Fired brass headspace grows after FL resizing

[longrangeprecisionshooter]

I was re-sizing some 4-5times fired 6 Dasher Alpha OCD brasses using a newly received FL sizing die, found the headspace grows about 0.0015-0.0020" after resize.
Fired brass headspace: 1.1935-1.1940"
After resizing headspace: 1.1950-1.1955"

1.My initial setup was, push the press handle all the way down(rise the ram all the way up) and screw the FL sizing die all the way down to touch the shell holder firmly. The decapping pin, expander and rod assembly is uninstalled.

2.Then I made some changes based on my initial setup, after lower the press ram down, I give the FL sizing die additional 1/4 turn towards the shell holder, in case there were some gap, now the shell holder and the bottom of the die are contacting tightly.
But, same result.

I repeated the above 2 methods using Redding competition shell holders, tried 0.002, 0.004 and 0.010 ones, all give the same result.

3. Based on my initial setup, I give the FL sizing die more adjustment going down, add from 1 full turn to 3 full turn step by step. At some point I wasn't sure exactly how much adjustment I made, probably around 2 full turns, it actually resized the brass with increased headspace from 1.1955" down to 1.1910". Unfortunately, I lost that point when I tried to back the FL sizing die up a little bit so it will size the brass to 1.192" and I can't find where that point is after.

Here is a photo of the brass after resized with black marker covers from neck/shoulder joint to the top of the body.
It seems there are contact/force applied on the body and the joint between body and shoulder, but no contact or only a minor scratch on the shoulder.



4. Tried with a Redding Type S FL sizing die using my initial setup, it works as expected, sized brass to 1.192+/-0.0005" including those brasses I tried above with increased headspace.

As I suspect the new sizing die might have a longer body, I used depth rod on my caliper measured the depth from the bottom of the die to the brass body and shoulder joint point inside the sizing die, I got approximately:
1.100+/-0.005" for the new FL sizing die
1.070+/-0.002" for the Redding Type S FL sizing die
Seems there is 0.025-0.030" difference.

Does this sounds like a manufacturing issue with the sizing die? or something I did wrong. Thank you.

 

[Fast14riot]

TL/DR

If base to shoulder is growing during sizing, the die isn't touching the shoulder. Its squeezing the brass and pushing it up.

 

[JSH]

I have a couple of rifles that are minimum headspace. I had to “fix” a shell holder to get any shoulder bump.

 

[Texas Solo]

Try using a shorter shell holder.

 

[JFrank]

Well said by others above, no need to double post.

Jim

 

[BoydAllen]

Your whole going more than a fraction of a turn beyond where the die touches a standard shell holder is totally wrong....totally. Like someone else posted, you probably need to try a shorter than normal shell holder. You can make one with a sheet of wet and dry on a flat surface, checking the thickness for evenness as you go, and making corrections by changing technique. As has been said, when a case does not reach the shoulder in the die, the constriction in the body diameter will force the shoulder forward. Ordinarily, there will be enough room for normal adjustment so that you can lower the die so that its shoulder can push the case shoulder back. All that you are doing with your extremes is stretching the press.

 

[SKWERLZ]

TL/DR

If base to shoulder is growing during sizing, the die isn't touching the shoulder. Its squeezing the brass and pushing it up.

^^^^^

 

[6BRA]

Isn't Alpha brass made for Alpha reamers?

 

[longrangeprecisionshooter]

Try using a shorter shell holder.

Thank you.

Correct me if I got it wrong, using some sort of sand paper to reduce the depth between the top of the shell holder to the case head, just like how Redding competition shell holder works right?

 

[longrangeprecisionshooter]

Your whole going more than a fraction of a turn beyond where the die touches a standard shell holder is totally wrong....totally. Like someone else posted, you probably need to try a shorter than normal shell holder. You can make one with a sheet of wet and dry on a flat surface, checking the thickness for evenness as you go, and making corrections by changing technique. As has been said, when a case does not reach the shoulder in the die, the constriction in the body diameter will force the shoulder forward. Ordinarily, there will be enough room for normal adjustment so that you can lower the die so that its shoulder can push the case shoulder back. All that you are doing with your extremes is stretching the press.

