I am 21-year old college student residing in Georgia and am interesting in getting a reliable, effective handgun for personal defense. I didn't grow up around guns, no one in my family owns one, so I don't know too much about them other than what I've read. Does anyone have recommendations for a first time buyer? As far as caliber goes, I know some of the popular types are 9mm, .40 S&W and .45, and have read up on the debate between them. I think I'm leaning towards .40 S&W, because it appears they have more stopping power, and I'd rather I be able to drop the average assailant in one shot. If I'm not mistaken, 9mms tend to go through the target, right? And I'm worried that a .45 might a be a little unwieldly for my first gun. I'm pretty sure I don't want a compact, I don't need to conceal it on my person as I'd have it in my car or apartment. My price range is around $600 dollars. Can I find comparable quality guns outside of the major players like Glock, HK, Colt, and Beretta? I'd appreciate anyone's recommendations.