I want to go pick up an 870, but, I have never owned a shotgun, and have only shot them a handful of times so I want to ask you guys some questions before I pick one up. Basically I'll have it for home defense, but would love to take it to a range and shoot trap with the guys from time to time. I don't really understand the terminology of 18" choke, 26-28" vent barrel with a modified choke. I have no idea what they are talking about. So if someone could break it down, and even make suggestions, I'd appreciate it.