with cast bullets loads. In my case 1.6 to 1.9 K fps in the 30-06.

The cases were first fired in the rifle with service level condom loads.

My goal is to have a lot of cases dedicated to one rifle for cast bullet shooting that can be used for any level of cast bullet shooting. The cases will be an exact fit to the chamber, need only neck sizing and be "everlasting".

I have never experienced this case shortening, but it is well documented enough to know it exists and is not a myth.

[joeb33050]

I have a rebarreled Ruger 77 in .35 Whelen. Using my standard CB load of 20.0 X 2400 and a 213 gr. (actual weight) NEI 220358 boolit at a mv of 1700 fps, and PARTIAL FULL-LENGTH SIZING, I begin having misfires around the tenth firing. This occurs with either Rem. .35 Whelen cases or cases formed from Rem. .270s. The Wilson case gauge then shows a reduction in head to datum line measurement. I next bought a Redding (real) neck sizing die. So far the group of cases that I am watching are still sure-fire after 17 firings. My wild guess is that the partial full-length sized, low pressure loaded, cases are not obturating as well as desired, and that the P.F.L.S. is exacerbating the situation by very gradually setting back the shoulder.

This strikes a chord. You're suggesting that PFLS moves the shoulder back=increases HS. I imagine a rough neck-sizing area on the FLS die and maybe a dirty neck and the die grabs the neck and pushes the neck and shoulder DOWN, increasing headspace a little. Shoot it with a heavy load, the case expands. A light load leaves a little HS, the next sizing adds a little....
I can't get the firing pin to drive the case forward enough to increase HS. It is suggested that the extractor is holding the case, maybe a claw extractor has more clearance and WOULD allow the case to move forward. Then it becomes a CLAW EXTRACTOR GUN phenomenon.
Another suggestion is to shoot 25 primed only cases and see if the primer-as-piston drives the case forward and increases HS.
We need a man with a claw-extractor rifle in a rimless and beltless caliber ex 308 and a cartridge headspace gauge to do some testing. If you'r out there, write me or us a post, volunteering.

Thanks to all;
joe b.

[Char-Gar]

Joe B. .... I have several 30-06 rifles with a claw extractors (03A3s and Win. 70) and I have a Wilson cartridge headspace gage in 30-06. Tell me what you want, but I am approaching my busy season, so It will be December or maybe even early January before I can get my round tuit.

[Larry Gibson]

First of all; when we refer to case headspace measurement and a shortening of this case headspace measurement it is a "decrease". The actual "headspace" which is the distance from the bolt face to a datum line on the chamber shoulder does not change. The headspace measurement is thought to "increases" because the difference between the chamber headspace measurement and the now shortened case headspace measurement has increased. This is caused by the "decrease" in case headspace measurement.

It is the primer detonation that drives the rimless case forward in light loads and sets the shoulder back decreasing case headspace measurement. This has been proven time and again by myself and many others before. It is also noticeable in rimmed cases as the primer will back out as much as the headspace allows (distance from bot face to chamber rim minus the thicknes of the case rim). With rimless cases the shoulder is set back by the force of the primer explosion driving the case forward and "sizing" the shoulder back if you will. How much the shoulder is set back per firing depends on numerous variables; hardnes of the case in the shoulder area, is the case fire formed, taper of the case, strength of the primer, size of the flash hole, etc, etc, etc. Controlled feed actions that are fed from the magazine will only allow the case headspace to decrease to the extent the extraxtor holds the case back. Snap over extractors will eventually not snap over as the case will be going to far into the chamber. Misfires occur when the firing pin no longer can reach the primer and strike it hard enough. With most claw extractor, bottom feed actions misfires do not occur because the extractor is holding the case back regardless of the case headspace. I have only encountered this problem with light cast bullet loads (generally those under 1500 fps) in cases using large size primers. I've not experienced it with cases (.222/.223) using small size primers.

Many of us learned to alleviate this problem by dedicating cases to this type of load and drilling out the flash hole. I use well fire formed cases and a #28 drill. Such cases are fired many many times without any increase (actually a decrease) in the headspace measurement of the case. Drilling the flash holes simply solves the problem. I have such cases, 30-06 for example, that have been fire countless times with 3 gr of Bullseye under a Lee TL314-90-SWC or the Hornady swaged .314 lead pistol bullet. I tracked 3 cases once and gave up measuring after 50 shots without significant change in cartridge headspace measurement. Without drilled flash holes the primers protruded after only a few firings and case headspace measurement decreased accordingly. I could contininue to use these cases in '03s and Mausers as the claw extractor still held the cases back enough for the firing pin to strike the primer. However, when used in a M721 Rem misfires occured as soon as 5 firings and the extractor would not snap over the rim. With flash hole drilled cases there was no longer any problem with shoulder set back in any rifle.

Other than drilling the flash holes you may use the old method of firing these loads once or twice per case then firing a full power load in the case to set the shoulder forward. That method however, induces case stretching in the web area and eventually leads to incipient head seperation. I shall continue to use cases with the flash holes drilled for such light cast bullet loads. I might mention that I recently have been using .308 cases with flash holes drilled with 170 gr cast bullets upwards of 2000 fps with 4895 without any pressure problem signs. I have been approching it quite cautiously and do not intend to go above the 2000 fps threshold. I've just been curious to see if my "regular" cast bullet loads in that bullet weight/velocity range would be safe with the flash hole drilled cases. So far no problem. I will continue to test.

Larry Gibson

[joeb33050]

Joe B. .... I have several 30-06 rifles with a claw extractors (03A3s and Win. 70) and I have a Wilson cartridge headspace gage in 30-06. Tell me what you want, but I am approaching my busy season, so It will be December or maybe even early January before I can get my round tuit.

Here's what I think is a reasonable test.
The question is: Does the firing pin hitting the primer knock the case forward,
Take a cartridge case that has "correct" headspace in the gauge, that has been fired in the test gun and not resized, and that "just" fits in the gun=a thin shim ~.004 on the bolt face allows no or only difficult closure with the firing pin out of the bolt.
The ctg. case used must be a close fit in the gun, a fired jacket fast load should make such a case.
"Kill" ~25 primers with oil, MMO works for me.
Remove the extractor.
Fire the case with a killed primer.
Knock it out with a rod.
Measure to see if the HS increased-if the shoulder moved back.
Check every ??, finally after the 25 are fired.

Here's the other test:
"Does the primer act as a piston, driving the case forward and increasing HS = moving the shoulder back?"
Get a good fitting case.
Prime it
Remove the extractor.
Fire the case/primer.
Check HS.
Fire again.
Measure
When 25 are done, see if and how much the difference is.

I'm thinking the whole test is a 2 hour effort.

Thanks; and tell me if I missed something here.
joe b.

[joeb33050]

Chargar and Larry Gibson;
I've read that drilling out the flash holes keeps the shoulder from moving back.
Also read that a #28 drill is the one to use.
With flash holes about .080" , primer dia. of .210" and #28 drill dia of .1405", some arithmetic shows us that the primer pocket-hole area goes from ~.03"^2 to .02"^2, a reduction of a third.
If the primer acts like a piston, it is kept from moving back by the bolt face, so the primer gas acts on the forward end of the primer pocket. the area is primer area - hole area.
So, if the #28 drill works, it tells us that the HS increase is caused by the primer pressure-not the firing pin. I think.
Only testing will tell.
I think we're on the track of the answer here, thanks to all for the help.
Any more testers out there?
joe b.

[Larry Gibson]

Chargar and Larry Gibson;
If the primer acts like a piston, it is kept from moving back by the bolt face, so the primer gas acts on the forward end of the primer pocket. the area is primer area - hole area.
So, if the #28 drill works, it tells us that the HS increase is caused by the primer pressure-not the firing pin. I think.
joe b.


Yup, that's what it does and what it tells us.

Larry Gibson

[Bullshop]

Wonder what would happen if you tried some cases with no flash hole?
I got some Win cases that way with no hole atall but they are rimmed.
You could prolly figure a way to do it but would it be safe? Primer compound is high explosive and like any other H.E. dont take well to being confined. So I guess in this case the whole brass case becomes the piston, yes?
BIC/BS

[mike in co]

In the next edition of the book there's a chapter 6.2.7 on headspace. I wrote a definition of the word based on commonly used and understood meanings of the word. Here's the definition:
"Headspace" is a word with a number of slightly different meanings all centering about the fit of a cartridge in a gun. There's the "mechanical drawing" definition of headspace, the difference between that definition dimension and the cartridge dimension (the tolerance, that allows us to chamber a cartridge), and "headspace" as the term for excess headspace that may cause trouble.

If you'd like to add to the chapter or revise it or edit it, I'd be happy for your input.
Our language changes all the time, both the written and the spoken language. Many-me too-resent this a little.
Also, there are some technically correct terms within a discipline that are not used "correctly" by the majority.
Physicists could properly describe all 2 or 3 pedals on the floor of an auto, and the round wheel we hang onto, as "accelerators", but they're kind enough not to.
Economists define "investment" as an addition to the capital stock, so when one buys shares of Amazon, one isn't investing-but is trading paper for paper.

I'm always looking to be corrected, anxious for it. Not this time, I don't think.
joe b.

what book ??
if you did not have others in the field proofread YOUR definition, then it is just that YOUR DEFINITION, and nothing else.
and answer my question......HEADSPACE is only listed on the chamber drawing, and not on the cartridge drawing ..correct ?? yes or no.....

your choice to use the term incorrectly does not make it correct or acceptable. as others have pointed out, the case may shorten, but HEADSPACE DOES NOT INCREASE in the testing you have described.
instead of continuing an error why not correct it ??

one last question.....
what is a head ?
yes i'm testing you.....

[scrapcan]

As much of the english language can reveal, words have different meanings, some valid and individual interpretation. Take for instance the term you asked. "What is a Head?"

It means something different if you are in the Navy or if you are a taxidermist. Not sure what happens if you are/were both.

It is my simple understanding that you set the headspace of the chamber and you fit the cartridge to that headspace. All the while hoping that there is some standard guiding the process (SAMMI Specs).

P.S Being a literalist (as I am apt to be also) can be frustrating. Most often the reason that scientific/engineering/technical types are not very good with idle conversation.

[joeb33050]

what book ??
if you did not have others in the field proofread YOUR definition, then it is just that YOUR DEFINITION, and nothing else.
.

"Cast Bullets For Beginner And Expert" published ~ 2 years ago by the CBA.
I'm working on the next edition, which is on castbulletassoc.org, then FORUM, then FILES.

I spend a lot of time asking for paragraphs, pages, articles, chapters, editing, etc, with little result.

Any help is welcome.
joe b.

[joeb33050]

Today, just now, 18 Nov., 2006 I took the Win M70 30/06 Post 64 and
taped a 2 liter pepsi bottle on the muzzle.
I took a cartridge case, took the firing pin out of the bolt, and
tried the case. No resistance to the bolt closing.
I made a .004" shim out of copier paper, put it on the bolt face, the
bolt wouldn't close with reasonable force.
Firing pin in , CCI 250 Magnum primer in the pocket, in the gun,
fired, a little pop.
Tried again with shim, no firing pin.
The bolt closed with no resistance. The primer drove the case forward.
Fired four more primers, made another .004" shim, both shims on the
bolt face and the bolt closed on the (primerless) case with a little
resistance.
It's the primers driving the case forward, not the firing pin strike.
Drilling the flash hole out (#28 drill) fixed the problem for some
folks, now I know why.
This is an easy test.
Extractor, exshmactor.
joe b.

