How to bump back the shoulder

[hounddawg]

A case being sized down in diameter by a FL sizing die is supported,at least on the outside.

Aside from some silly word puzzle argument,if a case is checked in an RCBS Precission Mic or a bushing type "Case headspace gauge" as the manufacturer calls them....
If this case shows the "case headspace" is .004 out of spec,long,

And if I run it through the FL sizer die and it comes into spec,the case head to shoulder datum length has been reduced.

That's the desired result,Mr Guffey.All the rest of the reloaders(except you) call that bumping or setting the shoulder back.

Apparently you are the "Only Reloader" who cannot perform the shoulder adjustment that the rest of the reloaders have been doing since FL sizing dies have been produced

well said HiBC

[Unclenick]

Don't forget to trim after using the FL die. That's when cases grow.

You may want to experiment with turning the die back out so that your shoulder gets extruded down only about -0.001" to -0.002" shorter than your chamber headspace. That is what Mr. Guffey is doing with that 0.003" feeler gauge. That will reduce how much it stretches at the pressure ring during your first firing after a trip through the FL sizing die. In turn, that will increase the number of times you can fire it before pressure ring thinning becomes an issue. If you also anneal them just before you use the FL die and you are not using heavy loads, you may discover you can get 50 reloads out of the cases.


HiBC,

The RCBS Precision Mic is designed to determine chamber headspace by transfer measurement. It is premised on the idea the case will expand to fill the chamber on firing and therefore come out fireformed to mirror the chamber's size. When you put the fireformed case in the PM, it then reads the chamber's headspace by measuring the case (aka, taking the chamber measurement off the case). From RCBS's web site:

{The RCBS Precision Mic:}
• Determines chamber headspace and bullet seating depth to 0.001-inch
• Measures from the datum point on the caseshoulder to the base, giving reloaders spot-on SAAMI tolerance readings

In other words, it measures chamber headspace by taking it off the case or it measures whether the case head-to-shoulder length meets SAAMI spec or not, but nowhere does it claim to measure "case headspace". There is none as no case head has to go inside the case, and accommodating a case head is what headspace is for.

I promised I would put up a sticky for headspace so all such disputes could go there. I have the drawings ready and soon will put it up.

[HiBC]

Unclenick, I know the term "Cartridge Headspace" is technically incorrect.
I understand from chambering rifles that only the firearm has "headspace"

As folks try to learn about the reloading issues...over and over and over again,we have to use words to describe concepts.
"For lack of a better term"

Usually we are talking about how the reloader deals with the case head to shoulder datum length as it relates to his or her individual or multiple rifle chambers both before and after firing and how die settings may be used to correct or optimize the brass to chamber relationship.

I don't want to type all that every time.

At least one of the bushing gauge manufacturers calls the gauge a "Cartridge Headspace Gauge"

If I say " M-1 Carbine 30 round banana clip" everyone will cringe,I'll get criticized,but you will be able to see and understand what I'm taking about.

I have an easy,readily available,understandable term to use instead.,"30 round carbine magazine"

I use it. I don't use "Clip" except for en blocs and strippers.

Please,Unclenick,

I'm tired of this. I'd be grateful if you can offer a simple,three word term that we can use instead of "Cartridge Head Space" Even four or five words.

For "my bolt won't close" or "I'm getting head separations" etc.

And,FWIW,I have no doubt you are accurate and correct about RCBS and using the PM to measure chamber length.
I learned of the PM from Precision Shooting Magazine's book "Guide for reloading competition ammunition" or something like that.
They suggested using the PM to make a before and after sizing measurement of the cartridge case so we can optimize setback for brass life and rifle type...for example an M-1 might work better with .006 and a 1903 .002.

That is where I learned about the RCBS PM. I found the bushing gauge and ,if needed,the granite comparator stand with indicator to compliment the bushing gauge both cheaper and more efficient.

The various caliper and bushing setups work fine.

If I say "That's how I check cartridge headspace",you may cringe,you may roll your eyes,you may criticize and correct me,but we communicated and you know what I'm talking about.

For lack of a better term.

