Head Spacing, FL Sizing Die, Shoulder Bump

[16tpi]

It's unclear to me also. He seems to want to share a press in the field that guarantees precise shoulder set-back from one die to another? I don't believe he grasps the fact that not every piece of brass workhardens at the same rate- no matter if from the same lot, fired and sized the same # of times with the same loads. ....or that variations in shoulder set-back affects accuracy adversely.

Yes I understand completely about how the brass property changes by the number of firings and different lot #s.

I shoot 6mm Dasher the dies are available, but the brass has to be made by fire forming. So there is not brass to set head space from. A new brass is not a head space gauge by no means. It may give you a rough estimate guess about where you are setting the head space.

If you are setting the head space you set it up just like you do when setting a die up to bump the shoulder to get the perfect feel of bolt closure.

I been reloading for years as well. Lyman is the first set of dies I had. I have talked to Redding about this as well. They set there dies with a .008 bump at the factory and .005 on 40 degree shoulders. This in itself tells me that it tells me that it may be my die tho I would still have to bump the shoulder even if I shaved .003 off the bottom of it. Because it takes .0105 to achieve the .0015 bump that I'm looking for, for the feel of a good bolt closure.

The shell holders are a standard .125 I don't care who makes it. The dies on the other hand are not , they do set it up from the datum line which is mid shoulder to the base of the case.

The question was to make it where I can set my die up and form my brass with any press to fit my rifle and do away with bumping the shoulder? And setup the die normally with a standard shell holder.

And where would you correct the problem of having to bump the shoulder, would you lengthen the chamber by add to the base of the head space gauge, or off the bottom of the die?

After going back and reading my question of the first post. It was suppose to be add to the head space gauge.. Sorry! After all the info that has been shared it has been very helpful.

 

[16tpi]

It is corrected sorry for the mistake.

 

[dkhunt14]

The shell holders are a standard .125 I don't care who makes it. The dies on the other hand are not , they do set it up from the datum line which is mid shoulder to the base of the case.

All shell holders are not .125. They vary from one to one and maker to maker.

The question was to make it where I can set my die up and form my brass with any press to fit my rifle and do away with bumping the shoulder? And setup the die normally with a standard shell holder.

All presses vary from brand to brand and model to model. You can't set up a die for one press and expect same results in another.

And where would you correct the problem of having to bump the shoulder, would you shorten the chamber by add to the base of the head space gauge, or off the bottom of the die?

You change your die height after measuring the fired case. In most cases you need to alter die or shellholder.

After going back and reading my question of the first post. It was suppose to be add to the head space gauge.. Sorry! After all the info that has been shared it has been very helpful.

You need to find somebody to show you how to measure cases and set up your dies. Matt
You need to click on expand at bottom of your post above to see my answers to your questions.

 

[DanSavage]

I would think to be able to use any press with a standard shell holder the easiest solution is to have your die ground down on the bottom so that it would be capable of bumping "your" fire formed brass .008"-.010", to have an extra safety margin. Though you don't want to bump more than .002-.003"

I do realize that head spacing off of new Lapua brass is not a means of "book tolerance threshold" but it is a way off assuring me that the brass will see very minimal stretching from the original state in which it was created.

 

[dkhunt14]

Yes I understand completely about how the brass property changes by the number of firings and different lot #s.

I shoot 6mm Dasher the dies are available, but the brass has to be made by fire forming. So there is not brass to set head space from. A new brass is not a head space gauge by no means. It may give you a rough estimate guess about where you are setting the head space.

If you are setting the head space you set it up just like you do when setting a die up to bump the shoulder to get the perfect feel of bolt closure.

I been reloading for years as well. Lyman is the first set of dies I had. I have talked to Redding about this as well. They set there dies with a .008 bump at the factory and .005 on 40 degree shoulders. This in itself tells me that it tells me that it may be my die tho I would still have to bump the shoulder even if I shaved .003 off the bottom of it. Because it takes .0105 to achieve the .0015 bump that I'm looking for, for the feel of a good bolt closure.

The shell holders are a standard .125 I don't care who makes it. The dies on the other hand are not , they do set it up from the datum line which is mid shoulder to the base of the case.

The question was to make it where I can set my die up and form my brass with any press to fit my rifle and do away with bumping the shoulder? And setup the die normally with a standard shell holder.

And where would you correct the problem of having to bump the shoulder, would you lengthen the chamber by add to the base of the head space gauge, or off the bottom of the die?

After going back and reading my question of the first post. It was suppose to be add to the head space gauge.. Sorry! After all the info that has been shared it has been very helpful.

All shell holders are not .125. They can vary from one another and from company to company.

