Case forming 7.65 Argentine from 30-06. Which die works?

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When the Lee 7.65 dies first came out people found they are too long in the body so they will not size a case that will fit a 7.65 Argentine Mauser chamber.
The following is an investigation of the dimensions of my rifle chambers, reloading dies, factory ammo, factory brass, resized cases and a few fired cases and etc.

I have 4 rifles - 3 M1891 and a 98/09 .
This is what the chambers measure using a .375 diameter gauge ring in a Hornady gauge attached to my calipers. The set up was corrected to zero with a 7X57 gauge to minimize any shoulder angle and chamfer issues found on the tool. You will see that I cross checked these number several ways to avoid any silly errors.

This is the dimension (for each of the 4 rifles) from the bolt face/case head to the gauge diameter on the shoulder of cases that barely drag when the bolt is closed.
1.822
1.821
1.820
1.820

AMMO and virgin brass
PPU ammo measures 1.819 to 1.821. It is excellent for my rifles. This ammo might NOT chamber in a CIP minimum chamber
New PPU unfired brass measures 1.818. Ditto
New Norma factory ammo measures 1.812 to 1.816 (more variable and a little shorter than the chambers) You can see below that it more nearly matches the CIP minimum drawing
New Norma unfired brass measures 1.815 ditto for the Norma ammo comments

Reloading dies
These sizes were all taken with the FL sizer or trim die down hard againt the shell holder. The same shell holder was used for all the dies. The shell holder measured exactly .125 deep.
Each case was cycled in and out of the dies 4 to 6 times without an expander until I thought the brass was not moving the shoulder back any more. At the end of each sizing stroke I let the ram dwell in the up position for 3 to 4 seconds so the brass had time to creep and take a set if it was still moving. My goal was to duplicate the inside length of the die as exactly as possible using FL sized brass.
Most of the cases formed were commercial once fired .30/06 that had been trimmed. If you cycle your brass only once during FL sizing it may be .002 longer than my results. I was using a RCBS Rockchucker press.

The Lee FL sizer measures 1.838" using the same .375 gauge diameter on a FL sized case. This is way too long - about .018 to .020 too long.

I have 2 RCBS FL sizer dies that measure 1.818 and 1.819. Just right in my opinion for my chambers.
I have another RCBS die - this one is a trim die and it measures 1.816 - Again RCBS gets it about perfect.

I have a modern Lyman FL die (less than 10 years old) an it measured 1.814 - a little bit short but....more later

I have a set of older Pacific dies and they measure 1.797 - not even in the right ball park avoid these at every opportunity. They are way the heck to short - even dangerous.
I have an old CH trim die that measure 1.781 - even worse. These cases might separate when fired. This die was not made by the current CH die company but it predecessor

Gages drawings and headspace gauges
I also have a Wilson Case 7.65 Mauser case gage that checks from the head to the shoulder. Wilson gauges are well known for exacting accuracy. My formed cases agreed with the Wilson tool and it agreed with the RCBS dies. Other Wilson gages also agreed with my Forster headspace gauges in several other calibers mentioned below.

There are no SAAMI documents for this cartridge but there are CIP drawings. The only problem is the CIP drawings are dimensioned using a different datum structure and they are not toleranced.
Therefore I took the Minimum CIP chamber drawing and used the conventions for SAAMI GO, NO GO and Field gages and applied them to the CIP minimum drawing.
To get the dimensions to the .375 gauge ring I had to create a spreadsheet that could calculate the SAAMI numbers from the CIP numbers because the geometry that locates the shoulder is defined in a different manner.
To test my spreadsheet trigonmetry I double checked some of the CIP drawings for American loaded rounds against the SAAMI drawings.
The test drawings included the 6.5X55 Mauser, 7X57 Mauser and the 8X57 Mauser. I got exactly the same numbers. I used those three because I also have a Wilson case gage for each and a set of Forster headspace gages for each. I can tell you that the Wilson Gages, the Forster go gages and my numbers agreed exactly to within .001. They are even better when comparing with a .0005 dial test indicator.

Here are the numbers for the CIP 7.65 drawings

Minimum chamber 1.816 I called this the GO gage length. This is the number calculated directly from the CIP MIMIMUM Chamber drawing. This seems to be the target for the Lyman FL die.

No go chamber 1.820 I just added .004 for the NO GO (If you add .005 the number is 1.821 for some SAAMI gauges the steps are .005 but I prefer .004) Seems to be the target for the RCBS dies.
Field chamber 1.824 I added .008 to the min chamber (If you add .010 the number is 1.826)

I have used my personal judgment in the No Go and Field dimensions. If you prefer you can use your own numbers.
My goal was to determine all I could from my dies, my ammo, my brass, my chambers and the existing standard CIP drawing.
Since I control my ammo head to shoulder dimension when I reload it I know what dimension to make it to fit my rifles.

I also know what dimensions Norma and PPU ammo and brass are produced at.
I also measured 2 of the SF 81 Argentine military cases at 1.820. Both of these cases seemed to have the wrong shoulder shape and chambered tightly in my rifles.

For my rifles I will load with the head to datum length set at 1.821. If that is too tight for the two tighter rifles then I will load them at 1.820.

Finally case length over all

CIP Min is 2.110 CIP max is 2.114

My chambers measure around 2.125 I will trim my cases when they are longer than 2.122. I get a little bit longer neck this way.
There is no danger from this. If the case if FL resized, when it is fired it will shorten .004 to .007. It will lengthen when resized. Always check your cases for over length each time they are reloaded if you decide to leave them long.

If you have one of the Lee dies that are too long you can get it cut off so it produces brass to fit your rifle.
You should have the capability to measure your chamber and your die before modification. Otherwise you are going to be doing a cut and try process that may not work so well if you are not careful.

You can also complain to Lee and see what they say.

From my measuring and checking RCBS dies are the way to go.