This link will get you to Sinclair (Brownells) Reasonably tech folks

https://www.sinclairintl.com/reloadi...ools/index.htm

The Hornady bushing set and the RCBS PM are listed as "Cartridge length headspace" tools.There is a Wilson bushing shown, Click on it The description is "Cartridge length headspace gauge"

I agree,headspace is about the breech and chamber.That is the PARENT. but the cartridge case becomes a CHILD of that chamber,.Critical aspects of reloading and resizing are all about the parent headspace of that chamber.
Upon firing,those headspace measurements transfer to the brass.
We size to restore the brass dimensions to fit the rifle headspace.

IMO,we just make life difficult if the word "headspace" is taboo from cartridges unless there is another acceptable term.

[cw308]

RedSkyFarm
If your fired cases can't chamber , you can use the full length die and slowly lower each time with checking in your chamber until it chambers without resistance that would be your zero headspace measurement , it's best to do with a stripped bolt using only the housing for a better feel . Good Luck , glad everything worked out . Be Well .
PS
For hunting you may be better with .003 from bolt face to datum . I use my rifle for benchrest shooting only , only in good weather conditions so I keep my measurement from .001 to .002 no more or !ess . Hard bolt lifts will eventually wear on your bolt locking lugs and you don't want that .

Chris

[Unclenick]

Originally Posted by HiBC

I'd be grateful if you can offer a simple, three word term that we can use instead of "Cartridge Head Space" Even four or five words.

I appreciate that the correct terminology doesn't trip lightly off the tongue. I actually asked for suggestions for a new term in a past thread, but don't recall the outcome. Unfortunately, that means it wasn't memorable enough to take.

One of the members commented that he avoids having to find a term by discussing only Excess Headspace. That is extra room a chamber's headspace has for a cartridge. When the case head-to-headspace-datum measurement matches the headspace the excess headspace is zero. If it's too big, excess headspace gets a negative number, and if it is shorter than the chamber headspace then excess headspace gets a positive number.

Let's put out the call again for a better term that uses no more than three words. I've yet to find anything satisfactory on my own.

[cw308]

I still like headspace . Everyone knows what I mean . Just like tomato , potatoe , aunt and my favorite ask . I guess , to each his own and pray for the best . Making a mountain out of a mole hill . No Big Deal .Be Well Guys .

Chris
PS How about wiggle room . Sounds Precise .

[HiBC]

One of the members commented that he avoids having to find a term by discussing only Excess Headspace. That is extra room a chamber's headspace has for a cartridge. When the case head-to-headspace-datum measurement matches the headspace the excess headspace is zero. If it's too big, excess headspace gets a negative number, and if it is shorter than the chamber headspace then excess headspace gets a positive number.

OK. I chamber a rifle with headspace gauges. It just accepts the "GO" It won't accept the "No Go".

Nothing else is headspace and the headspace is perfect.

Cartridge case head to datum measurement is wrong.Ammo is wrong. Nothing needs to be done to the rifle.

How do we talk about it without using the word "Headspace" and correctly attribute it to the ammunition and discuss reloading techniques.

I value plain speaking over the contortions of political correctness.

Unclenick,I value and appreciate your answer. Thank you for recognizing my point.

In the mean time,until there is a consensus term that does not require a 3 paragraph explanation,I'm going to use "cartridge headspace" in quotes.

The quotes are a sign I do not need the argument "Cartridges don't have headspace"

If you ask me about cartridge length,I assume LOA I can give a number.

If you ask me about case length,I assume trim length.I can give a number.

If you ask me about cartridge headspace,I know what you mean,but I can't readily give you a meaningful number.What I measure is a comparative number."Fired brass was 2.XXX,and after sizing its 2.XXX (-.003). The .003 is the number I want and can measure. Head clearance.


My bushing gauge may tell me brass is ,004 over max SAAMI. That's a useful number.I suppose we could call it "Head interference"It can tell me its within SAAMI,High limit SAAMI,or .003 shorter than High SAAMI. I can establish that my 1903 has .002 Head clearance when its .003 shorter than bushing Gauge High SAAMI limit


Then there is the Basic Dimension,Maximum Material Condition,Minimum Material Condition,etc.If you don't have to allow for positional tolerance,

One approach ,two parts at basic dimension will be a line to line fit at Maximum material condition. But we are looking for simple,common language.

What I can talk about and measure,what is meaningful,and the point,is "Head Clearance" which is even technically accurate.