You can set up your die to bump the shoulder. You really should bump the shoulder every time you size. You can not take your setup die from one press to another and expect it to bump the same.

In most cases You should be able to set up the die to bump the shoulder without removing anything from the die.

I think you should find a mentor that can show you how to set up a Die and measure headspace on a fired Case. Matt

 

[16tpi]

You need to find somebody to show you how to measure cases and set up your dies. Matt
You need to click on expand at bottom of your post above to see my answers to your questions.


[/QUOTE

No I am well aware how to set my dies up. And if the shell holder vary it is plus or minus .001. .125 is a nominal for the shell holders. Presses are just as you described, each of its own, they do the same purpose in relation to reloading.

So I know your answer would be to take it off the bottom of the die, because of to not use a bump shell holder. Thank you dkhunt14.

This question is not to be mad a pissing contest if you don't want to help answer an honest question please don't reply.

The setup is not the problem..

 

[16tpi]

I would think to be able to use any press with a standard shell holder the easiest solution is to have your die ground down on the bottom so that it would be capable of bumping "your" fire formed brass .008"-.010", to have an extra safety margin. Though you don't want to bump more than .002-.003"

I do realize that head spacing off of new Lapua brass is not a means of "book tolerance threshold" but it is a way off assuring me that the brass will see very minimal stretching from the original state in which it was created.

I would think to be able to use any press with a standard shell holder the easiest solution is to have your die ground down on the bottom so that it would be capable of bumping "your" fire formed brass .008"-.010", to have an extra safety margin. Though you don't want to bump more than .002-.003"

I do realize that head spacing off of new Lapua brass is not a means of "book tolerance threshold" but it is a way off assuring me that the brass will see very minimal stretching from the original state in which it was created.

Thank you for your thoughts.

 

[dkhunt14]

A bump shell holder bumps more. It is one you make less then .125. In most cases you can set a die up to bump without taking off the die. I am not tuning it into a pissing contest. You just are not understanding everybody. That's why I suggested somebody to show you. Matt

 

[DanSavage]

You probably know this 16tpi but sometime's when your sizing a piece of fire formed brass, the head spacing of that brass will actually increase to a degree until the case can get in far enough for the die to push the shoulder back.

 

[BoydAllen]

Dan,
It is not the oversized chamber that requires a small base die, but rather one that is on the tight side. Think about it for a minute. The die needs to be smaller than the fired brass, and the larger the chamber, the more that a given FL or body die with size the fired brass.
Boyd

 

[Patch700]

This all leads to having a closely matched die to chamber... It'd be slightly simpler if we were dealing with cases that for example were .4700" at the base and .4680" at the neck shoulder junction..

But when you're dealing with cases that have tapers more along the lines of .4700" base and .4550" at the neck shoulder junction things change in lots of places before you actually get from point A to point B and it gets compounded by having mismatched die to chamber specs.

Even in a perfect world there is still going to be variance... Show me a guy who says he can control bump to .001" repeatedly on ALL his cases by merely using a certain shell holder (without adjusting the die) and I'll show you a guy who should play the lottery on a regular basis.

 

[DanSavage]

Dan,
It is not the oversized chamber that requires a small base die, but rather one that is on the tight side. Think about it for a minute. The die needs to be smaller than the fired brass, and the larger the chamber, the more that a given FL or body die with size the fired brass.
Boyd

I stand corrected Boyd,, I should have said sometimes a standard sizing die can't size down the case enough and a small base die is needed.

 

[16tpi]

Thanks guys I really appreciate your thoughts and answers. In my opinion I think all had good answers.

P.s. I have seen were threads turn in to that kind of thing, just didn't want it to be a battle when not on the field learning searching for answers. Thank you again.

 

[fguffey]

A bump shell holder bumps more. It is one you make less then .125. In most cases you can set a die up to bump without taking off the die. I am not tuning it into a pissing contest. You just are not understanding everybody. That's why I suggested somebody to show you. Matt

I do not have fewer than 200 shell holders; and now? I have to start over because ‘the bump’ has moved from the cam over press, to the die and now the shell holder. I have shell holders that do not have a deck height of .125”. My shell holders that do not have a deck height of .125” got that way by a misinformed reloaders that lowered the deck height by grinding the top of the shell holders. I also have dies have been modified. A reloader with a few shop skills can determine the ability of a die and shell holder to return a case to minimum length ore as they say ‘full length size’.


I have never found it necessary to grind the top of the shell holder or the bottom of the die. I do have one set of Redding Competition shell holders; of the 5 in the set 3 are off by .001” each, not a problem. I paid $5.00 for the set.


