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

[Parashooter]

7x57 is a tad shorter-bodied than 7.65. May present minor headspace issues that can be addressed by several standard techniques, all more or less time-consuming.



.30/06 is easy - and readily-available, free or cheap. Never tried 8x57 - not much free boxer brass around here.

[vintage hunter]

7x57 could be used in a pinch I reckon but it would require the extra step of fire forming or else you'd likely end up with excessive headspace and it's related problems.
I've used 8x57 brass to form 7.65, the forming part works out fine but of the 20 pieces I used 7 or 8 lacked enough neck tension to hold the bullet in place during recoil. A few were so loose I could seat the bullet with finger pressure only.
30-06 or 270 works best and requires the least amount of effort.
Even though new factory brass is available from PRVI now I don't like to discard brass unless I absolutely have to so it's a good way to get a few extra miles from suitable cases that would otherwise be destined for the scrap bin due to split necks. That's the biggest reason why I incorporate the annealing step in the conversion process.

[mrappe]

I tried taking out the expander-decapper from the die and then put a 0.014" feeler gauge into the bottom of the shell holder and ran the case up again in the die after annealing it and the empty case then chambered easily into the rifle. I tried loading a bullet (Moyer's cast lead gas check 303 Brit 313 dia. 180 GR FP) into the case without primer/powder and the neck bulged on on side and was too tight. I then re-sized a case with the feeler guage with a whole in it for the pin and was able to seat a bullet evenly OK. I tried several and the rounds chamber OK with just a little tightness when opening and closing the bolt. I am still trying to determine if the necks need to be reamed/thinned as every once in a while some of them are tighter when removing as the bolt turns.

[Parashooter]

If necks are too thick, you can feel the resistance when slowly moving the bolt the last 1/4" or so forward to chamber the round. (Remove the striker assembly first for safety and better sensitivity.) After extracting, you should be able to see evidence that the surface of the neck has been scraped as it enters the chamber neck. But - the standard way to check for thick necks is to try inserting one of your bullets in a case neck after firing with a load generating sufficient pressure to expand the case fully (squib loads won't do). If the bullet passes easily through the fired case neck, that indicates the neck is not too thick for bullets of that diameter or less.

Instead of inserting a feeler gauge between shellholder and case, it's not hard to simply remove some metal from either the top of the shellholder or the bottom of the die. Either can be accomplished with nothing more than a few sheets of 180-grit wet/dry abrasive paper on a hard surface like a kitchen counter top. Just apply enough light oil to keep the paper from clogging and rub the die bottom or shellholder top around on the paper in a circular motion for a few minutes, checking frequently with a good caliper. Try sizing a case every time you take off about .003". Stop when the case chambers easily. This is not difficult and requires very minimal investment. (Make a notch on the outside of the die mouth or shellholder top to remind yourself it's been customized and isn't for general use.)

If you haven't yet checked for press-spring (looking for a gap between die and shellholder when ram is at top of stroke with a case being sized), do so first to ensure you're not altering die or shellholder unnecessarily.

Attachment 63994

[ireload2]

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.

[browningautorifle]

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

They always have been. Lee is cheap so thus the problem.

[vintage hunter]

Lee is cheap so thus the problem.

I have no qualms with Lee dies. About half of the 50 or so die sets I own are Lee. Besides the occasional broken de-capping pin that can happen with any brand they've all worked flawlessly for me and the ammo loaded with them is just as uniform and accurate as that loaded with RCBS, Redding or Lyman. I had an RCBS FL size die that split from stem to stern once. Never had that happen to any of the cheap Lee's.

The Lee FL sizer measures 1.838" using the same .375 gauge diameter on a FL sized case

Unless you gotten the same results from multiple sets checking just one example isn't enough to rule out the possibility of an out of spec die.

I tried taking out the expander-decapper from the die and then put a 0.014" feeler gauge into the bottom of the shell holder and ran the case up again in the die after annealing it and the empty case then chambered easily into the rifle.

Sounds to me like his problem was a sloppy shell holder rather than the die.

[ireload2]

The original poster and at least a half dozen others on other forum over the last 15 years have complained about the Lee die for this caliber.
If you carefully read the original posters comments he stated that he had 2 sets of Lee dies with this problem. And then I checked mine and I find the same problem so it is not a single die. The problem is Lee does not always do his homework. Lee could at least buy a set of RCBS dies and a set of Reddings and a couple of 1891 Mausers before he determines his final die dimensions. Many or most Lee sizers are very close to the same dimensions as RCBS but the 7.65 Mauser made by Lee is wrong.
I have spent a good bit of time and money gathering all these dies and forming cases so I can measure the dies and my chambers. I am not willing to spend more money on another Lee die when I know that another brand is more dependable in this caliber.

Unless you gotten the same results from multiple sets checking just one example isn't enough to rule out the possibility of an out of spec die.

[ireload2]

There is a very easy way to measure your chamber NECK diameter.
Take one of your successfully formed cases and use a tapered punch or equivalent ( I have used a FMJ bullet too) to expand the case mouth .020 to .030 oversize - all you need is a trumpet shaped mouth. Take this case and chamber it. You will have to force the bolt handle forward a little to get the trumpet to squeeze down into the chamber neck.
Extract the case and measure the compressed edge of the trumpet. That will be your neck inside diameter. To get a major warm fuzzy you can measure it 3 or 4 times and get the same number.
I think you will find there is plenty of room for almost any brass on the planet.
I have several hundred US military SL-54 cases that I have formed for my rifles and it works fine in all of them.
Just be sure to anneal or you might get cracked necks within one or two reloads.

My cleanest 1891 Mauser measures .348 in the neck at the case mouth.
The ammo that I have loaded with the SL-54 military brass measures .338 to .340 over the case neck with .311 and .312 jacketed bullets.

Your use of the feeler gauge under the case head is good evidence of the Lee die interior being a little too long.
Send me a PM with your location. We might be pretty close. I am in the center of the state. I have access to a lathe and can cut off your die when I cut mine off.

I tried taking out the expander-decapper from the die and then put a 0.014" feeler gauge into the bottom of the shell holder and ran the case up again in the die after annealing it and the empty case then chambered easily into the rifle. I tried loading a bullet (Moyer's cast lead gas check 303 Brit 313 dia. 180 GR FP) into the case without primer/powder and the neck bulged on on side and was too tight. I then re-sized a case with the feeler guage with a whole in it for the pin and was able to seat a bullet evenly OK. I tried several and the rounds chamber OK with just a little tightness when opening and closing the bolt. I am still trying to determine if the necks need to be reamed/thinned as every once in a while some of them are tighter when removing as the bolt turns.

[browningautorifle]

I have no qualms with Lee dies.

You've been lucky then. I only have one if I can't get better. Then I replace it soonest. I have lots too. I've seen nothing but problems so I'd never use a Lee product as a regular item. None of it... One RCBS item failed? That's not bad.