[mike in co]

joe,
i went to look at the other site.....
it will not let me into files.....
even if i log in to a stupid yahoo user id.....

remember...just because i disagree with A statement you make does not mean that i think less of you. i assume you are a shooter and a cast shooter at that, all good things. i just disagree with a single statement you made....thats all.

[9.3X62AL]

Joe--

Your most recent post's text looks like valid evidence of the phenomenon you are exploring.

We sometimes forget just how powerful an impulse a primer provides. Earlier this year, I fired a Speer 75 grain J-word load in my Marlin 25-20 whose cartridge case contained no powder. It was driven up the bore ~6 inches by a small rifle primer, and was a RAT MUTHA to drive back out--thanks to Buckshot for that highly descriptive and appropriate adjective.

So--I have no trouble believing that the primer impulse alone could drive a case forward in the chamber with sufficient force to setback the shoulder. It would follow, then, that the load used in the firearm in question extend the boolit into the leade sufficiently to enable a zero clearance between boltface and case head, or have a pressure level high enough to fully expand the casing to chamber space specs, or both--if we are intent upon producing cases that fit closely to the chamber of the firearm in question.

[mike in co]

DEPUTY AL,
but what happens when there is no bullet/wad/etc.....nothing to contain the primer force in the case ??
his test is primer only.....
and firing pin on dead primer


mike
proud owner of a cz-97b.......
giggle giggle....

[9.3X62AL]

Mike--

I surmise that the primer itself has sufficient force against the primer cup's interior--even with the flash hole present-- to drive the case forward with enough force to set back the shoulder, thus causing a potential clearance issue. It could also be that repeated firing pin strikes on a deadened primer within a chambered case could have the same effect, although far slower in progression.

Not meaning to cause a misunderstanding with Joe here, but I do wonder how such an esoteric question applies to firing cast or j-word bullets in our rifles and handguns. The only time this issue would come to the fore is during the firing of really down-loaded cartridges, which many of us DO pursue--though it is outside my experience and hobby interest at present.

[hydraulic]

Several years ago I was shooting 10 grs. Unique/311413 as cast in a 7.7 Jap. using reformed .30-06 cases. After a few firings I had a misfire. I figured I had neglected to put powder in the case so took it home and pulled the bullet. No, I had not forgotten the powder so it must be a faulty primer. I dropped a nail in the empty case, set it on the edge of my press and hit it with a hammer. BOOM!!!
I had held the case with my little finger under the primer. The primer was blown out and went through the fleshy part of my finger and stuck just under the skin on the other side. I cut the skin with a razor blade, poured on some iodine and a bandaid and there isn't even a scar today. Shooting those light charges had caused the primer to set the shoulder back. I put a piece of scotch tape on the shoulder and the case fired. That hurt my little finger.

[9.3X62AL]

Joe--

Is your inquiry related to Tom Gray's article in "The Fouling Shot", pp. 184-12 to 184-13 ("308 VS. 30-30")? He makes a few assertions about pressure levels causing case changes that are diametrically opposed to my experience with the 243 and 250 Savage. This issue just arrived today, and I read it a few minutes ago.

[mike in co]

ok ...so lets make sure i have put 2 and 2 together.
primer pushes case forward, sets back the shoulder a little,( for some reason the powder charge may expand the case, but does not stretch to the bolt face) done several times the case is now short enough at the shoulder, that it will move forward and allow misfires due to lite/no primer hit ???

did i get it right ??

and joes second case is just striking a dead primer might move the shoulder back?
yes....??

i do not think i shoot anything in this catagory......


( joe...please note that the term used is setting the shoulder back......no reference to headspace. my opinion is that your guide would be more correct with this term, and no reference to changing case headspace..)

mike

[felix]

Al, what did Tom say in a nutshell? Easy to say? ... felix

[9.3X62AL]

If I read it correctly--in the 308 case, even at pressure levels in the 20K class--that pressure level is not sufficient to overcome or correct out the setback of the case shoulder that is set up by the firing pin strike. Essentially, this pressure level doesn't allow the case to expand/blow backwards to the boltface, as evidenced by smudging of case neck and shoulder areas.

THIS is the part that runs counter to my experiences in 243 and 250 Savage. And the 30-06, when it comes to that. Both of the smallbores use the same charge, 12.0 x 2400--both use boolit weights of 95-100 grains. Both run ~1700 FPS. Both are highly accurate. Neither has EVER smudged a neck, let alone a shoulder. Hence, my question to Joe about his query being prompted by this article.

Mr. Gray's article thrust is NOT about the 308, so much as about its relative merits compared to the 30-30--against which Mr. Gray feels the 308 falls a little short as a cast boolit chambering. With his core theme--308 vs. 30-30--I agree wholeheartedly, the 30-30 is a more useful and flexible chambering for castings than is the 308. His justifications for his position seem out of sync with my own experiences, though. Not to say he is mistaken--I don't think he wrote anything other than what he has honestly observed and recorded. It's just that his opinions and conclusions diverge from my own, that's all. With all the variables possible in this field, such a divergence shouldn't surprise us.

[joeb33050]

Light CB loads in rimless/beltless ctgs can result in excess headspace, ctg. to chamber.
Some claim firing pin drives the case forward. It doesn't. I checked. I KNOW.
Some suggest (NV Cur...) that neck sizing can move the shoulder back. I don't know.
Some say that the primer acts as a piston, driving the case forward/shoulder back. It does. I checked. I KNOW.
Some primer-piston guys say that drilling the flash hole out with a #28 drill fixes the problem.
I don't KNOW, but believe them and understand why that would work.
I don't have a gun that I shoot with these kind of loads right now.
HOW ABOUT TESTING LIGHT LOADS SO WE KNOW??? ANYBODY??
This hasn't got anything to do with seating the bullet out. If the HS has increased so that the primer doesn't go off, then increasing OAL may allow you to shoot the ctg., but it doesn't solve the problem.

joe b.

[Phil]

joeb33050 is exactly right. This was all done by the NRA staff in the fifties. We're trying to reinvent the wheel here guys. The NRA staff proved that the primer drove the case forward shortening the body of the case. They also proved in semi-auto's like the Garand that the bolt cycling drove the case into the chamber hard enough to shorten the body. I think thats why Garand headspace is held to closer tolerances than SAAMI data.

By the way, SAAMI specs, in a lot of cases, is a JOKE!!!! There is nothing holy about SAAMI at all.

Cheers,

Phil

[joeb33050]

Phil;
Vague allusions to what somebody did at NRA in the fifties is like saying what a friend of your cousin did in the fifties. Without a cite it's your memory of what you think somebody said. Not good enough for me, I'm interested in DATA, in fact, in the cite. The test is easy.
I'm from Missouri.
joe b.

[joeb33050]

Joe--

Is your inquiry related to Tom Gray's article in "The Fouling Shot", pp. 184-12 to 184-13 ("308 VS. 30-30")? He makes a few assertions about pressure levels causing case changes that are diametrically opposed to my experience with the 243 and 250 Savage. This issue just arrived today, and I read it a few minutes ago.
I had to read the article again.
Yes but no. Tom and I differ on what makes the HS increase, he has several times referenced his test (with the 03/A3 I think) and I tried twice but wasn't able to duplicate his results. My third test convinced me. I know it's the primer.
My inquiry is about getting that part of the book put to bed, and it is and I did. Not sparked by Tom's article. He's right about the 30/30. Brass is easy to find and cheap, there are more .30 molds than any other, the case is fairly small, it's rimmed to eliminate any HS change with light loads, the neck is long enough for ~any bullet. Whjat's not to love? Why folks make .32 SS rifles is beyond me.
I love the 30/30, I had a Hepburn barreled by Bud Welsh in 30/30, now have a Martini in 30/30, and a M54 in 30/30.
I agree with Tom that it would be a great CB gun in a Savage in 30/30.
I don't understand Tom's measuring business, surface plate and height gauge. But, add a straight edge to run the base against and I see how a change in HS can be easily measured.
But, clearly the .308 is a pretty good CB ctg. See the CBA results.
joe b.

[Phil]

Phil;
Vague allusions to what somebody did at NRA in the fifties is like saying what a friend of your cousin did in the fifties. Without a cite it's your memory of what you think somebody said. Not good enough for me, I'm interested in DATA, in fact, in the cite. The test is easy.
I'm from Missouri.
joe b.

One of the most ignorant statements I've read in the last twenty years!

Phil

[felix]

OK, guys, it appears from all of the discussion so far that the firing pin does indeed cause a change in case datum. The firing pin itself can be aided by the actual primer explosion blowing the case foward, by having too small of a primer hole, or by the contents within the case acting as a constriction to the advancing force wave, or both. So, by opening up the primer hole, or by sticking the boolit hard into the lands, or both, should aid in circumventing some compression of the datum. It therefore stands to reason that the powder speed can be increased to eliminate a measured datum change. ... felix

[Larry Gibson]

Light CB loads in rimless/beltless ctgs can result in excess headspace, ctg. to chamber.
HOW ABOUT TESTING LIGHT LOADS SO WE KNOW??? ANYBODY??
joe b.

I've been conducting that experiment for years.

I shoot litterally thousands of Lee TL314-90-SWCs, Hornady .314 swaged lead, Speer .32 cal HBWCs over 2.7 to 3 gr of Bullseye in rimless case; 7.63x39, .308, 30-06 and 7.65 Argentine. I also have shot them in .30 Rem, .300 Savage and 7.7 Jap (probably a couple more I'm not remembering). I ALL instances, even with well fire formed cases, headspace of the case decreased consistantly with each firing. Misfires were most often not encounter with controlled feed actions. However with push feed actions misfires occur in as little as 3-5 firings. In every instance drilling of the flash hole stopped the shoulder set back.

The exception is 7.62x39 with R-P cases using SR primers. I've yet to experience shoulder set back with the load mentioned even after 50 firings in a bolt action Mini Mk X rifle. But switch to IMI or W-W cases using LR Primers and shoulder set back occurs just like othe rimless cases using a LR primer.

Larry Gibson

[Maven]

All, I've been reading this thread with interest and am prompted to ask whether the specific brand of brass, i.e., its hardness/softness, is a relevant variable?

[mike in co]

Phil;
Vague allusions to what somebody did at NRA in the fifties is like saying what a friend of your cousin did in the fifties. Without a cite it's your memory of what you think somebody said. Not good enough for me, I'm interested in DATA, in fact, in the cite. The test is easy.
I'm from Missouri.
joe b.


for a man that says he wants DATA, i find it amazing that when you are given DATA you stick your head in the sand and ignore DATA.
maybe this is the problem people on this board have with what goes on with CBA and thier site.
you claim you are witting a book, an educational tool for new cast boolit shooters. pull your head out of the sand!
saami is our national standard that very clearly states that the term HEADSPACE applies to chamber size PERIOD. THERE IS NO MENTION OF THE TERM HEADSPACE IN THE CARTRIDGE DRAWING.
when you READ the instructions that come with most reloading dies, the words very clearly speak of how much SIZING of the case take place. nowhere do these die makers talk of changing headspace by sizing brass.
if you publish YOUR definition of brass sizing as headspace you are doing the entire world of cast boolit shooting a disfavor and embarassing most of us in front of the rest of the shooting world.
think before you act.

