I just got my first gun(XD9) about 6 months ago after shooting some and getting some guidance from a friend who is a very experienced shooter. Now a friend and his wife want to join me in the XD world. It is their first buy as well. They shot the XD .45 and loved it. They have NOT shot the 9mm and now are thinking of not trying it and going straight to the .45. I was trying to convince them to get the 9mm because of cost and less recoil. I'm no expert but, having read a lot and talked to several very experienced shooters, I am convinced the 9mm is the better choice. I am also telling them to at least try the 9mm before making a purchase. They talked to a local gun shop owner who told them the 9mm bullets will go through something or someone and could hit something on the other side of the intended target. They are buying the gun for home protection and plan to carry. My friend, who I mentioned before, told me that with the right bullet, the problem of shooting through something wouldn't be an issue. So, my question is, which is better for carry and home protection, the 9mm or the .45? If anyone can give me some info on the issue I would greatly appreciate it.