Replacing the barrel is not a big deal compared to others, but you need some basic tools, a upper receiver block to clamp the receiver, and a barrel nut wrench, if this is the only time you see yourself doing this, then find someone to do it for you, my charge would normally be 40-50 bucks, and that includes checking but not correcting the headspace, which is usually fine, but you never take it for granted. If you think you might do this more than once, then buy the tools, and learn the process, the AR is one of the most user friendly arms there is.