[felix]

Yes, Maven, it definitely would be. Also, the thickness of the brass at the datum point must be considered as well. The 30-30 case is sorta' thin up there and that characteristic in particular would be entirely suspect if it were not for the rim stopping the foward movement of the case upon firing. ... felix

[felix]

One of these days, Larry, someone might manufacture a series of primers where one can select force and heat independently. That time has come! The 41 mag would be a much better round with small primers as the primer selection stands today. ... felix

[felix]

Thinking a little about it, Larry, why not try some forceful primers in the steel Wolf brand cases? No, they won't hurt the dies provided the poly is still intact throughly on the cases. Winchester large rifle magnum are the most forceful out there, circa 1995 lots. ... felix

[9.3X62AL]

Joe--

I can understand your esoteric interest in the subject matter, and the hunt for finality and certainty as to cause and origin. You'll note that Mr. Gray states his belief that the firing pin strike absent the influence of primer impulse can cause clearance to expand. I suppose that is possible--cartridge brass is malleable, and repetition of strikes over time could conceivably set the case shoulder back measurably. I share your view that the primer impulse would be a more telling cause of that phenomenon.

I think it is pretty clear that light loads in rimless/beltless cases can produce excessive chamber clearance problems, by whatever name we choose to label it. A rimmed case is likely a better container for such loads, and an answer for those of us shooting the rimless rounds is to alternate the cases used for light loads with warmer or full-value loadings every other firing, to address the onset of excessive clearance issues.

Anyone trying to classify the 308 Winchester as unsuitable for cast boolits--or any other type of target work that it qualifies for--is taking on a long contract, for sure.

Given all the possible variables involved in this issue, I think the best response to relate to a readership would be to state the matter factually--absent the absolutes you are seeking to nail down. Those variables really cause havoc for someone seeking solid answers. Larry's report bears this out--substitute one element (case make), and the phenomenon disappears in his rifle. Like so much of this hobby field, it is a lot more art than science--owing largely to the variables in three dimensions we deal with as a part of this pursuit. Perhaps the best we can do is to state this CAN occur, and list the factors leading to its occurrence--rather than trying to firmly nail down "how to produce it" and asserting that the condition WILL TAKE PLACE. My overall impression of this hobby field is that very few "absolutes" can be found within it.

[Bass Ackward]

Joeb,

Before you stress out, let me throw you a bone. My buddies 98 Mauser chambered in 35 Whelen did lose headspace with light loads. We changed the heavy steel firing pin with a blunt end out with a titanium one with a finer point and so far it hasn't.

A lot of tests that we do in the shooting sports look for absolutes. And this may be one of those disappointments. I suspect that firing pin blow force, point shape, and action type may make the difference. As someone else suggested, I would think that a push feed would be more vulnerable to this but it would depend on how well it fit the rim. Along with primer brand.

Take my Savage which is a 35 Whelen. I can adjust the firing pin spring force so that it detonates Remingtons and Federals everytime but every other CCI will hardly have a dent and of coarse fail to fire. I never see any reduction. Period. But remember, I also shoot pistol primers exclusively. So with the harder cups of CCI rifle primers, if you were going to get headspace reduction, it should be seen on CCIs before any other brand.

So trying to find out if firing pins actually change cartridge headspace on rimless cases is like asking if cast bullets lead. Maybe for some folks they do ................

[swheeler]

Firearms Encyclopedia
By George C. Nonte, Jr.
Copyright C 1973

Headspace: (1) In a gun, the distance from the breech face or bolt face to that portion of the chamber or barrel that supports the cartridge.
(2) In a cartridge, that distance between the rear face of the case head and the forward face of the surface which arrests it's movement into the chamber.

Page 130

Hummmm

[mike in co]

Firearms Encyclopedia
By George C. Nonte, Jr.
Copyright C 1973

Headspace: (1) In a gun, the distance from the breech face or bolt face to that portion of the chamber or barrel that supports the cartridge.
(2) In a cartridge, that distance between the rear face of the case head and the forward face of the surface which arrests it's movement into the chamber.

Page 130

Hummmm

thank you but it is the same ol stuff.....look at how poorly described his definition is....."...to that portion of the chamber or barrel that supports the cartridge."
excuse me.....the chamber walls support the case, the neck portion supports the case.

his cartridge definition is almost correct for headspace of a chamber for a rimmed cartridge......front and back of the rim is headspace..... which in turn shows just how bad his "gun" definition is.....
keep looking....but why are you looking any where but were the STANDARDS for the american fire arms industry are written.
in the United States SAAMI is the standard for chamber and cartridge specs....and again...only one of those two drawings has the word headspace in it, and that is the chamber drawing.

of course, joe could submit HIS definition to SAAMI and if they accepted it,then he would be correct.........

this is not MY definition, it is the industry's definition.

answer me this......
why isnt a full length sizing die called a headspace setting die ????
why isnt a shoulder bump die called a headspace setting die ???

we size cases to fit our chambers.....and for the most part we do not know nor care what the actual headspace dimension of the firearm is.

the fact that joe will not go look at published NRA data on his chosen subject, tells me he is not interested in ALL DATA, but only data which supports his opinion.
my 1981 copy of NRA'S handloading CONTAINS DATA on case shortening due to repeated firing of low power loads.( maybe he is not interested because it discusses CASE SHORTENING, AND NOT HEADSPACE INCREASE...ouch)

[joeb33050]

for a man that says he wants DATA, i find it amazing that when you are given DATA you stick your head in the sand and ignore DATA.
maybe this is the problem people on this board have with what goes on with CBA and thier site.
you claim you are witting a book, an educational tool for new cast boolit shooters. pull your head out of the sand!
saami is our national standard that very clearly states that the term HEADSPACE applies to chamber size PERIOD. THERE IS NO MENTION OF THE TERM HEADSPACE IN THE CARTRIDGE DRAWING.
when you READ the instructions that come with most reloading dies, the words very clearly speak of how much SIZING of the case take place. nowhere do these die makers talk of changing headspace by sizing brass.
if you publish YOUR definition of brass sizing as headspace you are doing the entire world of cast boolit shooting a disfavor and embarassing most of us in front of the rest of the shooting world.
think before you act.

Mike;
Tell me the issue, or send me a copy, or tell me the year; and I'll try to find the DATA, but without a clue, it's a guess.
About HEADSPACE, give it a rest, nobody cares. You're pouting and it ain't pretty.
joe b.

[joeb33050]

One of the most ignorant statements I've read in the last twenty years!

Phil

Phil;
Have you got a cite?
You must not read much.
joe b.

[joeb33050]

OK, guys, it appears from all of the discussion so far that the firing pin does indeed cause a change in case datum. The firing pin itself can be aided by the actual primer explosion blowing the case foward, by having too small of a primer hole, or by the contents within the case acting as a constriction to the advancing force wave, or both. So, by opening up the primer hole, or by sticking the boolit hard into the lands, or both, should aid in circumventing some compression of the datum. It therefore stands to reason that the powder speed can be increased to eliminate a measured datum change. ... felix

Felix;
Mike is going to get on you about "case datum".or "Compression of...".
No, the firing pin did NOT increase HS or move the shoulder back in any of my tests. No.
Yes, the primer drives the case forward, moving the shoulder back and increasing bolt-case clearance, sometimes called HS.
No, the primer hole = flash hole isn't too small, it's the way it comes, ~.080" dia.
I don't know anything about "the contents within the case acting as a constriction to the advancing force wave", never heard of this before? Have you any info on this?
Yes, opening the flash hole keeps the shoulder where it is, see the post re DATA on this.
No, sticking the bullet hard into the lands doesn't keep the HS from increasing, at least as far as I know. Should be an easy test to do.
Your powder speed conclusion makes no sense to me. All slow speed CB loads are with fast powders, that's what the whole topic is about. I don't know that we can use faster powder and stop the process, do you? Faster than Unique or BE?

joe b.

[joeb33050]

I've been conducting that experiment for years.

I shoot litterally thousands of Lee TL314-90-SWCs, Hornady .314 swaged lead, Speer .32 cal HBWCs over 2.7 to 3 gr of Bullseye in rimless case; 7.63x39, .308, 30-06 and 7.65 Argentine. I also have shot them in .30 Rem, .300 Savage and 7.7 Jap (probably a couple more I'm not remembering). I ALL instances, even with well fire formed cases, headspace of the case decreased consistantly with each firing. Misfires were most often not encounter with controlled feed actions. However with push feed actions misfires occur in as little as 3-5 firings. In every instance drilling of the flash hole stopped the shoulder set back.

The exception is 7.62x39 with R-P cases using SR primers. I've yet to experience shoulder set back with the load mentioned even after 50 firings in a bolt action Mini Mk X rifle. But switch to IMI or W-W cases using LR Primers and shoulder set back occurs just like othe rimless cases using a LR primer.

Larry Gibson
Larry;
This is exactly what I'm looking for, the kind of information that I can use with comfort in the book.
Did you mean "...headspace of the case INcreased constantly with..."?
Thanks I'm putting this in the section in the book.
joe b.

[joeb33050]

the fact that joe will not go look at published NRA data on his chosen subject, tells me he is not interested in ALL DATA, but only data which supports his opinion.
my 1981 copy of NRA'S handloading CONTAINS DATA on case shortening due to repeated firing of low power loads.( maybe he is not interested because it discusses CASE SHORTENING, AND NOT HEADSPACE INCREASE...ouch)

Mike;
How about scanning and sending, or copying and mailing, this info. I'm very interested.
Thanks;
joe b.

[mike in co]

Mike;
Tell me the issue, or send me a copy, or tell me the year; and I'll try to find the DATA, but without a clue, it's a guess.
About HEADSPACE, give it a rest, nobody cares. You're pouting and it ain't pretty.
joe b.

SAAMI drawings can be obtianed from:
SAAMI
po box 218
Wallingford, CT 06492

I'M NOT POUTING
I AM DISGUSTED WITH A PERSON THAT CLAIMS TO BE A SHOOTER, CLAIMS TO BE A CAST BOOLIT SHOOTER, WANTS TO BE A PUBLISHED AUTHOR, BUT IS SO CLOSED MINDED , THAT RATHER THAN CORRECT AN ERROR , HE HAS DECIDED TO PUBLISH THE ERROR, THUS MAKING HIS ERROR EVEN WORSE.

i notice you choose to ignore every question i have presented to you that supports the saami std definition of headsapce. if your version of headspace is correct, why is it that EVERY die maker on the market talks of "SIZING CASES", NOT "SETTING HEADSPACE" ??

IT WOULD APPEAR TO ME, THAT YOU ARE WILLING TO ACCEPT DATA THAT SUPPORTS YOUR VIEW, BUT IF IT IS DIFFERENT THAN YOUR VIEWS IT IS NOT "DATA".

MIKE

[Larry Gibson]

Larry;
This is exactly what I'm looking for, the kind of information that I can use with comfort in the book.
Did you mean "...headspace of the case INcreased constantly with..."?
Thanks I'm putting this in the section in the book.
joe b.

Yes, I went with the common misconception that a shortening of the headspace of a cartridge case "increases" headspace. It seems that is understood better than the cartridge case headspace actually decreases. I guess I shall just be pragmatic in the future and stick with the fact that it' does indeed decrease. Thanks for setting me straight.