At one time the length of the chamber for the 30/06 was measured from the case body/shoulder juncture to the bolt face. And the datum is not located half way between the shoulder/neck juncture and the shoulder/case body juncture. The 25/06. 270 and the 30/06 have the same datum of .375”.


F. Guffey

 

[BoydAllen]

F Guffey,
I find your characterization of those that have taken material off of the top of their shell holders as being misinformed is inaccurate and misleading. There are times where this is the smart thing to do. If a die is cut a little too deep for a particular chamber, that was cut to absolute minimum, and the brass being used is particularly hard, this may be the easiest and least expensive way to solve the problem. In the world of short range benchrest, this sort of thing is common, and they shoot the most accurate rifles and ammunition that are available. I will say that it is also probably common for fellows to make the mistake of not measuring shoulder bump, and setting dies by feel alone, and that they may bump in reference to a fired case that has not expanded to the chambers full dimension from shoulder to bolt face.
Boyd Allen

 

[fourpower]

Okay I have been reloading for years, maybe someone has noticed this before or maybe not. If you are bumping your shoulder on your brass, the question is WHY? I have been looking to find the answer. In my line of work as an A Tool & Die Maker you have to give dies clearance to form the material the dies are forming. If it doesn't have the correct clearance the die will rip the material or leave it looking like a pie pan wrinkled up.

Now I have taken the time to setup my press to find out the why. I'm guilty of bumping the shoulder on my brass. I have a shell holder that will let me bump the shoulder back.

TEST

I set my die up using a standard shell holder, 0.125 of an inch from where the brass sits on the holder to where the holder bumps the die. Setup an indicator on top of the die and Zero it, to see what i am reading when i bump my brass with the bump that is required to get a smooth bolt closure. I put my bump shell holder in, and set the die to where i size the brass normally, -0.0105 of and inch is the reading i get when I size a brass. Now with that being said I use my GO GAUGE to see how far the die is set from there, the reading i get is -0.009 of an inch on the GO GAUGE.
Now the math says I am bumping my brass a total of -0.0015 of an inch.

So if the head spacing is where the cause of need to bump the shoulder is, why not add .0015 to the back of the head space gauge?

If it is the die, why not take it off the bottom of the die?





Your thoughts???

I used to have same problems and worrys but not now. I got a larry willis head space tool and a benchsource annealing machine. I can set all my brass up for zero headspace or not more than -.001. this really works great on belted cases as you now headspace on shoulder not on the belt!! all my magnum cases now go at least 10 reloads and these are on the hot side. my 7mm mag has how on the 12th reload and still going strong. I use rcbs fl dies and with larrys tool can set them all at zero headspace. this tool makes life easy!

 

[BoydAllen]

There are a number of tools with which this can be accurately done.

 

[fguffey]

I find your characterization of those that have taken material off of the top of their shell holders as being misinformed is inaccurate and misleading.

Methods and techniques, I am the fan of both. I could be the only reloader that has a grinder that is perfect for reducing the deck height of a shell holder. If a reloader is going to grind the top of the shell holder or bottom of the die I suggest they determine how much metal is to be removed first. How do they do that when they have shell holders that have a deck height that is all over the place and no one can determine the die's ability to return a case to minimum length/full length sized.


My dies size a case to a length that is shorter than a go-gage length chamber. A reloader should be able to put the die and shell holder to gather with a gage when determining if the combo has the ability to size a case.

F. Guffey

I know and understand there are many reloaders that have ground the top of their shell holders and bottom of their dies. When friends tell me what they did I always ask "WHY?".

 

[ireload2]

>>>you have to give dies clearance to form the material the dies are forming<<<
This statement is not true with the brass used in cartridge cases. You are talking about forming a metal with both a punch and die.
In hand loading we do not have a punch on the interior of a case that is being formed unless it is being expanded at the neck or case mouth.

 

[ireload2]

What makes you think people do not know the dimensions of the dies and the shell holders? Both are very simple to check.
But you can measure the cases produced by a shell holder and die combo and know what they produce without measuring anything but the case.
I agree with Boyd Allen in regard to your previous post.

Methods and techniques, I am the fan of both. I could be the only reloader that has a grinder that is perfect for reducing the deck height of a shell holder. If a reloader is going to grind the top of the shell holder or bottom of the die I suggest they determine how much metal is to be removed first. How do they do that when they have shell holders that have a deck height that is all over the place and no one can determine the die's ability to return a case to minimum length/full length sized.


My dies size a case to a length that is shorter than a go-gage length chamber. A reloader should be able to put the die and shell holder to gather with a gage when determining if the combo has the ability to size a case.

F. Guffey

I know and understand there are many reloaders that have ground the top of their shell holders and bottom of their dies. When friends tell me what they did I always ask "WHY?".