From the Ruger website: What type of ammunition should I use in my Ruger 9mm pistol? The Ruger 9mm pistols are chambered for the 9x19mm NATO Parabellum (9mm Luger) cartridge, compatible with the U.S. and foreign military or commercial 9x19mm loads manufactured in accordance with NATO, U.S., SAAMI, or CIP standards, including high-velocity, subsonic, tracer, hollow point, ammunition loaded in aluminum, steel, or brass cartridge cases, +P and +P+ ammunition.
From the Ruger website: What type of ammunition should I use in my Ruger 9mm pistol? The Ruger 9mm pistols are chambered for the 9x19mm NATO Parabellum (9mm Luger) cartridge, compatible with the U.S. and foreign military or commercial 9x19mm loads manufactured in accordance with NATO, U.S., SAAMI, or CIP standards, including high-velocity, subsonic, tracer, hollow point, ammunition loaded in aluminum, steel, or brass cartridge cases, +P and +P+ ammunition.
Fifteen rounds of 9mm.
Without question, the .22.
Colt has never made a 9mm ruger combat commander
Yes, these models exist, mainly due to the fact that the Czech Republic joined NATO in 1999, they had to use the 9mm rounds because it was standard issue to pistols used by NATO members. There are other varieties for commercial use, for example, the pistols offered by CZ-USA.
None to really speak of. They are, for the most part, one and the same. The 9mm NATO is merely a variant of the 9mm Luger loaded for military specifications.
Which one?
Ruger never made a model called the P38.
The Glock 17 (full-size 9mm) holds 17 rounds in a factory magazine. The Glock 19 (compact 9mm) holds 15 rounds in a factory magazine. The Glock 26 (teeny-tiny 9mm) holds 10 rounds in a factory magazine. The Glock 17L/34 (competition) also holds 17 rounds.
You can request a manual for free at Ruger's web site.
Contact Ruger Customer Service through their website.