Larry Gibson

[joeb33050]

Yes, I went with the common misconception that a shortening of the headspace of a cartridge case "increases" headspace. It seems that is understood better than the cartridge case headspace actually decreases. I guess I shall just be pragmatic in the future and stick with the fact that it' does indeed decrease. Thanks for setting me straight.

Larry Gibson

I'm not trying to be the boss of the language. As I said, I see three slightly different meanings for the word "headspace" in the literature, and hear them during discussions. I think it's better to INCLUDE the different definitions rather than EXCLUDE one or two.
Again, I'm needing readers and editors to keep me/us straight, and welcome any volunteers.
joe b.

[mike in co]

Yes, I went with the common misconception that a shortening of the headspace of a cartridge case "increases" headspace. It seems that is understood better than the cartridge case headspace actually decreases. I guess I shall just be pragmatic in the future and stick with the fact that it' does indeed decrease. Thanks for setting me straight.

Larry Gibson

actually i think larry's reply is an excellent case of what happens when the term is mis-used. look at the confusion caused .
if the correct terms had been used there would be no such confusion.
you and i cannot on a normal basis change headspace, you me and the rest of the world can SIZE cases to change the fit within the chamber.

we look for precision in our shooting, this is a case where some precision in our words would work better for all.

[swheeler]

we look for precission in our shooting, this is a case where some precission in our words would work better for all.
This is where we differ, I look for precision!

[mike in co]

we look for precission in our shooting, this is a case where some precission in our words would work better for all.
This is where we differ, I look for precision!

noted...and corrected...unlike some other person....oppssss

[joeb33050]

Here's where I am now. Looking for comments/criticism/correction.
joe b.
6.2.7.1 INCREASING HEADSPACE WITH SLOW CAST BULLET LOADS

It is often said that shooting cast bullets at low velocities in not-rimmed-or-belted cases increases headspace. It has happened to me.
One explanation is that the firing pin strike drives the caseforward, moving the case back and increasing headspace. I've never been able to make this happen in two previous tests.
On 11/16/06, I did this test for the third time on the third gun, a Win M70 Target 30/06 Post 64 rifle.
I "killed" 26 CCI 250 Magnum primers with marvel mystery oil. (I did this test at home, in the condo.)
Put an empty fired case in the gun.
Removed the firing pin from the bolt.
The bolt closed easily on the case.
Made a .004" copier paper patch to fit the bolt face, put it on the bolt face, the bolt would not close with a little pressure.
After testing and fiddling and firing 26 primers in that one case, the bolt closed easily on the fired case-wouldn't close with a little pressure with the paper patch on the bolt face.
Others have increased headspace with the firing pin striking the primer, but I can't and this is the third time I've done this test.

Another explanation is that the primer acts as a piston in the primer pocket cylinder, the primer pressure acting on the primer pocket-less the flash hole. If true, firing 25 or so primed-only cases should move the shoulder forward and increase headspace.

On 18 Nov., 2006 I took the Win M70 30/06 Post 64 rifle and taped a 2 liter Pepsi bottle on the muzzle.
Put an empty fired case in the gun.
Removed the firing pin from the bolt.
The bolt closed easily on the case.
Made a .004" copier paper patch to fit the bolt face, put it on the bolt face, the bolt would not close with a little pressure.
Firing pin in , CCI 250 Magnum primer in the pocket, in the gun, fired, a little pop.
Tried again with the paper shim, no firing pin.
The bolt closed with no resistance. The primer drove the case forward.
Fired four more primers, made another .004" shim, both shims on the
bolt face and the bolt closed on the (primerless) case with a little resistance.
It's the primers driving the case forward, not the firing pin strike.

Drilling the flash hole out (#28 drill) fixed the problem for some folks, now I know why.
A large primer pocket is .210" diameter, area is .035"^2 (square inches).
Standard flash hole diameter is .080", area is .005"^2.
#28 drill diameter is .1405", area is .016"^2.
With a standard flash hole the primer acts on .035-.005 = .030"^2.
With the flash hole drilled #28, the primer acts on .035-.016 = .019"^2.
This change, we're told, keeps the primer from driving the case forward, the shoulder back, and increasing headspace.
"I shoot literally thousands of Lee TL314-90-SWCs, Hornady .314 swaged lead, Speer .32 cal HBWCs over 2.7 to 3 gr of Bullseye in rimless case; 7.63x39, .308, 30-06 and 7.65 Argentine. I also have shot them in .30 Rem, .300 Savage and 7.7 Jap (probably a couple more I'm not remembering). I ALL instances, even with well fire formed cases, headspace of the case decreased consistently with each firing. Misfires were most often not encountered with controlled feed actions. However with push feed actions misfires occur in as little as 3-5 firings. In every instance drilling of the flash hole stopped the shoulder set back.

The exception is 7.62x39 with R-P cases using SR primers. I've yet to experience shoulder set back with the load mentioned even after 50 firings in a bolt action Mini Mk X rifle. But switch to IMI or W-W cases using LR Primers and shoulder set back occurs just like other rimless cases using a LR primer."
Larry Gibson


There's a third theory on this shoulder setback; that neck sizing in a rough sizing die may set the shoulder back. See below and also Ed Wosika's comments in ON HEADSPACE.

NV Curmudgeon on Cast Boolits writes: "Let me tell you what I found by emperical means. I have a rebarreled Ruger 77 in .35 Whelen. There is never a bit of case fit trouble when firing full power loads. I use full power cases until I am bored with them. Using my standard CB load of 20.0 X 2400 and a 213 gr. (actual weight) NEI 220358 boolit at a mv of 1700 fps, and PARTIAL FULL-LENGTH SIZING, I begin having misfires around the tenth firing. This occurs with either Rem. .35 Whelen cases or cases formed from Rem. .270s. The Wilson case gauge then shows a reduction in head to datum line measurement. I next bought a Redding (real) neck sizing die. So far the group of cases that I am watching are still sure-fire after 17 firings. My wild guess is that the partial full-length sized, low pressure loaded, cases are not obturating as well as desired, and that the P.F.L.S. is exacerbating the situation by very gradually setting back the shoulder."

[mike in co]

Mike;
How about scanning and sending, or copying and mailing, this info. I'm very interested.
Thanks;
joe b.

my scanner is is not working, or i would.
on the other hand you could contact the NRA, it is my understanding that the book is still in print. the original post has the title and the print date
mike

[swheeler]

One explanation is that the firing pin strike drives the caseforward, moving the case back and increasing headspace.

case forward, moving the case shoulder/datum line back

[joeb33050]

One explanation is that the firing pin strike drives the caseforward, moving the case back and increasing headspace.

case forward, moving the case shoulder/datum line back

We deal with this notion above. I can't make it happen, Tom Gray can. Can any of you?
joe b.

[joeb33050]

noted...and corrected...unlike some other person....oppssss

Mike;
You obviously feel strongly about this.
How about this. Write us about what the word means and why you say what you do-the citations. I will then include it in both the headspace article and the article we're talking about. All in the book. A couple of paragraphs. Mike Wheeler, right? for attribution.

joe b.

[swheeler]

Here's where I am now. Looking for comments/criticism/correction.
joe b.

correction, you asked. The Mike Wheeler comment is uncalled for, we are all adults here, I think?

[mike in co]

joe,
SAAMI only lists HEADSPACE on the chamber drawing, not in the cartridge drawing.
Every manufacture of reloading dies talk of SIZING cases with SIZING dies. not one of them has an optional use with the word adjusting HEADSPACE in thier instructions.
i have a lot of reloading manuals, most powder reloading books, and two european manufactures books. not one of them, in thier case prep/reloading sections use the words you propose.
other than your own personal use of the words, can you at least see the logic of my statements ? do you have the ability to step back and look without prejudging?

do any lights come on when the entire industry has one definition and joe says something else ??

mike

[mike in co]

Headspace
From Wikipedia, the free encyclopedia
Jump to: navigation, search

Headspace of a .45 ACP cartridge, headspacing off the case mouthIn firearms terms, headspace refers to the distance between the bolt face and chamber necessary for reliable functioning of the weapon, or as a verb, the mechanism by which the correct positioning is achieved.

The headspace is the distance measured from the part of the chamber that stops forward motion of the cartridge, usually called the datum line, to the face of the bolt. Different cartridges have their datum lines in different positions in relation to the cartridge. For example, 5.56 NATO ammunition headspaces off the shoulder of the cartridge, whereas .303 British headspaces off the rim of the cartridge.

Headspace is measured with a set of headspace gauges. Each caliber gun typically has a "go" gauge, a "no-go" gauge, and, especially for current or former military calibers, a "field" gauge. On non-military surplus (that is, commercial) firearms, the bolt must lock on the "go" gauge, must not lock on the "no-go" gauge, and must not lock on the field gauge.

For military surplus firearms, there is a bit more latitude in the "no-go" gauge, as it may indicate correctly for commercial firearms, but may be overly-tight in tolerance for checking military-surplus guns designed to operate safely with a wider range of ammunition tolerances. For a military surplus gun that has a bolt lock on the "no-go" gauge, but that will not lock on the "field" gauge, the firearm may be perfectly safe firing military ammunition with heavier wall-thickness brass, but may have a tendency to overstress brass on commercial ammunition. At the very least, a military surplus firearm that locks on the "no-go" gauge and not on the "field" gauge will be difficult to reload for, as the brass will likely not last for more than one or two reloadings before cracking during re-sizing. An alternative approach for shooting a military-surplus gun is simply not to re-load commercial brass cartridges for it.

Any military-surplus gun that does lock on a "field" gauge, however, is unsafe to fire, and should be checked by a trained gunsmith.

Guns that fail to lock on the "go" gauge may simply need cleaning, especially at the bolt face, as build-up may occur on this surface and cause problems in chambering a round without stressing the brass.

There can be other types of gauges that measure exactly how over or undersize a chamber might be.

Headspace is important for the proper functioning of the firearm. If the headspace is too short, ammunition that is in specification may not chamber correctly. If headspace is too large, the cartridge case may rupture, possibly damaging the weapon and or possibly injuring the shooter. Some military-surplus firearms are designed to safely handle a case rupturing, whereas other military-surplus firearms may not be able to safely handle such an event. When in doubt, always seek a trained gunsmith to check headspace before firing any gun, but especially before firing any used gun.

Retrieved from "http://en.wikipedia.org/wiki/Headspace"
Categories: Firearm actions | Ammunition

[mike in co]

HEADSPACE
The distance from the face of the closed breech of a firearm to the surface in the chamber on which the cartridge case seats.


HEADSPACE GAGE
A device used in a firearm to determine the distance between the breech face and the chamber surface on which the cartridge seats. Also called Breeching Plug.

CARTRIDGE
A single round of ammunition consisting of the case, primer and propellant with or without one or more projectiles. Also applies to a shotshell.


CARTRIDGE BLOCK
A flat container having blind holes into which cartridges can be inserted in an upright position to be readily available to the shooter.


CARTRIDGE CASE
The main body of a single round into which other components are inserted to form a cartridge. Usually refers to centerfire and rimfire cartridges. Serves as a gas seal during firing of the cartridge. Usually made of brass, steel, copper, aluminum or plastic Also referred to as a shellcase.


CARTRIDGE CASE LENGTH
The dimensions from face of the head to the mouth.