But to explain head clearance,I have to reference the "Cartridge Headspace" concept.

[cw308]

At one time I had no idea what runout was , even with runout and where you measure from makes a difference but even though you know what I'm talking about . When working in thousandths you have to be pretty technical . That's coming from a guy , if it wasn't for sports I would still be in high school. I still like " headspace " sorry .

[USSR]

Since the condition of excessive headspace and insufficient headspace in a rifle can be induced by the amount a shoulder is or is not bumped back, case headspace is a fitting term and one for which I will gladly suffer the slings and arrows of terminology purists on this site. Sorry.

Don

[Unclenick]

The reason for avoiding it is to prevent confusing newbies who may not at all know what you are talking about. I don't want to be asked, "how do I use this GO headspace gauge I bought to measure my cases?"

Anyway, I don't have a good terminology alternative to a full description. I thought of 'shoulder length' and 'datum length', but those only apply to cases that stop on their shoulders in the context of fitting into an allotted headspace. 'Case Headspace Fit' would seem to take the onus off the reader to realize headspace is not a characteristic of the case.

But maybe this is overthinking. Why not just say you are setting excess headspace instead of setting case headspace? The terms are all correct and excess headspace is, indeed, controlled by the sizing of rimless bottleneck cases and by trimming cases that stop on their mouths. There is no way to set it in a rimmed or a belted case, though you can sure set the head-to-shoulder datum length on either one and even change the surface that sets the headspace to the shoulder from the rim or belt.

Anyway, I'll ask you both to jot down any ideas that come to mind and post them in the headspace sticky I am creating.

[hounddawg]

I don't want to be asked, "how do I use this GO headspace gauge I bought to measure my cases?"

if the person asking has used that gage to set the headspace on a rifle using a barrel nut tell them to use a case comparitor like this

https://www.amazon.com/Hornady-HK66-...p_89%3AHornady

and when setting up their resizing die to where the cases coming off the press match the reading they get using the comparitor against the GO gage. When they are equal the FL die is set correctly. DO NOT try this on a factory barreled rifle or a used rifle unless you have tried chambering both the GO and a NO Go gage to make sure the rifle was set up correctly

I have a pair of .260's I set up exactly the same way so I don't have to worry about sorting cases. As a test I chambered a case fired from each into the other and had no signs of bolt closing pressure with either rifle

[Metal god]

I appreciate that the correct terminology doesn't trip lightly off the tongue. I actually asked for suggestions for a new term in a past thread, but don't recall the outcome. Unfortunately, that means it wasn't memorable enough to take.

It was head clearance or casehead clearance , I liked head clearance but Slamfire preferred casehead clearance . But asking for everyone to make up a new term different then the one we ALLLL have excepted except one person and now you UN is NOT reasonable . Just like I have to except the word hack can be used in a way to mean something good . I don't like it , it was never used in that way for 45+ years of my life . Then the internet came along and people came up with new terms and the group excepted them . Hack ( doing something in a quick manner in a beneficial way ) and case headspace ( the distance from the case head to the datum point on a bottle neck case ) is but a few new terms the world has excepted as reasonable . The ignorance it takes to think he is the only one on the planet that gets to decide how others talk to one another or what words they use , is absurd .

Just because he wants to be old a stubborn doesn't mean the world is going to stop evolving .

The reason for avoiding it is to prevent confusing newbies who may not at all know what you are talking about.

There is only one person , well I guess two now that are confusing the new guys . That's the guys fighting every single time the term case headspace is used . Maybe if you two excepted what the industry and 99% of the reloaders have excepted as a new term . We could all move on .

If you'd like I'm more then willing to find every post a certain member has posted on this subject not only here but 5 other forums and the hundreds if not thousands of responses explaining in great detail how they disagree with him and he has been the only one defending his position on the subject .

Or Unclenick are you formally asking us all here at TFL to stop using the term case headspace and bump the shoulder back . Because if your not then you need to ask Mr Guffey to stop derailing threads every time those terms come up .

We've been going trough this for the 6 years I've been here EVERY time this topic comes up . I'd like you to either ask us all to stop using the terms that Hornady , RCBS and Berger have all excepted as reasonable to use or to ask Mr Guffey to stop arguing about those excepted terms with the members here .

