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Full Length Resizing Die

How-To
Adjust Full Length Resizing Die

For Full Length or Neck sizing only. 



 

The first thing you need to understand is "Cam over". To see this in action, mount your shell holder in the ram of your press with no die in place. Get close and watch closely. Raise the ram of the press to its highest point of travel. Move it very slowly at the top of the stroke and watch it very closely. You will notice that the ram reaches the top of its travel slightly before the handle reaches the end of its travel. This is visible in the action of the ram. It will move up to its maximum point then retreat very slightly. Very slightly really means VERY slightly. Usually only .003 to .010.

This is easier to see if you screw in the resizing die until it lightly touches the top of the shell holder with the ram all the way down as far as it will go and at rest. Now move the ram up and down. Before the ram reaches its maximum - up - travel, the shell holder will touch the bottom of the sizing die. The press and or the linkage will spring a little and then the ram will retreat a little and your shell holder will be back into easy contact with the bottom of the die. Next screw the die out about one eighth turn ( approximately 0.009") Now move the ram up and down there will be a very small gap when the ram is at the top of its stroke and the gap will widen a little as the handle continues to its maximum travel.

Most instructions state that you should adjust the die to touch the shell holder with the press handle at its maximum travel. This will mean that it will be a few thousandths below the top of the ram travel and the ram will cam over when it hits the bottom of the die. This will insure that the cartridge is pressed into the die to its maximum depth, thus full length sizing it ( At least to the maximum amount possible with this die. )

But, what if the die interior is shorter than your rifle's chamber in the length from the head of the case to the shoulder of the case. It will set the shoulder back just a bit. When you fire that case next time, it will push the shoulder forward. When you reload it next, it will push that shoulder back. Do you see where this is going?

The photos with this article were created for multiple lessons:

1) How to set your full length resizing die to resize cases to "exactly" fit your rifle chamber ( as exactly as possible.)

2) How to set your full length resizing die to neck size only.

3) How to set your full length resizing die to correct cases that have been fired in a rifle with a longer headspace measurement than yours and which will not allow your bolt to close.

 

A few ideas about adjusting loading dies, sizing or other types.

 

Reloading dies are normally 7/8" n diameter and threaded 14 threads per inch. This knowledge makes accurate adjustments fairly easy.

Since one full turn of the die body turns advances the die into ( or our of ) the press by 1/14" we can calculate that that turn moves the die body 1.00/14"  = .0714"

Other amounts can be estimated as follows:

One full turn = .0714"
One fourth turn = 0.0179"
One sixth turn = 0.0119"
One eighth turn = 0.0089"
One twelfth turn = 0.0059"
Turn the width of set screw = .0027"

Sixth and Eighth turns are easy to estimate if your die body has a hexagonal locking ring, one sixth turn moves one point to the location of the next point. If your die has octagonal locking rings you can get one eight turn in the same manner.

Photo instructions:  Expand images with the control key plus the mouse wheel or maximize them by clicking on them.

The Control Key Plus the Mouse wheel will zoom the entire page.  Control + Wheel Forward zooms in. Control + Wheel back zooms out.

Clicking on the image will open it in a new window at the image's maximum resolution.

A word about step numbers. These steps are the steps I took in this die setting exercising. Your exercise may have more or less steps depending on the condition of your case and on how good you are at guessing how far to thru the die between steps.

This case will be the subject of this discussion. This is a range pickup. It was selected because it has a high pressure ring around the head of the case and because it has been reloaded before with only neck sizing.

The combination of excess pressure and only partial sizing suggested that it will quite likely not fit the chamber of my Remington 700 .223 rifle.

Expand the photo and notice the following:

1:  Vertical striations from the resizing die.

2:  Circular ring around the neck of the case marking the extent of the neck sizing.

3:  High pressure ring. This ring is actually much brighter "in real life". The lights make the rest of the case look brighter and this ring does not shine as much in the photo as it does when viewed first hand.

When I got it to the shop, a quick test verified that it would not even nearly fit the chamber of my Remington 700. 

Fired Rifle Casing

Step one:

The first step in this process is to blacken the case.

I normally do this with a black marker but the marking fluid was so reflective I couldn't get good photos because of the reflected glare.

In this case, I used mold release. Anything that will make a very thin coating will do. It doesn't have to be black but it should be a dark color that will contrast well with the color of the underlying brass cartridge case. We will be looking for the color of the brass shining through the black coating in the following process.
 