CARTRIDGE CASE SIZING
See Sizing.
SIZING
1. The reduction in diameter of a bullet by forcing it through a die of smaller diameter than the bullet.
2. The reduction in diameter of a cartridge case by forcing it into a die of smaller diameter than the case.


SIZING DIE
A tool used to form a cartridge case or bullet to proper dimensions.


SIZING, FULL LENGTH
The operation of reforming a fired cartridge case to approximately its original dimensions.


SIZING, NECK
The operation performed by reloaders to reduce or restore the original neck diameter of a fired cartridge.

[fourarmed]

Joe, I used to use a Wichita International silhouette pistol chambered in 7mmInt-R, which as you probably know, is a rimmed wildcat based on the .30-30 case. My load was 17 gr. of 4759 with a 140 grain bullet. This load shortened cases until primers protruded about .010" to .020" after firing. I never had a case separation, so I eventually quit worrying about it. I can only assume that the headspace was excessive on this pistol, as you normally don't hear about this problem with rimmed cases.

[mag_01]

:coffee: ---Primers backing out is the 1st sign of headspace problem---2nd stage primers are driven back in (looks normal)-----3rd stage case separation-----Mag

[mike in co]

:coffee: ---Primers backing out is the 1st sign of headspace problem---2nd stage primers are driven back in (looks normal)-----3rd stage case separation-----Mag


i'd like to agree with you , but it aint so......
as is being discussed here a gun with proper headspace, may with certain loads cause the case to shorten.
and certain loads will allow a primer to backout even with a gun with correct headspace.

its all part of the reloading hobby most of enjoy...

[joeb33050]

Here's where I am now. Looking for comments/criticism/correction.
joe b.

correction, you asked. The Mike Wheeler comment is uncalled for, we are all adults here, I think?

Sorry, S. Wheeler. These noms de plume confuse me. I thought that mike in co was Mike Wheeler, I don't like to use the mike in co names in the book. My error, not any thing else.
Joe Brennan
I think I'll sign all my posts this way from now on

[joeb33050]

One explanation is that the firing pin strike drives the caseforward, moving the case back and increasing headspace.

case forward, moving the case shoulder/datum line back

I guess I wasn't clear on my first response.
Others, including T. Gray, report the firing pin moving the shoulder back.
I did three tests, three rifles, and can't make it happen.
I CAN drive thhe shoulder back with the primer, firing a primed-only case.
Therefore, in my guns, in my tests, it's the primer-not the firing pin.
I'd like for some other/s to try the test with maybe an 03 or 03/a3.
This test takes ~15 minutes.
Joe Brennan

[mike in co]

I'm not trying to be the boss of the language. As I said, I see three slightly different meanings for the word "headspace" in the literature, and hear them during discussions. I think it's better to INCLUDE the different definitions rather than EXCLUDE one or two.
Again, I'm needing readers and editors to keep me/us straight, and welcome any volunteers.
joe b.


you have been given sisgnificant input, correction and editing.
just what you asked for.

can you show the rest of us recognized sources that have used YOUR DEFINITION ?

PROVE ME WRONG, OPEN YOUR EARS, CLOSE YOUR MOUTH AND ACTUALLY LEARN SOMETHING .

mike
ps for the record, cba is not a recognized source on this board, and niether is fulton armory. fulton armory by itself ruined the highpower board on the old shooters.com. thier ill advised suggestions, lack of knowledge of what was required for high power competition, shill posts drove the core of knowledge out of the board. the good news is that the hard core members started a new site which today is just what a user site should be.

[carpetman]

HEADSPACE---The area on a ship taken up by latrine(toilet) facilities.

INCREASING HEADSPACE-- A phenomenon that occurs when female personnel are included in the crew. Caution must be used that you don't go overboard with this. Going overboard would include not having lets say a galley(kitchen). Tempers seem to flare when there is no kitchen.

DECREASING HEADSPACE---If done to the point that male/female personnel share the same facility,it tends to increase male morale and decrease morale in a few female personnel (most of the female personnel will also have increased morale). Going overboard will cause the men to ---well--go overboard.

These definitions have not been approved by the CBA.

[joeb33050]

Joe, I used to use a Wichita International silhouette pistol chambered in 7mmInt-R, which as you probably know, is a rimmed wildcat based on the .30-30 case. My load was 17 gr. of 4759 with a 140 grain bullet. This load shortened cases until primers protruded about .010" to .020" after firing. I never had a case separation, so I eventually quit worrying about it. I can only assume that the headspace was excessive on this pistol, as you normally don't hear about this problem with rimmed cases.

My 32/35 Maynard has about .005" excess space between the breech and the head of cartridges made from 32/40s.
In the ASSRA Journal there was a series of articles on oddball cartridges and what one could make them from. Several times I noted that the design rim thickness on the suggested parent cartridge was substantially smaller than that on the new cartridge.
I've often read that rimmed ctgs headspace on the body or neck after shooting, some are very definite on this. I never figured out how to tell. Maybe it's true.
Your pistol must have had a lot of excess clearance, and didn't seem to headspace on the neck after shooting. Maybe that is just another old wives tale, about HS on the neck after firing, or your gun would have done it.
My experience with the Contender and headspace and getting the gun to close was enough to make me sell it after 32/20, 30/30, 7TCU, 6.5TCU and other barrels-something very funny goes on with the Contender and HS, muh has been written.
So much to learn!
joe b.

[joeb33050]

you have been given sisgnificant input, correction and editing.
just what you asked for.

can you show the rest of us recognized sources that have used YOUR DEFINITION ?

PROVE ME WRONG, OPEN YOUR EARS, CLOSE YOUR MOUTH AND ACTUALLY LEARN SOMETHING .

mike
ps for the record, cba is not a recognized source on this board, and niether is fulton armory. fulton armory by itself ruined the highpower board on the old shooters.com. thier ill advised suggestions, lack of knowledge of what was required for high power competition, shill posts drove the core of knowledge out of the board. the good news is that the hard core members started a new site which today is just what a user site should be.

What does it mean about CBA?
Here's what I got in 10 minuites on google.

"Headspace" is the distance between the face of the breech and the base of the cartridge when the action is closed, and excessive headspace can be dangerous as well as impair accuracy."
From the Forster page, on the net, on headspace gages.

"In practical terms, headspace is the clearance allowed between the base of the cartridge case and the face of the bolt."
From The Gunroom, a MSN site.

"When a cartridge having insufficient headspace is chambered, the action will be blocked from fully closing. Conversely, when a condition of excessive headspace exists, there will be some amount of linear “play” of the cartridge within the chamber when the action is closed. As a practical matter, some amount of headspace must be present to assure reliable operation and chambering. In most modern ammunition, this will be something on the order of four to six thousandths (.004" to .006") of an inch."
From www. exteriorballistics.com

"I have measured many, many types/manufacturers of commercial and NATO ammo via cartridge "headspace" gauges as well as "in rifle" checks."
Clint McKee at Fulton Armory site.

"When you use the Mic,your sized-case headspace needs to be about .001-in. less than what a normal, fired, new case has after it's been fired in your chamber."
Bart Bobbitt

See the armalite library headspace definitions.

Measure cartridge headspace with a caliper? Absolutely! With this affordable gauge, it's as easy as measuring trim length. ...
www.stoneypoint.com/headspace_


There's much more if you want it.
joe b.

[Larry Gibson]

Measure cartridge headspace with a caliper? Absolutely! With this affordable gauge, it's as easy as measuring trim length. ...
www.stoneypoint.com/headspace_

There's much more if you want it.
joe b.

I've been using the Stoney Point tool for years, it's how I know when there is an increase or decrease in cartridge headspace as discussed in this thread. I highly recommend the use of this tool.

Larry Gibson

[mike in co]

What does it mean about CBA?
Here's what I got in 10 minuites on google.
I LOGGED ON THIS AM, READ THIS AND WENT SHOOTING...IMPORTANT THINGS FIRST.
JOE YOU DO PROVIDE GOOD ENTERTAINMENT VALUE.

LETS LOOK AT YOUR "SOURCES"
IN MY LAST POST I TOLD YOU TWO SOURCES WERE UNACCEPTABE
CBA AND FULTON ARMORY......FULTON ARMOUR AND MCKEE ARE SUCH JOKES IN THE FIREARMS INDUSTRY THAT I WOULD NOT LET YOU BUY A RIFLE FROM THEM.
SO OF YOUR ORGINAL 7 YOU ARE DOWN TO 6


"Headspace" is the distance between the face of the breech and the base of the cartridge when the action is closed, and excessive headspace can be dangerous as well as impair accuracy."
From the Forster page, on the net, on headspace gages.
FORSTER POST SAYS NOTHING ABOUT CASE HEADSPACE, AND AS SUCH DOES NOT SUPPORT YOUR DRIBBLE. DOWN TO 5 OF 7

"In practical terms, headspace is the clearance allowed between the base of the cartridge case and the face of the bolt."
From The Gunroom, a MSN site.
MSN SO CALLED QUOTE( WHAT REAL SOURCE ??) SAYS ABSOLUTLEY NOTHING TO SUPPORT THE CASE HEADSPACE DRIBBLE.
DOWN TO 4 OF 7

"When a cartridge having insufficient headspace is chambered, the action will be blocked from fully closing. Conversely, when a condition of excessive headspace exists, there will be some amount of linear “play” of the cartridge within the chamber when the action is closed. As a practical matter, some amount of headspace must be present to assure reliable operation and chambering. In most modern ammunition, this will be something on the order of four to six thousandths (.004" to .006") of an inch."
From www. exteriorballistics.com
WHILE THIS DOES TALK OF CART HEADSPACE, WHO POSTED IT, AND WHAT IS THIER AUTHORITY ?? A BALLISTICS COMPANY TALKING OUT OF THIER REALM OF EXPERTISE( SORTA LIKE JOE). PLEASE NOTE THAT A RIFLE WITH EXCESS HEADSAPCE IS TYPICALLY CONSIDERED UNSAFE BUT IN THE WORLD OF "CARTRIDGE HEADSAPCE" EXCESS IS GOOD ???
I'LL LEAVE IT AT 4 OF 7


"I have measured many, many types/manufacturers of commercial and NATO ammo via cartridge "headspace" gauges as well as "in rifle" checks."
Clint McKee at Fulton Armory site.
KNOWN IDIOT
4 OF 7

"When you use the Mic,your sized-case headspace needs to be about .001-in. less than what a normal, fired, new case has after it's been fired in your chamber."
Bart Bobbitt
UNKNOWN SOURCE
3 OF 7

See the armalite library headspace definitions.
NO QUOTE...YOU CANT CUT AND PASTE ANY MORE ??
2 OF 7

Measure cartridge headspace with a caliper? Absolutely! With this affordable gauge, it's as easy as measuring trim length. ...
www.stoneypoint.com/headspace_
ADVERTISING! A COMPANY THAT MAKES A TOOL THAT IS SOLD INDUSTRY WIDE AND IS A GREAT TOOL, BUT IT IS JUST ADVERTISING...THEY ARE NOT AN INDUSTRY STANDARD........YOU HONESTLY BELIEVE EVERYTHING YOU READ/HEAR IN ADVERTISING ??

SO WE HAVE JOE PROVIDING SUPPORT FOR HIS ERRORAND ONLY 1 OF SEVEN OF HIS POST ACTUALLY COME CLOSE TO SUPPORTING HIS CONTINUING ERROR.