Respectfully
Metal God

[hounddawg]

Great minds discuss ideas; average minds discuss events; small minds discuss people. Idiots argue semantics - apologies to Elanor Roosevelt

Might just be me but I am tired of the trolling on this forum on this forum. There are a lot of good people here trying to help the community and one or two who just want to pump up their tired ass egos and troll. If I go to the range and discuss cartridge headspace any reloader there knows what I am saying, I could give a s*** about the semantics as long as the communication takes place

just my 2 cents worth

[F. Guffey]

Reloaders were claiming they were bumping the shoulder back with a bump die; if there was such a die I am sure I had one but I had no clue what it looked like. So? That left me with asking questions. As everyone should expect that ran them out of gas and they got hostile.

I did a little search and found the manufacturer of the die the reloaders were calling a 'bump die'; I called them about their bump die and I wanted to know how to bump the shoulder back? with a die that did not have case body support. BECAUSE! reloaders on the internet were claiming they were bumping the shoulder back ONLY.

They responded: They said I knew and they knew it was impossible, the die reloaders were claiming to be a bump die was a bushing die and manufacturer made it very clear the bushing die was a sizing die that sized the shoulder and case body.

And then I reflected; I went to my library to retrieve the book on vanity; life is vanity all vanity. I thumbed through the book to a worn pace and there it was:

"It is greater to receive the wrath of a wise man than the rhetoric of a fool"

F. Guffey

[F. Guffey]

I could not understand why reloaders got all giggly bout bushing die. I have neve had to purchase one because I already had them. And then there was the problem with 'the donut'. I have chambers/cases that will never form a donut, I have chambers that are by design to create donuts and there are donuts that form because of bad habits.

F. Guffey

[cw308]

F.Guffey
So what's happening when sizing for that proper length , I didn't say headspace . The body is being formed and reformed the shoulder is remaining unchanged . I can see that , would you agree or am I missing something ?

Chris

[Metal god]

My dad once told me ( at the time I did not like hearing it ) If you have a problem with everybody , It's not everybody that has the problem !

[F. Guffey]

So what's happening when sizing for that proper length , I didn't say headspace . The body is being formed and reformed the shoulder is remaining unchanged . I can see that , would you agree or am I missing something ?

I suggested scribing a line around the case at the case body/shoulder juncture. The scribed line will become an artifact; I have formed 30/06 blanks into 8MM57 cases, when forming I could not get rid of the artifacts from the 30/06 blank cases. It means nothing to anyone on this forum but there was a reloader on ebay selling 8mm57 cases that were formed from 30/06 blanks.

Missing something? Yes; I insist it is impossible to move the shoulder back with a die that has no case body support because without case body support the case will collapse.

How much will the case collapse? I have formed bellows below the shoulder to the point the case took on the appearance of an accordion. And there is another tie-in; The seating die does not have case body support, if the reloader applies too much crimp the case will start to bulge at the case body/shoulder juncture.

And then there is the bully factor, many reloadrs on the Internet insist other reloaders agree with them. Those are the ones I can not get them to remove their hands from the keyboard when it comes to scribing lines etc.

Missing something else; when reloaders do their memory work they insist the firing pin hits the primer and drives the case, powder and bullet to the front of the chamber before the primer is busted. At one time I asked a lot of questions of the shooter/reloader that made up that cute little saying. He never responded; finally I asked him if he ever considered if there was a remote chance he could have left out a few sequences or if there was a chance there were other possibilities. After that I had to assume no one knew or they did not afford themselves the luxury of disagreeing.

And then there are those that "get so confused" like the time I chambered 8mm57 ammo in one of my 8mm/06 chambers. I pulled the trigger; if there was any truth to the cute little saying I should have experienced case head separation because the difference on length of my chamber from the shoulder to the bolt face and shoulder of the case to the case head was .127". According to the cute saying I should have had case head separation, instead I ejected a case with a long case body and a very short neck.

"So confused?" Had the case shoulder been driven forward and made contact with the shoulder of the chamber the length of the neck would not haver changed when the round was fired. The fact the neck shortened proved the shoulder did not move (by much); 'missing something' the shoulder of the 8mm57 did not move, the shoulder behind the short neck was a new shoulder.

F. Guffey

[Metal god]

I'd like to apologize to the OP RedSkyFarm for being apart of this derailment but you are just the latest of many victims of a single member here .