Step 2:

A quick measurement of the length of the case neck tells me it is a little less than 1/4" in length. To be precise, I can check the loading manual and determines that it is actually 0.203" in length.

Now run the ram to the top of its stroke and insert the die until it is touching the shell holder.

Calculate how far to back out the die so it just barely touches the mouth of the case. The Die backs out of the press by 71/1000ths of an inch for each full turn of the die body. If we back the die out two full turns it will be about .143 higher than before. It should resize only the first 60 thousandths of the neck.

By calculating the length of the neck in terms of turns of the die, we get 0.203" / 0.0714 = 2.84 turns of the die will approximately equal the length of the neck

Now carefully raise the ram to its top position and resize only the top part of the neck.

Remove the case and inspect your blackening. It should be mostly removed from the mouth of the case down to the extent to which the die resized the neck.
 

Resizing pass 1 



Step 3:

A quick visual inspection tells you you have sized less than half the length of the neck so you can easily go another full turn.

Screw the die into the press one full turn and resize again.

This time you have resized more of the neck of the case and notice that bright ring around the shoulder of the case. This time you reduced the shoulder and wiped part of the black off the body of the case just below the shoulder. In this case we are still quite away from touching the shoulder but from our above calculation that the entire length of the neck is 2.84 turns of the die, we know we cannot turn it a full turn this time without impacting the shoulder. At this time we are not ready to touch the shoulder.


Resizing pass two 

Step 4:

Turn it another half turn and resize again. This time note that you are resizing almost the entire neck of the case. and you have wiped quite a bit of the blackening off the body of the case just below the shoulder.

We are resizing the body of the case here because this case was deliberately chosen because it was over stretched.  Your cases may not be sizing the body of the case at this point.

Resizing pass three 

Step 5:

Continue the above steps turning the die in very slightly, multiple times. Turn it just far enough that the set screw in the locking rings moves by an amount equal to its own width. This will move the die by about 0.002 to 0.003.

You will reach a point where the blacking is wiped off the shoulder and the brass is shining through.

In this case, it appears that the neck has not quite been fully resized but the shoulder has been touched. ( The shoulder may not have actually been touched but the shoulder of the die was within the thickness of the blackening from touching the shoulder.

Resizing pass four 

Step 6:

Clean the case thoroughly. Try it in your rifle. If the bolt closes easily, you have a perfectly NECK SIZED cartridge case. If your intention is to neck size only, you can stop here.

At this point, this case has been sized the minimum amount to correctly size the neck and to apply minimum sizing to the back and not set the shoulder back.


 

 

Step 7:

In this case, not surprisingly,  the case would still not chamber in my rifle.

Now I clean the blackening out of the resizing die with a spray degreaser/cleaner like Birchwood Casey Gun Scrubber or Berryman's B-12.

Since I have degreased the inside of the die body, I need to apply a little sizing lube to the cartridge case. ( very little )

Now I turn the die into the press by one half the width of the set screw in the lock ring. This means the locking ring is screwed up until the set screw moves approximately one half its diameter. Then the die is turned back in until the locking ring is snug. This will move the die by less than 0.002".

(You can also do the same thing by turning the locking ring up a couple of turns and locking it in place. Then the die is free to turn in or out until you are satisfied and then you can screw the locking ring down and lock it place with the set screw.)

Yes! This is nit picking but I want the adjustment to be as precise and exact as I can possibly make it.

Resize the case with the new die setting and try it in the rifle again. Continue this until the bolt closes with no effort. It should feel just like closing the bolt on an empty chamber.  If it is a little snug, you have one more adjustment to go. You have now set the shoulder back to the exact maximum length that will easily fit your chamber.


 

Step 8:

With  most dies, you will notice that the die body is very close to contacting the top of the shell holder. That is because most dies are made to very accurate and precise tolerances.

If it is not touching the top of the shell holder, you might be tempted to go ahead and turn it in until it does touch the shell holder. This will result in a more "full length" resizing of the cartridge and will probably size it closer to factory tolerances than the method we have described here. If you are reloading for multiple rifles or multiple people, this is probably a good thing.

If you are reloading only for your pet target or hunting rifle and want to achieve maximum case life and maximum accuracy, don't do it.


 

 

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