Hello all. Let me start by saying I'm not a complete idiot when it comes to guns. My knowledge is limited to what I've been exposed to. My background is basic, 12 gauges, 22 rifles and pistols, and 45s. I recently purchased a ruger p89. I wanted 1 mainly cause I love to shoot anything and the ammo is alot cheaper than ammo for my 45s. I'm waiting to pick it up due to maryland's wait limit so I haven't shot it yet. Here is where my ignorance comes into play. When I look at 9mm ammo I see 9mm and 9mm luger. What is the difference between the 2? I don't want to get the wrong ammo and have sumthing wrong happen.please any help would be appreciated.