Background: No experience with handguns yet. I have a beginner handgun safety class in two weeks. (I can hardly wait.) My primary goal at this point is home defense. Secondary goal is fun/hobby, I think I will enjoy shooting a lot. I may get to CC at some point when I have some experience. After reading lots of conflicting opinions here and other places concerning best caliber size for SD, I feel the best answer is "The largest caliber you can effectively use." Based on that, I'm currently thinking I'd like to get a Glock 22 with a .40 - 9mm conversion barrel. I'm thinking standard size Glock because of the HD - no CC emphasis and I love the idea of being able to shoot both .40 S&W (if I ever actually need it) and 9mm (since it's cheaper). Assuming I enjoy shooting as much as I think I will, I plan to get to the range two - three times a month. I want to get proficient, not just own a firearm to have a warm, fuzzy feeling. Question: Assuming I go with the Glock 22/conversion barrel, and keeping in mind my current experience level, would I be better off getting proficient/comfortable shooting .40 caliber first? If I did that I wouldn't have to spend the extra money for the conversion barrel up front and I assume when I did start shooting 9mm, it would be a cake walk. Or, would I be better off getting the conversion barrel immediately, get proficient with 9mm and at some point graduate to the .40?