Barrel Twist
 

I've noticed all my books say the 9mm likes about a 10:1 twist. Pretty tight compared to other pistol rounds. Has anyone measured the Luger twist rate? Did it change over the years?

I tried with a cleaning rod, a tight patch, and a soft pencil. Not very scientific but seem to be getting a bit less than 10:1. Maybe even 8.5:1???

Anyone else?

FN

FN:

According to the DWM pre-WWI publication " The Parabellum Automatic Pistol", (the English version of "Die Selbstlade-Pistole "Parabellum"), the rate is the same for both the 7.65mm and 9mm applications, that being one turn in 9.84 inches (or 250 mm).

You might also want to know, that the original powder charge was also exactly the same, for both the 7.65mm and 9mm, at 5.4 grs.

My Mauser manual of the 1930s "Original Mauser Parabellum Selbstlade-Pistole" lists the exact same turn rate, at 250 mm, for both calibers.

The rates didn't change during the period of the original German production.

Sieger