[John Rogers]

Several things no one has mentioned yet. First is chambering, .223 vs 5.56 can be an issue. For an accuracy gun .223 has a tighter chamber while 5.56 is the NATO size and can generally shoot anything. Second is shooting 22LR ammo which is really great as it saves a ton of $$$$$ and lets the wife and children also shoot. I would suggest a dedicated 22LR upper as the barrel twist in a "bolt adapter" type of conversion is wrong for rim fire ammo and you will be lucky to hit anything. There are some that can use the center fire trigger and some that do not. Third, I'd suggest buying a pre-built upper and use it to learn on. Saves time and stress and they generally work fine unless you plan to shoot wood chucks at 500 YDs or so. If you do that get one that has a full length rail on top so the optics are easier to mount. Last of all make sure the scope/red dot/etc you get has a mount that is sized for the rail and the scope is mounted correctly with a mount kit. I see at least one a month at our range that either come off or loose after a mag of shots as they are not mounted correctly.

Good luck as they are fun to shoot although I sold mine to support my black powder habit!