Test Specifications
Firearm Used: Star Super
Bbl. Length/Twist: 5.150" 1x16"

Test Components
Cases: Starline
Trim-to Length: .900"
Primers: Win Small Pistol

Remarks:
Although virtually unheard of until recently, the 9mm Largo is not a new cartridge. Developed in the early 1900's as a military pistol cartridge, it was adopted by the Danish (Model 1910) and the Spanish (Star and Astra) military. Also known as a 9mm Bayard, Bermann, Bergmann-Bayard, Bayard Long, Danish and 9 x 23, the Largo is almost exactly like the popular 38 Super except being rimless and having a deeper extractor groove.

9mm Luger, 9x21, 9x23 and 38 Super dies will all work to load the Largo. The surplus ammo available is all berdan primed, but for the reloader, Starline Brass makes cases just for the 9mm Largo.

Due to the deeper extractor groove, 9mm shell plates and shell holders don't work well. In the Dillon, we found the #3 shell plate (.222, .223, etc.) with #3 buttons worked well on the Model 550.

One thing we noticed in the Star we tested and others we examined was the diameter of the firing pin hole being exceptionally large allowing the primer to flow back into the opening. We suggest using primers with hard cups such as Winchester or CCI to help prevent that.