Thanks, I doubt that too when someone suggested giving a try.

So I guess, either cut the bottom of the sizing die by some professionals with a lathe or shorten a standard shell holder(pushing the brass up) would be my options right?

 

[Bill Norris]

Thank you.

Correct me if I got it wrong, using some sort of sand paper to reduce the depth between the top of the shell holder to the case head, just like how Redding competition shell holder works right?

Exactly.

 

[marine52]

Thank you.

Correct me if I got it wrong, using some sort of sand paper to reduce the depth between the top of the shell holder to the case head, just like how Redding competition shell holder works right?

Same principle but different direction. The Comp Shellholders sold by Redding and the modular Shellholders sold by Area 419 reduce the shoulder bump relative to a standard shellholder. The standard shellholder has a .125” distance between the surface that the case base sits on and the top of the shellholder ledge. Comp shellholders allow this distance to vary in order to maintain a solid die-to-shellholder contact. For example, the +10 shellholder has this distance at .135” , allowing a solid die-to-shellholder contact but providing 0.010” less bump.

 

[JSH]

I know those who have shortened dies. You better be able to measure tapers and angles on a die and your brass, or you could well make another problem when you “fix” one.

To add to what Boyd said. If you have the Redding shell holders and their “short” one is still not enough, measure it and check against your sacrificial shell holder so you have an idea of how much material you need to remove. All shell holders are not created equal, don’t ask how I know.

 

[Turpentine]

This may be an absolutely stupid comment but I figure I'll make it anyway. I have had the headspace actually increase, particularly using tough military brass, due to not sufficiently lubricating the inside of the necks. When the expander ball pulls back through the neck the lack of lube would cause it to pull and lengthen the case and give inconsistent results. Enough of this pulling, stretching will actually weaken the case walls. Like I said I may be totally off base but figured I would throw it out there. It definitely wouldn't be the first time Ive been wrong.

 

[TIMO]

This may be an absolutely stupid comment but I figure I'll make it anyway. I have had the headspace actually increase, particularly using tough military brass, due to not sufficiently lubricating the inside of the necks. When the expander ball pulls back through the neck the lack of lube would cause it to pull and lengthen the case and give inconsistent results. Enough of this pulling, stretching will actually weaken the case walls. Like I said I may be totally off base but figured I would throw it out there. It definitely wouldn't be the first time Ive been wrong.

Not wrong or stupid. I think most here do not use the expander ball when sizing.
Tim

 

[BoydAllen]

Exactly.

Wrong. The the Redding shell holder set starts with a standard shell holder and the others are taller, in .002 increments. To get a shorter shell holder you will have to make it, but shell holders are inexpensive and the process is not difficult.

 

[Bill Norris]

Wrong. The the Redding shell holder set starts with a standard shell holder and the others are taller, in .002 increments. To get a shorter shell holder you will have to make it, but shell holders are inexpensive and the process is not difficult.

Same principle just reversed.

 

[LVLAaron]

Isn't Alpha brass made for Alpha reamers?

Not really. Alpha brass was available a long time before they had reamers. The marketing says they're made for each other... in other words... they're made for saami specs

 

[JSH]

This may be an absolutely stupid comment but I figure I'll make it anyway. I have had the headspace actually increase, particularly using tough military brass, due to not sufficiently lubricating the inside of the necks. When the expander ball pulls back through the neck the lack of lube would cause it to pull and lengthen the case and give inconsistent results. Enough of this pulling, stretching will actually weaken the case walls. Like I said I may be totally off base but figured I would throw it out there. It definitely wouldn't be the first time Ive been wrong.

I saw this a lot years ago. Today things are some what better.
I refuse to put a dirty case in any of my dies, so they get cleaned before I size. I the rattle the cases around in a box until majority is mouth up, then apply my spray lube. Then I let them set till the alcohol has flashed off. I then clean them again. The lube in the case and on the mouth cause powder to stick and I get wonky results with lube residue in the mouth. This is with an expander ball on some ammo I load. Works for me.
Bushing dies are whole different thing in my shop.

 

[Tommie]

Not really. Alpha brass was available a long time before they had reamers. The marketing says they're made for each other... in other words... they're made for saami specs

The Dasher is a SAAMI cartridge?