The Ruger P95 uses ammunition that is developed in Germany. A dedicated agent will be happy to help you find more information on their official website.
No, they do not use the same magazines.
yes
Yes.
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.
.308
No, Centerfire ammunition is a cartridge-type ammunition, where muzzleloaders use separate bullet, powder, and priming charges.
You will have to have it checked out by a good gunsmith. There is more than one type of 7.65 ammunition.
44 magnum
Any explosive or ammunition that has not been accepted and type classified for use by the U.S. military
.380 auto ammunition can be a "ball" style bullet or metal jacketed hollow point.
As long as both the rifle and the revolver are chambered in .44 magnum you can use the same ammunition for both. I have a Henry rifle in .44 mag and a Ruger redhawk .44 mag and I use the same ammo for both. That's one of the nice things about that caliber.