WANT TO TRY AGAIN.......( A WOULD SUGGEST WHEN YOU MAKE YOU NEXT POST YOU READ WHAT YOU PUT UP HERE.....




There's much more if you want it.....YOU ARE KIDDING.... YOU ARE NOT EVEN CLOSE.
joe b.


JOE FIND SOME RECOGONIZED SOURCE IN THE INDUSTRY THAT USES THE TERM CARTRIDGE HEADSPACE!
HAVE YOU TAKEN THE TIME TO GO LOOK AT "THE" INDUSTRY STANDARD ?
GO LOOK AT A SAAMI DRAWING.....THERE IS NO HEADSPACE LISTED ON THE CARTRIDGE SECTION, ONLY ON THE CHAMBER DRAWING.

AND YES FOR THE RECORD, SINCE YOU PUBLISH FOR THE CBA, "YOU" ARE GIVING IT A BAD NAME.
NEXT
MIKE

[mike in co]

JOE AND ALL,
i went to the new cba site. it looks great, but unlike cast boolits, which is an open forum, cba is a closed forum, non members get no where....( i was doing as joe had asked and tried to look at his poorly labled chapter)

edit:

i was wrong, it said i was not allowed, if it had said i was not logged on, or go log on....i would have.
it would appear to be an open forum, but with joe being the moderator of his own book forums, thats pretty closed moderating.........
maybe i'll actually go post the SAAMI definition of HEADSPACE since he has left it open in his glossary.

[9.3X62AL]

This debate is starting to generate more heat than light. Illumination is far preferable to immolation.

[trk]

Joe -
I would hope that you'd go to a definative source for your definitions. In machine/mechanical design there is a language that provides the basis for communication between the customer, the design engineer and the machinist/tool-and-die makers. That language is drafting. THE basis for the terms is laid out in ASME/ANSI Standards (American Society of Mechanical Engineers and the American National Standards Institute). The Y14 series are the basis for all the terms, practaces and conventions.

From these lots of folks will deviate.

From these national standards, organizations as SAAMI produce their drawings, as noted in the title blocks as to the standard and the date of the standard; so that others will KNOW what the notations in the drawings mean.

It is important to note that in ANSI/ASME Y14.5M 1992 that one of the fundamental principles is that 'there will be ONLY ONE interpretation' of the drawing. (I'll look up the page and paragraph if needed.)

Let's start with something basic - the dimension. It is either a size or a location.

Next look at the term 'tolerance'. It refers to the allowable variation of a dimension. It's ok to be larger or smaller - within the allowable tolerance or range of size.

Thirdly the term 'clearance'. Clearance is the space between two things. It is affected by the tolerance of each of those two things. Large hole and small shaft give large clearance; small hole and large shaft give small clearance.

Headspace, I contend, is a space or clearance. It is affected by both the size inside the chamber and the amount of space that the cartridge takes up.

If the cartridge is the exact size of the cavity in which it is inserted, there is NO headspace.

If the cartridge is smaller than the cavity, there is some headspace - which can be measured by a headspace gauge.

If the cartridge is larger than the cavity the bolt won't close.

[mike in co]

joe,
please understand i'm picking on your choice of words( and yes a little on you for refusing to look at this with an open mind)....but only a little.
look at the stats for this board

Threads: 10,571, Posts: 116,947, Members: 2,205

i read almost everything posted here.
if anyone had used your term, i would have said something then.
you are the first to use this term with over 10,000 threads and 116,000 posts.....does that mean anything to you and your choice of words ??
no it is not "common" usage...except by one person....

you are writting for the public, use the common terms, if it is questionable use the standard of the industry...SAAMI.

mike

[mike in co]

This debate is starting to generate more heat than light. Illumination is far preferable to immolation.


al... i gave him a flash light( SAAMI STDS) , he is too busy collecting "data" to turn it on.

[mike in co]

See the armalite library headspace definitions.

There's much more if you want it.
joe b.


since joe point it out but chose not to post it, i went and read it...

here it is:
:TECHNICAL NOTE 60: MEASURING HEADSPACE

BACKGROUND: Measurement of a firearm’s headspace is a key technical inspection and has profound implications for the safety and durability of a firearm. The measurement technique itself is, oddly enough, so simple that it is frequently performed incorrectly. The purpose of this technical note is to provide facts and instructions for performing correct headspace checks.

FACTS:

1. Headspace is defined as minimum and maximum acceptable dimensions from the locked breech of a firearm to some point; either a contact surface or designated datum in the rifle chamber or to the rear of the barrel. Headspace ranges are established by industry advisory bodies, government bodies, or by individual manufacturers. The measurement points and dimensions chosen depend on the particular cartridge case used and its design (rimmed, rimless, semi-rimmed, or belted). In a narrow sense, headspace is the size of the cartridge chamber designed to accept a particular cartridge. In a broader sense, the characteristics of the firearm design must be considered when defining headspace.

2. A headspace gage is a precision-made device that measures the headspace of a firearm. It is normally cylindrical in shape, but depending on the design may resemble a washer or even a small plate. It’s key dimensions are based on industry standards or, more appropriately, industry standards that are adjusted to suit the characteristics of the firearm and ammunition being tested. These considerations guide the design of the headspace gage. ... "

TECHNICAL NOTE 11: HEADSPACE

BACKGROUND: Few topics inspire as much interest and confusion as headspace. It is one of the few technical small arms terms recognized, if not understood, by even beginning shooters. It is seldom firmly understood by even experienced shooters.

FACTS:

1. In a narrow sense, headspace is the size of the cartridge chamber designed to accept a particular cartridge. Headspace is defined as minimum and maximum dimensions from the locked breech to either a contact surface or designated datum in the rifle chamber, or to the rear of the barrel. The points of measurement chosen depend on the type of cartridge case used (rimmed, rimless, semi-rimmed, or belted).

2. In a broader sense, headspace is a far more complex relationship between the cartridge, chamber, and firearm mechanism. The starting point for headspace is the cartridge case. The complex functions of the cartridge case include holding the cartridge components together, aligning the bullet in the bore, expanding to seal high pressure gasses, contracting in time for easy extraction, and removing heat from the chamber. Proper space for the cartridge allows it to function well. Improper space can cause dangerous pressure conditions at worst, or interfere with the function of the action.

3. Headspace ranges are established by industry advisory bodies, government bodies, or by individual manufacturers. In the U.S. the primary advisory body is the Small Arms and Ammunition Manufacturers Institute (SAMMI). Issues of producibility, safety, and mechanism reliability with a particular cartridge must be considered. Firearm manufacturers must produce firearms with chamber headspace that is producible, yet assures safe and reliable operation with all ammunition made to standard. This becomes an extremely difficult challenge when making self-loading firearms.





while there is a discussion about the relationship between the cartridge and the chamber, there is no discussion of CARTRIDGE HEADSPACE, I see absolutely nothing supporting cartridge headspace....

mike

[trk]

It is interesting to note that (perhaps with the exception of CBA forums) that this is a typical reaction that Joeb gets.

It is a fundamental prinicple that one publishes and one's peers critique the quality of one's research published. He has done this on the CBA forum.

I could go on. But read it for yourself - for what it's worth.

[joeb33050]

I write the questions to a number of forums to get different ideas and to attempt to get others to tell me of their experience or maybe to experiment.
This infuriates some people, I don't know why.
I'm interested, here, about increasing clearance between the breech surface and the ctg head when firing slow loads in rimless/beltless ctgs.
I'm getting aggravation about the meaning of a word.
What I said is that I see three commonly used slightly different meanings for the word, and I wrote these definitions. This doesn't have much to do with the question at hand.
I still like my definitions, in my article I'm going to keep using them, and I'll only change them/it if convinced to do so-and I ain't convinced.
Words mean things to people, and these meanings change over time. I've cited use of the two definitions mike doesn't like, from Forster and Stoney Point, and somehow they're not acceptable.
I'm done with this discussion of the meaning of a word, if you object post your objection on the CBA site-I'll never moderate a dissenting opinion off the site.
trk-I don't understand your post, what are you saying?
joe brennan

[ssgt]

Gentlemen, whether we like it or not, SAAMI sets the specs and definitions for all this stuff and unless Ive missed something no one has posted that! So, a snippet from the horses mouth so to speak....

HEAD CLEARANCE
The distance between the head of a fully seated cartridge or shell and the face of the breech bolt when the action is in the closed position. Commonly confused with headspace.


HEAD, REBATED
See Cartridge, Rebated.


HEADSPACE
The distance from the face of the closed breech of a firearm to the surface in the chamber on which the cartridge case seats.


HEADSPACE GAGE
A device used in a firearm to determine the distance between the breech face and the chamber surface on which the cartridge seats. Also called Breeching Plug.


I checked , no mention of case headspace......


CASE GAGE
A fixture used to inspect cartridge case dimensions (i.e. length, diameters, thickness, etc.) to insure conformance to established tolerances.


CASE HEAD EXPANSION
An enlargement of the cartridge case head diameter on firing.


CASE HEAD SEPARATION
See Rupture.


CASE LENGTH
See Cartridge Case Length.


CASE LIFE
An expression of the number of times a case can be reloaded and fired.


CASE MOUTH



Nothing there.
SAAMI has spoken! :-D

[trk]

Joeb -

Let me be more blunt than what should be done in print, this should be face to face.



...
This infuriates some people, I don't know why.
...
I'm getting aggravation about the meaning of a word.

What I said is that I see three commonly used slightly different meanings for the word, and I wrote these definitions.
...
I still like my definitions, in my article I'm going to keep using them, and I'll only change them/it if convinced to do so-and I ain't convinced.

Words mean things to people, and these meanings change over time. I've cited use of the two definitions mike doesn't like, from Forster and Stoney Point, and somehow they're not acceptable.
...
trk-I don't understand your post, what are you saying?
joe brennan

Common useages of words come from common (less technically educated) use of the word that has a very clear meaning in it's technical origin.

You have chosen to use the less accurate definitions, broadening the meanings of the technical definitions.

You have chosen to ignore (except in one sentence above in your use of clearance) the definitions generated by the engineering and governmental organizations that the rest of the world uses.

You may choose to use your definitions - your choice. Your choice to use clearly defined terms and redefine them to have several meanings from several less well educated sources.

When you publish, as you have, which is good, your work for the world to see; the world notes your misconceptions and responds to them.

Your choosing to use the less accurate definitions of terms in a seemingly authoritive manner is an exercise in obscuring the understanding of the principles which you are researching.

If you choose not to start with the most authoritative source (which is not some verbage from someone's marketing department) you have lessened the technical accuracy of your own work.

Yes, terms' definitions change with time. Those definitions and their changes are clearly documented.

Go to your public library (at a college or university will be more fruitfull and you may have to get an inter-library loan to actually get it) and read the standards for yourself. Then YOU will understand the difference be the meanings of the clearance and tolerance.

What did my post mean? Your work is published. That it is published is good. It's quality can be recognized by all. It needs to be rewritten thoroughly using accurate definitions of the technical terms. THEN comes the very important question that you raise - the shortening or lengthening of the case dependant on the intensity of the charge.

It is an important question, there are many published observations of case length changing in both directions.

[ssgt]

I was wrong...Mike in Co posted this already....so I dont really understand the issue, Could be Im slow...

