Headspace AGAIN has me puzzled

[midnightreloader]

So I normally neck size my 30-06 brass. I recently read an article by German Salazar on the benefits of full length sizing. Here's the link if you are interested http://riflemansjournal.blogspot.com...n-changes.html I decided to give full length sizing a try. So I put some new never fired Lapua brass in the RCBS headspace mic and it read 0. What has me totally lost is when I put my fired brass in the gauge it still reads 0. Does anybody know what's going on or how I should go about sizing these?

If this helps the load is 52.3 grains of IMR 4350 with a 185 grain Berger VLD hunting bullet in Lapua brass. Rifle is a newer Model 70.

Thank you,

-Adam

[bubbala]

not familiar with the rcbs gauge. but one firing may not be enough to move the shoulder enough to need bumping.

[OpenSightsOnly]

So I normally neck size my 30-06 brass. I recently read an article by German Salazar on the benefits of full length sizing. Here's the link if you are interested http://riflemansjournal.blogspot.com...n-changes.html I decided to give full length sizing a try. So I put some new never fired Lapua brass in the RCBS headspace mic and it read 0. What has me totally lost is when I put my fired brass in the gauge it still reads 0. Does anybody know what's going on or how I should go about sizing these?

If this helps the load is 52.3 grains of IMR 4350 with a 185 grain Berger VLD hunting bullet in Lapua brass. Rifle is a newer Model 70.

Thank you,

-Adam

If you have a 9mm case, you can use that to measure, comparatively, the datum line of your 30-06 brass, fired case vs. sized case.

It's cheaper and it works.

Then again I ended up with a set of cartridge headspace gauges

[ar15barrels]

So I put some new never fired Lapua brass in the RCBS headspace mic and it read 0.
What has me totally lost is when I put my fired brass in the gauge it still reads 0.
Does anybody know what's going on or how I should go about sizing these?

If your fired cases are measuring "0", adjust your dies so that they are -0.001" after sizing.

[JMP]

Never fired brass to fired brass is not a good comparison. When you fire the brass, the shoulder will pop out more and the shape will be more crisp. This can result in differences. It's better to use your fired brass, then take of 0.001" as ar15barrels indicated.

[midnightreloader]

Ok thanks guys. I really appreciate it.

-Adam

[fguffey]

So I normally neck size my 30-06 brass. I recently read an article by German Salazar on the benefits of full length sizing. Here's the link if you are interested http://riflemansjournal.blogspot.com...n-changes.html I decided to give full length sizing a try. So I put some new never fired Lapua brass in the RCBS headspace mic and it read 0. What has me totally lost is when I put my fired brass in the gauge it still reads 0. Does anybody know what's going on or how I should go about sizing these?

I do not have these problems, I am sure Mr. Salazar can measure the length of a chamber from the shoulder to the bolt face. I honestly believe a reloader can do the same.

I know before I chamber a round if the bolt will close.

Never fired brass to fired brass is not a good comparison.

I disagree, if a new/never fired case will allow the bolt to close the case is shorter from the shoulder to the case head than the chamber from the shoulder to the bolt face. For reloaders that can keep up with measurements they should be able to determine the effect the chamber had on the case when fired.

That brings up back to the OP's question about full length sizing to minimum length or neck sizing. What is the difference? It seems to me there should be members that can come up with a few factors that effect differences.

I have chamber gages, I have barrels, I cut off barrels and use them for chamber gages.

Then there methods and techniques for die adjustment, when sizing a case a reloader can determine if the case got sized, meaning? Did the press win or did the case win. I can determine the winner before lowering the ram, or I can remove the die from the press before lowering the ram. My shell holders have a deck height of .125", in the perfect world I should have .125" case head protrusion from the die if the case is full length sized/restored to minimum length.

F. Guffey

[fguffey]

Headspace has me puzzled

I have no infatuation with head space. To most everything has head space and every gage is a head space gage.

F. Guffey

[midnightreloader]

If your fired cases are measuring "0", adjust your dies so that they are -0.001" after sizing.

I tried doing this and I cannot get a -.001 measurement. I moved the die every which way and after an hour gave up. Does anyone know why I cannot get the die to go below 0? The only reason I could think of was that since 0 on the mic is SAAMI min spec that the lee die cannot adjust past this?

Thanks again,

Adam

[midnightreloader]

Just went and tried again. This time when I screwed the die down further the headspace went from 0 to 1 on the mic. I am I missing something obvious here because this isn't a complicated concept, yet it has me about throw my press out the window.

Thanks for any help,

Adam

[eric n]

The only thing that will grow if you screw it down farther is case length

Make a dummy round with your necksizer and if it chambers easily then load a batch, shoot, then re measure. It takes a few firings to form to your chamber sometimes.

[ar15barrels]

Just went and tried again. This time when I screwed the die down further the headspace went from 0 to 1 on the mic. I am I missing something obvious here because this isn't a complicated concept, yet it has me about throw my press out the window.

Excellent.
What happens while sizing is that you SIDES of the case are getting pushed in BEFORE the shoulder of the case reaches the shoulder in the die.
The fact that turning your die DOWN caused the shoulder to move UP is a good sign.
That means that the die is responding to adjustment.
Keep adjusting the die DOWN in the press in very small increments and keep measuring sized cases.
Eventually, the will reach the point where the case shoulder meets the die shoulder and then further adjustment will cause the case shoulder to get shorter instead of longer.

Here is a little tip:
Take a piece of masking tape about 2" long and make a series of marks on it 1mm apart. so it's like a tape measure.
Now, wrap the tape around the part of your die which is 7/8" diameter.
Imagine there is a marker on your press, or even make a pencil mark on the press.
As you are turning the die in the press, those marks on the die should pass that mark on the press.
Each mark that passes is a 0.001" adjustment.

[ar15barrels]

The only thing that will grow if you screw it down farther is case length(neck).

False.
The SHOULDER on the case grows UNTIL it reaches the shoulder in the die.
The same taper that makes the case OAL grow is effecting the WHOLE CASE, not just the neck.
Last I checked, the shoulder on the case was in between the neck and the body and the whole body is getting squeezed down during sizing.
The angle of the die makes the brass extrude upwards into the die during sizing.

[eric n]

False.
The SHOULDER on the case grows UNTIL it reaches the shoulder in the die.
The same taper that makes the case OAL grow is effecting the WHOLE CASE, not just the neck.
Last I checked, the shoulder on the case was in between the neck and the body and the whole body is getting squeezed down during sizing.
The angle of the die makes the brass extrude upwards into the die during sizing.

You are right Randall,I shouldn't have added neck and left it at case length.

[midnightreloader]

Excellent.
What happens while sizing is that you SIDES of the case are getting pushed in BEFORE the shoulder of the case reaches the shoulder in the die.
The fact that turning your die DOWN caused the shoulder to move UP is a good sign.
That means that the die is responding to adjustment.
Keep adjusting the die DOWN in the press in very small increments and keep measuring sized cases.
Eventually, the will reach the point where the case shoulder meets the die shoulder and then further adjustment will cause the case shoulder to get shorter instead of longer.

Here is a little tip:
Take a piece of masking tape about 2" long and make a series of marks on it 1mm apart. so it's like a tape measure.
Now, wrap the tape around the part of your die which is 7/8" diameter.
Imagine there is a marker on your press, or even make a pencil mark on the press.
As you are turning the die in the press, those marks on the die should pass that mark on the press.
Each mark that passes is a 0.001" adjustment.

Thanks again Randall. Worked like a charm. You're a life saver.

-Adam