Will the Real 9mm Luger Please Stand Up!

[dovehunter]

I was scrounging for brass at my club range the other day and ran across about a box worth of cases headstamped "S&W 9x19". I almost didn't pick them up thinking that they may have been some obscure caliber, although I also thought that would be strange coming from S&W. Luckily I found a few Winchester cases marked 9mm Luger and compared them with the S&W cases and the S&Ws were obviously also 9mm Luger. The reason I was confused is that my LEE 9mm Luger dies were also marked as being 9x21. When I got home I looked in my Lyman 49th edition loading manual and they showed 9mm Luger as also being referred to as 9x19. I know the Luger cases show up as being approximately 19 mm long when I measure them with my calipers. What then is the proper designation for 9mm Luger: 9x19 or 9x21?

[Jack]

I've always heard 9x19 as the metric designation for what we all refer to as the 9mm Luger - properly named the 9mm Parabellum.
en.wikipedia.org/wiki/9x19mm_Parabellum

[twomoons]

The 9x21 was a special caliber made up for the combat shooters to make a high capacity round with enough powder space to make maximum power standard. The 9x19 and the 9x21 are loaded with the same die set the same as 38/357 magnum. Many dies sets can be sued for different calibers and Lee in particular are kind of casual about marking their die sets. So My 32 H and R magnum dies are marked 32 h and R and 32 Long. My 38 apc set has a 38 S and W seater and so on. As long as the dies make ammo to spec the markings are not that critical and Lee saves money by not having to stamp each set with seperate markings. RCBS for example marks each die set to a specific caliber even is the 38 and 357 dies are the same.

380 APC = 9x17
9 Makarov= 9x18
9 Luger= 9x19
38 Super 9x21
9x21 brass is Super with a thicker web for higher pressure
9 Largo is also 9x21 But loaded to lower pressure than either 9x21 or Super.
9mm Bergman Bayard is about 9x20
9MM Roth Styer is also in theri somewhere...

This is all off the top of my head so there are probably more, wait , wait 9MM Italian is 9x19 if I remember right but loaded to 380 pressures... See where this is going?