[trk]

...Mike in Co posted this already...


ssgt, Mike inCo -

Authoritative source (SAAMI) and clear definitions.

THANKS for posting these, THIS is the starting place.

In reading these, I will admit to learning the difference between HEADSPACE and HEAD CLEARANCE.



How about a link to the source?

[joeb33050]

First, I told a lie. If you put a post on a topic that's a book chapter, and I revise that chapter as I do daily, then I have to take the topic and ALL POSTS off before putting the revised chapter up. I don't delete your posts to be mean, but they will go away and you'll have to put them up.

I revised ON HEADSPACE, including the shoulder setting back article, no separate article any more. Please look this over and tell me what you think.

trk;
I ask for comments and editing and criticism, and it's because I recognize the shortfalls in what I've written. And I get editing and comments and criticism. Sometimes I change what I wrote, sometimes I don't agree with the commenter and I don't change it. I think that this means that the contributor and I disagree, many contributors think it means that I'm an idiot because I don't incorporate their stuff.

About words. I'm an Economist, and we define "an investment" as "an increase to the capital stock". Thus, we KNOW that when you buy a share of stock, you are not making an investment, you are merely exchanging pieces of paper. There's a technically correct definition, and a common usage. I'm not, none of the Economists are, going to try to "fix" this.

I'm continually begging people to write or edit or comment, and the response is light. I'm sure that you can write one or more of the chapters that we need. I'm sure that you could edit some of what's written. If you or anyone will volunteer, I can give you stuff to do in a hb.

As I wrote in the first edition, my original contributions to cast bullet knowledge are slim to none, I write what other people told me or wrote.

Check ON HEADSPACE.
joe brennan

[ssgt]

ssgt, Mike inCo -

Authoritative source (SAAMI) and clear definitions.

THANKS for posting these, THIS is the starting place.

In reading these, I will admit to learning the difference between HEADSPACE and HEAD CLEARANCE.



How about a link to the source?

Here ya go....

http://www.saami.org/Glossary/index.cfm

[ssgt]

joeb33050......
I understand what you are saying about the use of words however theres a BIG difference between a bad investment and a rifle chamber being over spec! Ive been on the receiving end of both and a bad investment, as uncomfortable as it is, is never as physically damaging as a rifle receiver going off like a grenade.

Whereas most of us may understand what you are saying, a beginner may not so accuracy in terms is of paramount importance if only from a liability standpoint.

[Maven]

joeb, For my own edification and perhaps peace of mind, let me try to summarize the thrust of your argument. Using the SAAMI definitions (above post):

(1) In some rifles, the blow of the firing pin alone can drive a case (cartridge) forward thereby altering both "case length" and "head clearance." Is this correct?

(2) In some rifles, the force of the primer's explosion (Is "explosion" the proper word?) can drive a case (cartridge) forward thereby altering both "case length" and "head clearance." Is this correct?

(3) Would it be correct to posit that in some rifles "case length" and "head cleanrance" may be altered by either the fall of the firing pin, the force of the primer's explosion, or both?

(4) Would it be correct to say that the ductility/hardness v. softness of the brass cartridge (by brand, for ex.) may also affect the amount of alteration in "case length" and "head clearance"?

Btw, I'm a sociologist and am all too familiar with trying to accurately define & measure concepts.

[trk]

Excellent, Mavin.

I would love to see experimental results on the effect of the 'brisance' of the primers on case length as well.

[hydraulic]

Are any of you guys sober?

[joeb33050]

joeb, For my own edification and perhaps peace of mind, let me try to summarize the thrust of your argument. Using the SAAMI definitions (above post):

(1) In some rifles, the blow of the firing pin alone can drive a case (cartridge) forward thereby altering both "case length" and "head clearance." Is this correct?
TOM GRAY MADE IT HAPPEN. I CAN'T, TRIED THREE TIMES. ANYONE CAN DO THIS TEST IN 20 MINUTES-I WANT MORE DATA! CAN YOU MAKE IT HAPPEN?
(2) In some rifles, the force of the primer's explosion (Is "explosion" the proper word?) can drive a case (cartridge) forward thereby altering both "case length" and "head clearance." Is this correct?
YES, I CAN MAKE IT HAPPEN IN 1 TRY.
(3) Would it be correct to posit that in some rifles "case length" and "head cleanrance" may be altered by either the fall of the firing pin, the force of the primer's explosion, or both?
IN MY GUNS, ONLY THE PRIMER. I HAVE ONLY TOM GRAY'S REPORT ON FIRING PIN VS MY 3 TRIES. NEED MORE EXPERIMENTERS.
(4) Would it be correct to say that the ductility/hardness v. softness of the brass cartridge (by brand, for ex.) may also affect the amount of alteration in "case length" and "head clearance"?
NO, ABSENT EVIDENCE. SHOW ME THE EVIDENCE. "MAY" BE ANYTHING.
Btw, I'm a sociologist and am all too familiar with trying to accurately define & measure concepts.

DRILLING FLASH HOLES #28 DRILL IS REPORTED TO FIX THE PROBLEM BY SEVERAL SHOOTERS. HENCE, I BELIEVE PRIMER CAUSE, ABSENT ANY MORE EVIDENCE. I DON'T UNDERSTAND THE RELUCTANCE OF MEMBERS TO EXPERIMENT. NEEDED IS A RIFLE WITH A REMOVABLE FIRING PIN ASSEMBLY, AND SOME PAPER FOR SHIMS AND A FIRED CTG CASE. OPINIONS ABOUND, EXPERIMENTS ARE THIN ON THE GROUND.
joe brennan

[joeb33050]

In the article but I forgot to put it here. Some report that leaving sizing lube on the case keeps the shoulder from moving back.
Did anybody read ON HEADSPACE? Anybody want me to put the new chapter here?
joe brennan

[trk]

Yup. I read it. Better. Would be an excellent opportunity to add HEAD CLEARANCE definition. (it may have changed since I read it)

It's easy enough to get to there, thanks.

[trk]

Are any of you guys sober?

Yes, but that can be fixed. :)

[Maven]

All, Tom Gray's article, ".308 VS (sic) .30-30" in "The Fouling Shot" #184 (pp. 12-13) essentially confirms some of what Joe has found. Let me briefly quote from the article:

Re a rimless case (.308Win.) & low pressure (20-30k psi) CB loads "...even worse, when the firing pin hits the primer, it drives the case forward and sets the shoulder back. This causes excess headspace to develop over time. There is not usually enough pressure to expand the case to fit the chamber again and re-headspace (sic) the case." (p. 12, para. 5)

In the next paragraph, Tom defines "headspace" and describes how he measured changes in it.

[trk]

Joeb - Let me toss out a question for the sake of scientific investigation. Assuming that pressure increases with the charge, and that at some point of increasing the charges the case will seal better than with lesser charges, is that point coincident with the shrinking vs. case expanding? Now the question, assuming that the first is generally true, how is accuracy affected? (That is to say, is this a major or a minor contributor to the size of the group compared to the contribution of say vibration of the barrel?)

[Maven]

joeb, Re the 4th point (brass ductility) in my earlier post, how can you state so categorically ("NO") it has no effect when you have, by your own admission, no evidence in either direction? Also, materials testing isn't exactly my line of work so please tell me how one would establish with reasonable certainty that different brands of brass either may or may not vary in ductility/softness? One additional question: Other than "getting it right" for your book, what practical difference does this altered cartridge length/"headspace" make? Is it dangerous? Does it lead to misfires and if so, is the relationship predictable such that the shorter the cartridge becomes, misfires will become more frequent?

[mike in co]

INCREASING HEADSPACE-SLOW LOADS It is often said that shooting cast bullets slow in not-rimmed-or-belted cases increases headspace.
joe b.

I THINK I'M GONNA TRY ONE LAST TIME.

JOE,
you start with a poorly worded opening statement"INCREASING HEADSPACE-SLOW LOADS"
now we have discussed this to death, but it sucks. more appropriate terminology would ADD to your publishing. as it is , it SUBTRACTS from what is to follow. its your name, your article. i would thing you would like something to be proud of, not something that would be questioned just in its lack of technical language.

NEXT joe states
"It is often said that shooting cast bullets ...."
SORRY JOE but you fail in your premise....you set yourself up poorly again.
joe , if it was "often said" i think we would have more data, but the fact is, it isnt "often said", hell it aint even "Ocassionaly said", its more let it is "rarely said".
so now we have a poor title, a poor premise, and then
well next we have JOE'S Tests
lets back up a bit... the premise said:
" that shooting cast bullets slow in not-rimmed-or-belted cases increases...."

now lets look again at joes "tests"
firing primers in empty cases and hitting cases with a firing pin

would someone tell me which of the two tests above fall into
" that shooting cast bullets slow in not-rimmed-or-belted cases...." ????

niether has anything to do with a loaded case being fired in a chamber.
the tests DO NOT PROVIDE DATA THAT SUPPORTS THE PREMISE!

now i'm not a scientist, but if you want some DATA on case SHRINKAGE/SHORTENING in slow cast boolit loads, i'd go get me a stoneypoint case measuring tool, some cast boolits and start creating some data, by measuring loaded cases, firing them and looking at the change. of course it would be nice to have some control DATA to compare to.....like some full house cast boolit loads, some control lots of brass in two lots( slow and full power).... fire everything a giving number of times, measure every case every time, record your findings. now if cases do not shorten, try a new load and start over. but to publish only the results that generate a short case, and not acknowledge that not all tests resulted in shorter cases is poor writting at the least, and fraud on the shooting public.
i have not read your chapter today, but earlier it only had data that supported what you were trying to say, and no reference to any other contrary data.

i really believe you need to go back and start over, because what you have to day is not proof, it is just dribble.

mike

[mike in co]

I ...
I've cited use of the two definitions mike doesn't like, from Forster and Stoney Point, and somehow they're not acceptable.
I'm done with this discussion of the meaning of a word, if you object post your objection on the CBA site-I'll never moderate a dissenting opinion off the site.
trk-I don't understand your post, what are you saying?
joe brennan


joe,
stoneypoint is advertising...most of us, recognize the liberties taken in the advertising world. stoney point is not writting articles about case shrinkage in cast boolit loads, though thier tool would be of great use to one investigating the premise.
show me where forsters headspace tools speak of cartridge headspace ???
nowhere period. hell i like forsters definition...it aint yours!

again show us someone in the industry( that would be a company that deals with case size/sizing/chamber design) that uses YOUR defintion of cartridge headsapce.

[joeb33050]

Joeb - Let me toss out a question for the sake of scientific investigation. Assuming that pressure increases with the charge, and that at some point of increasing the charges the case will seal better than with lesser charges, is that point coincident with the shrinking vs. case expanding? Now the question, assuming that the first is generally true, how is accuracy affected? (That is to say, is this a major or a minor contributor to the size of the group compared to the contribution of say vibration of the barrel?)

I don't know. To any of the questions.
joe brennan

[joeb33050]

joeb, Re the 4th point (brass ductility) in my earlier post, how can you state so categorically ("NO") it has no effect when you have, by your own admission, no evidence in either direction?
Paul, the -your-question begins:"Would it be correct to say..."
My answer is "No, absent evidence" It's not correct to say... I'm answering the question.
The number of hypothetical contributors is legion, the only cause I've found is the primer driving the case forward increasing headspace.

