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9mm: Luger vs. Largo

Discussion in 'Handloading and Reloading' started by Col. Harrumph, Aug 12, 2018 at 12:39 PM.

  1. Col. Harrumph

    Col. Harrumph Member

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    I’ve got a set of RCBS 9mm Luger dies that I’ve also been using to load 9mm Largo, and rather than reset the dies every time I switch between them I’d like to find a spacer washer that I could put under the lock rings when loading the longer round. This is the same sort of spacer that’s usually supplied with die sets that double between .38 Spl & .357 Mag, or between .44 Spl & .44 Mag.

    I’ve measured my own fired case lengths and the Largos average about 0.15 inch longer than the Lugers I’ve collected: Starline’s 9mm Largo cases run 0.892” after firing, and Winchester’s Lugers run 0.741”. So it logically I need do find a washer that’s 150 thou thick, assuming I load the same bullet in each, which I do: Berry’s 124gr plated round nose. (Both pistols are range toys, not serious tools.)

    I measured the spacer supplied with my RCBS .38/.357 dies and at 0.127” thick it’s way over the 1/10 inch you’d expect from knowing that the Magnum case was specified to be a tenth inch longer than the Special.

    So what gives? The (former) engineer in me says that extra 27 thou is going to clobber any precision I might pretend to (never mind using bullets with different ogives). Am I obsessing about the trivial, or missing something important?
     
  2. ray15

    ray15 Member

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    Measuring fired .357 mag and 38 special cases I've got on hand shows 0.133" - 0.136" difference in length. .357 mag is 1.270-1.290" and 38 special 1.135-1.155" by SAAMI specs. I'm not sure why the spacer isn't 0.135" on the button. Maybe they intend to put a heavier crimp on the .357s.
     
  3. Blue68f100

    Blue68f100 Member

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    You can use a set of shim's and adj as needed. The last time I bought some they were cheap off Amazon. If I recall they were only $6 for the set. Starting with 0.001"-0.125", a total of 25 shims.
     
  4. Jim Watson

    Jim Watson Member

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    Given a .127" washer and wanting a .150" spacer, I would start measuring stuff and figure on cutting a shim out of something convenient near .023" thick.
    A couple of items at random, a Panera plastic coupon is .029", a piece of glossy card stock from some sort of mailing is .020". I bet either would be close enough, especially considering that I use a Lee CFC with easy adjustment of crimp.
     
  5. Blue68f100

    Blue68f100 Member

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  6. ArchAngelCD

    ArchAngelCD Member

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  7. Walkalong

    Walkalong Moderator

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    Shims or a second sizer, both will work. I'd go for the second sizer. Actually, I would probably go for a second set of dies eventually, like I did for .38 Spl/.357 and .44 Spl/.Mag.
     
    MI2600 and cfullgraf like this.
  8. ArchAngelCD

    ArchAngelCD Member

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    I did the same, I waited for a sale and bought a second set of dies. I bought a set of .357 Magnum only dies on closeout VERY cheap!
     
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  9. cfullgraf

    cfullgraf Member

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    I'm also in the "get a second set of dies" camp. I've done that with 38 Special/357 Magnum, 44 Special/44 Magnum, and 327 Fed Mag/32 H&R Mag/32 S&WL.

    I'll admit, that adding a progressive press in my reloading room precipitated that decision as I was still using the RCBS spacer on my single stage press.

    But, an alternative is to find a friend with a surface grinder and make a spacer. If you can come with a piece to start with (2 RCBS spacers cut to 1/2 thickness needed or maybe a steel die lock ring with the threads drilled out) a machine shop may not charge much to cut it down to size on a surface grinder.
     
  10. ray15

    ray15 Member

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    I've not used anything but Starline brass in .357 magnum and it's so much thicker than all my 38 special brass I need a different sizing die. The standard Lee 38/357 sizing die isn't small enough for my 38 brass; on a tip from Walkalong I bought a RCBS one and it's smaller. That gives me proper case mouth tension on the 38 brass but you can't hardly pass the Starline .357 brass though it without lube, and it's clearly overworking the brass. The standard Lee sizing die is perfect for the .357 brass.

    I think in all I've got three Lee four-die 38 sets plus the RCBS sizer and a Lee undersize sizer for .355-.356 bullets in 38. At less than 40 bucks I buy as many as I like.
     
  11. Stumper

    Stumper Member

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    FWIW, Bulk washers tend to vary in thickness. I took my calipers to the hardware store and simply checked and selected what I needed for spacers.
     
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