[cw308]

That taught me a lesson . A cute little saying ? I'm all ears . Sorry.

[Don Fischer]

Bump the shoulder is a bad word. You just bump it and the case still won't load in the rifle. You have to move the shoulder, just move the shoulder enough to let the round chamber. You can move it enough that you'll still be able to feel it when you close the bolt and that will work. I move it enough so I don't feel the rub any more.

How to do it? Easy. Losen the lock ring on the FL die and move it back just a bit. Now screw the die all the way down till it touch's the shell holder. Next, back the die out a couple turns, the shoulder should not touch then. Tighten down the lock ring just finger tight and lube and run a case into the die. Take that case and put it in your rifle and try to close the bolt, it should not close. Next losen the lock ring again and turn it down about a quarter turn and re tighten the lock ring. Run the case in again and then try it in the gun. Keep doing that till the case goes in smoothly. If you want to feel it rub, your call. I like then to go in smoothly. Once you get it there, tighten the lock ring well and lock it right there. Dedicate it to than rifle and you'll never have to neck size again, you'll be FL sizing the case's to fit that chamber. Called partial sizing. I've recently started trying a collet die to neck size my 243. Don't know yet how long it will take to have to FL resize or even it I'll have to, haven't done enough yet. Advantage if I don't have to FL size is that I won't drag the neck over an expander plug anymore. That's where most case stretch come's from. Want to see it? Before running a case into the FL die with the expander plug , measure it. Run the case through and then measure it again, the neck will expand more than when fired

[USSR]

Bump the shoulder is a bad word. You just bump it and the case still won't load in the rifle. You have to move the shoulder, just move the shoulder enough to let the round chamber.

My goodness, I've never seen such a bunch of guys so hung up on semantics. Bump = Move! Good Grief.

Don

[RC20]

My take as well and I am a technician for crying out loud. I eat and breath miking things, control statements, engines, bearing etc. and ad nausea.

HBC had it right. Unless we are engineers designing chambers, does it matter we call a crawler tractor a Cat or a Dozer? (keep in mind when I was a kid, Cat was the ONLY crawler you saw up here! - I got a test questions right one time because I KNEW the only oil company up here in that era the picture was from was Chevron.

I put in a complaint. I was asked why I was unhappy, I got the answer right.

NO ONE ELSE CAN GET IT RIGHT BECAUSE YOU CAN'T READ THE FLIPPING LOGO ON THE TANK!

How well did MSA go over? Yea, its still and AR and it stands for Assault Rifle.

I can flip it around and say a case measure head space. It tells you if for that case there is too much or too little.

Disagree with that and I can screw the barrel out on my Savage and change it so it does work (easily, any rifle it would do so with, front sight can be an issue!)

Ergo, the head space is longer than this case (loose) or its shorter (dang bolt won't close) probably could even come up with a scale of how tight to how many thousandths.

Or to ask another way. What does it affect in any concrete way to call it head space?

A case is a pretty close mirror image to the chamber is it not? In this day and age we can measure it to tolerances far closer than in days gone by. In days gone by it would have been good.

[rox]

Originally Posted by Don Fischer

Next losen the lock ring again and turn it down about a quarter turn and re tighten the lock ring. Run the case in again and then try it in the gun. Keep doing that till the case goes in smoothly.

That is one way to kill your brass quickly! (aside from being an incredibly coarse and crude adjustment).

A quarter turn moves a die 0.018" - that's eighteen thousandths!

As it happens I've just sat down from a bit of sizing. The chamber measures 1.631"
The brass, all 1100 cases, measures between 1.6285" and 1.6295" CHSD* - in other words between 0.0015" and 0.0025" under chamber size. This requires *much* finer adjustment than quarter turns. See Unclenick's die graduation rings:

[*CHSD = Case Head to Shoulder Datum]

[RC20]

Certainly agree with that, quarter turns are far too course.

I do have Lee O locking rings and those are easy to adjust so that is how I do it. I have a 1 1/8 inch Combination wrench hanging off a nail above my head (to adjust the CHDS).

CHSD is good acronym. It can be any point (ala my custom made tool) and then moving shoulder back (which I know I am not allowed to do but I have run with scissors, spit in the wind, tried to fight city hall etc)