Also, materials testing isn't exactly my line of work so please tell me how one would establish with reasonable certainty that different brands of brass either may or may not vary in ductility/softness?
If I wanted to know and was limited to what I own = no lab; then I'd shoot cases with full loads, clean the inside of the necks, and measure, maybe a fish scale, the force required to size them.
Or, size them, then measure the force required to push an "M" die into the neck.
There are other tests. N.B. Softness and ductility are different.

One additional question: Other than "getting it right" for your book, what practical difference does this altered cartridge length/"headspace" make?

The increased headspace can lead to not firing= misfires. Does lead to primers protruding.

Is it dangerous?
With light loads, probably not. BUT, if ctg cases with excess headspace = too short are then loaded with full charges, then it is possible that the case can seperate = trouble.

Does it lead to misfires
It can, but see above.

and if so, is the relationship predictable such that the shorter the cartridge becomes, misfires will become more frequent?
Somewhere between probably and maybe, but see C. Dell's work on primers in the book

Summary: It appears that the solution is enlarging flash holes and segregating these cases. Or, leaving sizing lube on cases.




It wants me to write something here.
joe brennan

[joeb33050]

I THINK I'M GONNA TRY ONE LAST TIME.

JOE,
you start with a poorly worded opening statement"INCREASING HEADSPACE-SLOW LOADS"
now we have discussed this to death, but it sucks. more appropriate terminology would ADD to your publishing. as it is , it SUBTRACTS from what is to follow. its your name, your article. i would thing you would like something to be proud of, not something that would be questioned just in its lack of technical language.

NEXT joe states
"It is often said that shooting cast bullets ...."
SORRY JOE but you fail in your premise....you set yourself up poorly again.
joe , if it was "often said" i think we would have more data, but the fact is, it isnt "often said", hell it aint even "Ocassionaly said", its more let it is "rarely said".
so now we have a poor title, a poor premise, and then
well next we have JOE'S Tests
lets back up a bit... the premise said:
" that shooting cast bullets slow in not-rimmed-or-belted cases increases...."

now lets look again at joes "tests"
firing primers in empty cases and hitting cases with a firing pin

would someone tell me which of the two tests above fall into
" that shooting cast bullets slow in not-rimmed-or-belted cases...." ????

niether has anything to do with a loaded case being fired in a chamber.
the tests DO NOT PROVIDE DATA THAT SUPPORTS THE PREMISE!

now i'm not a scientist, but if you want some DATA on case SHRINKAGE/SHORTENING in slow cast boolit loads, i'd go get me a stoneypoint case measuring tool, some cast boolits and start creating some data, by measuring loaded cases, firing them and looking at the change. of course it would be nice to have some control DATA to compare to.....like some full house cast boolit loads, some control lots of brass in two lots( slow and full power).... fire everything a giving number of times, measure every case every time, record your findings. now if cases do not shorten, try a new load and start over. but to publish only the results that generate a short case, and not acknowledge that not all tests resulted in shorter cases is poor writting at the least, and fraud on the shooting public.
i have not read your chapter today, but earlier it only had data that supported what you were trying to say, and no reference to any other contrary data.

i really believe you need to go back and start over, because what you have to day is not proof, it is just dribble.

mike

I think you mean, it is just drivel.
joe brennan

[mike in co]

ok guys , i stirred the pot one last time. we are gonna see what kind of a man joe is.
i took several of my posts and put them on the cba site.
i started a new thread asking for a vote on headspace definition.
now joe is a moderator on the site....lets see if the post reamin and what happens.

[trk]

ok guys , i stirred the pot one last time. we are gonna see what kind of a man joe is.
i took several of my posts and put them on the cba site.
i started a new thread asking for a vote on headspace definition.
now joe is a moderator on the site....lets see if the post reamin and what happens.


I noticed another moderator's comments about accuracy of terms on CBA.

I sent Joe a PM (on CBA's site) in reference to another issue of great importance - as you say we'll (I'll) see if he considers it.

[milkman-06]

Gentlemen,
This topic has brightened the light bulb above my head. Thank you all very much.
Russ Neely
milkman-06

[mike in co]

LADIES AND GENTLEMEN,
while i may not agree with everything joe has said, it is nice to note that he has revised the title of his chapter to a more universally recognized wording. i do not know what finally changed his mind, but I BELIEVE that some of what he had posted was not only wrong but unsafe.
so joe, thanks for seeing the light.
good luck with your book.
mike

[carpetman]

Mike In Co---If using the wrong terminology makes an unsafe condition,I'd say Veral Smiths Book(well ok is it a book or a pamphlet)has my vote for the most dangerous work ever.

[joeb33050]

Mike In Co---If using the wrong terminology makes an unsafe condition,I'd say Veral Smiths Book(well ok is it a book or a pamphlet)has my vote for the most dangerous work ever.

Who is that girl in the picture? What is her name? Do you have her phone number? Does she date mature men = 68? Help me on this!
joe brennan

[mike in co]

I'M REPOSTING THIS(ITS NOW ON HERE THREE TIMES, BUT JOE SEEMS TO MISS IT...ALOT!)
FROM SAAMI GLOSSARY:

HEAD CLEARANCE
The distance between the head of a fully seated cartridge or shell and the face of the breech bolt when the action is in the closed position. Commonly confused with headspace.


MAYBE WE CAN GET SOMEONE TO READ IT TO HIM ???

[45 2.1]

The Cast Bullet Assoc. Forum closed the topic on this subject. I wonder about what the final outcome of this topic will be and will wait to see if any credibility is reestablished.

[Pat I.]

I wonder about what the final outcome of this topic will be and will wait to see if any credibility is reestablished.

Not quite sure I understand this comment??

Pat

[Char-Gar]

When I took a wildlife biology course in college about 1962, I found out the difference between a rabbit and a hare. I also found out that the famous Texas Jackrabbit was indeed a hare.

For many years, I tried in vain to straighten folks out and call the long eared critter a Jackhare as is correct.

I think of this when I read all of this stuff about calling cartridge headspace "head clearance" because some science text says that is correct.

Joe has been castigated for using common and understandable language instead of a correct technical term that most folks don't understand.

I have been shooting and reloading for 47 years without reading the SAMI (or whatever) glossary and see no reason to start now.

So....get it right...they are Jackhares!!!!! Oh yes.. The time spent reading the SAMI stuff would be better spent with the Bible or at least Elmer Keith.

[mike in co]

...

Joe has been castigated for using common and understandable language instead of a correct technical term that most folks don't understand.

I have been shooting and reloading for 47 years without reading the SAMI (or whatever) glossary and see no reason to start now.

....
CHARGAR,
THE ISSUE I HAVE IS THAT WITH OVER 10,000 THREADS ON THIS FORUM, AND OVER 100,000 REPLIES, IS THAT joes post was the first post using this terminology. it was the first time i had heard or seen it in print.....and joe changed his presentation three times from when i first objected. sorry but i do not and did not see it as "common" use. in the end i did understand what he was trying to say. i also dissagree with your statement that "most folks don't understand" SAAMI'S definition of headsapce and head clearance. maybe its a difference in background( mine is nuclear, areospace, and weapons testing), but i see the definitions as pretty simple english.

mike

[Steelshooter]

I think you posted your job history 10,000 times. I think everybody gets it, let it go and think of the upcoming holidays. Merry Christmas to everybody!!!!!!
Chuck

[carpetman]

Mike In Co---Maybe I found the problem. Chargar made a post and you responded to Charger. Pay attention to detail---look on members list--we have a Charger and a Chargar. Nuclear,aerospace ,and weapons might not be so critical and you could get by with that kind of slop but here it will get noticed.

[carpetman]

Chargar---Is a cottontail a rabbit or a hare? I need to know this. Might make some rabbit stew and wouldn't want folks finding a hare in it.

[robertbank]

If it lives underground it is a rabbit otherwise it is a hare. Or is it the otherway around? Ummm hairy question no doubt but I think I got it right the first time.

Take Care

Bob

[waksupi]

Geez, I got out of aero space thirty years ago. Think I still have the union card around somewhere. And not only do I test weapons, I build them for a living. Life is good

[klausg]

Bob-
IIRC, and help me out here Chargar, it has to do with how the young are born. Hare are born pretty much ready to go, eyes open, etc., whereas rabbits are born w/eyes closed.

-Klaus

[mike in co]

Mike In Co---Maybe I found the problem. Chargar made a post and you responded to Charger. Pay attention to detail---look on members list--we have a Charger and a Chargar. Nuclear,aerospace ,and weapons might not be so critical and you could get by with that kind of slop but here it will get noticed.

yep i agree, noted and corrected...

mike

[robertbank]

God you have to love this forum! Here are the differences from the net:
"
The difference between rabbits and hares appears at the moment they are born. First of all baby-rabbits are called kittens, while baby-hares are called leverets. Rabbits are born completely helpless, naked and blind. Hares are born fully furred, able to see and capable of independent movement. In fact hares can live on their own after one hour from they birth! Therefore their mothers feel free to leave them on the bare ground and hop away soon after the baby is born. Rabbit's mothers are much more careful and protective to their children: their line a nest with grass, bark and soft stems. Over this, they place a layer of hair plucked from their own bodies. When rabbit-mother leaves the nest, she covers the bunnies with more hair and dead plants to keep them warm and hidden from enemies.
Hares are generally larger, and have longer hind legs then rabbits and longer ears with characteristic black markings. The skulls of rabbits and hares are also different. Rabbit's fur coat remains its color year-round, while hares change color from grayish brown in summer to white in winter.
Rabbits and hares have different diets. If rabbits prefer soft stems, grass or vegetables, hares eat more hard food: bark and rind, buds, small twigs and shoot.
Rabbits usually live in burrows or tunnels in the ground, where they prefer to stay during daylight hours. They try to keep hidden. Hares on the other hand, always stay on the surface among plants and usually try to escape enemies by running.
Rabbits are very social animals; they live in colonies. Male rabbits even fight within a group to become the dominant male. The dominant male rabbit then mates with most of the females in the area. In opposite, hares live most of the time by themselves. They come together in pairs for mating only. There is almost no fighting among hares - they just pair off.
It is amazing that the nature has created such different animals to look the same. But now we know the difference between them and will not be deceived anymore by those tricky long-eared creatures.

Well I had one difference.

Take Care

Bob

[leftiye]

This must be page 96 of that thread I got tired of last week. Gee I'm glad that I couldn't find it again!

[robertbank]

Never a dull moment in the exciting lives of bullet casters.

Take Care

Bob

[flinter]

Wonder what would happen if you tried some cases with no flash hole?
I got some Win cases that way with no hole atall but they are rimmed.
You could prolly figure a way to do it but would it be safe? Primer compound is high explosive and like any other H.E. dont take well to being confined. So I guess in this case the whole brass case becomes the piston, yes?
BIC/BS Hi, I was on the range shooting in a match, and had what seemed to be a misfire ( there was no explosion) ..
when the shell was extracted it was obvious that the primer had gone off because the projectile had been forced into the rifling as well a good portion of the case about 3/16 of an inch..
a quick look showed that there was no flash hole , this was on new .308 ammo from a recognized supplier ..
So in that case I figure that with no load , in some cases , firing a live primer only could push an empty case forward and so shorten it some ..Flinter

[walltube]

Bob, thank you for the rabbit vs hare lesson.

Anybody out there know if hare krishna are pliestocene?

In frenzied anticipation,
Wt.