9mm Largo, Thoughts & Comments

[kenhwind]

To start off I have been loading the 9mm Largo for several years now using Dillon 9mm Luger Dies. Works just fine imo.
I have recently upgraded some of the Dillon dies to Redding Pro-Series because the Redding allows for much finer and more consistent bullet seating, especially with the Bullet Seating micrometer.

When I upgraded the .38 Super dies to Redding, I somehow ended up ordering an extra bullet seating die as well as a crimp die, probably because I ordered the standard die set.

So, now I figure that if I already have a seating die and a crimp die why not set up a 550 toolhead for the 9mm Largo. Curiosity led me to do an internet search as I looked for 9mm Largo dies. Some where it was mentioned that LEE list the .38 Super dies as compatible with the 9mm Largo, so I bought a LEE .38 Super sizing die.

Doesn't work. When checking the powder funnel flare with a fired case I thought maybe I better resize it so I do not get too much flare, I check and the bullet slides into the case. The .38 Super sizing die does not size a fired case enough to hold the bullet in the 9mm Largo case. Yes, I should have checked but the LEE die was cheap enough.

RCBS use to list, or I believe it was Huntington 9mm Largo dies but very expensive, the RCBS site lists the same 9mm dies for Luger, 9 x 21 and 9 x 23. When I started to load the Largo case I used, as posted the Luger dies.

Then I took the 9mm Luger Redding sizing die and made up a dummy round using that die and the .38 Super seating and crimp die, seemed to work out okay.

When viewing the case dimensions in the Speer Manual you realize that the 9mm Largo and .38 ACP are relatively close in size, but checking new brass with a caliper they are not that close.

Anyone else loading the 9mm Largo and have any more input.

 

[kenhwind]

After posting my OP and starting this thread yesterday I sized a few cases, 9mm Luger, 9mm Largo and .38 Super, did some measurements, and then measured some loaded dummy rounds up. Measurements or the loaded cases where relatively close or close enough for our purpose here.

Carbide pistol sizing dies are a compromise compared to all steel sizing dies I that the carbide ring must be small enough to resize the case mouth enough to hold the bullet. The 9mm carbide ring in my Redding die is smaller in diameter than the .38 Super carbide ring, also a Redding die, determined by resizing a 9mm case as well as the Largo case and measuring the diameter of it. Variations in case wall thickness are also a factor.

9mm Largo Load Data

RCBS and Sierra both have load data for the 9mm Largo.

Dies & Shell Holders

Hornady: Manufactures 9 x 23 dies, they list the same sizing die for 9mm Luger as well as 9 x 21. One might assume the 9 x 23 sizing die is the same also (not listed separately) considering the 9 x 23 and 9mm Luger case dimensions are essentially the same except for length.

Lee: “Lee .38 ACP/Super Pistol Die Set...
Note: This die set can also be used to load the .38 Colt NP, .38 S&W, 9mm Largo, and 9x23.”
My results proved negative using a Lee carbide .38 ACP/Super sizing die for the 9mm Largo as it does not size the case neck enough to hold a bullet. Redding .38 Super die does not either.

RCBS: Does not show or list any die information. Their site lists 9mm Luger, 9 x 21, 9 x 23 as one die set.

Sierra: 9mm Largo data under Remarks: “9x23 and 9mm Super Comp dies will work to load the Largo. The 9x21 dies will work if you back them out slightly.”
“Due to the deep extractor groove 9mm Shell plates and shell holders won’t work well.” They suggest using the Dillon #3 (.223) shell plate in the 550.

To load the 9mm Largo a 9mm Luger die set will work just fine imo. Due to the shorter length of the two the 9mm Luger seating and crimp die will need to be backed off some. This what I’ve done since I started loading the 9mm Largo.

This is now my 9mm Largo set up for the Dillon 550.
Dillon #3 shell plate for .223, #3 button.
Redding 9mm Luger carbide sizing die (Pro Series)
Redding .38 Super Pro Series seating die & crimp die
The dimension of loaded rounds is close enough that this set up is fine.

Conclusion, 9mm Largo dies are not necessarily needed because with all the Star pistols about someone would make them. Our Star AS is chamber for 9mm/38, 9mm Largo .38 ACP