Hello,
I am new to the site. Am new to black rifles too! Just bought my first AR-15, the Colt M-4 (brand new)
Totally factory original. I know I may be in the wrong forum and apologize if I am, but what kind of accuracy should one expect from a stock rifle w/ stock sights? I am not an overly impressive iron sight shooter, but can hold my own. I shoot typically a 3"-4" group with my Marlin lever guns at 100 yds. Also, I know there are more accessories and upgrades to do for these rifles than you could fit in a thousasnd replies, but what are the real standards that almost everyone goes for? Excuse my ignorance and inexperience...I'll get there.
Thanks,
Lee

Basic rifle should shoot around 2 inch groups at 100 yards with out any difficulty.
MB

Welcome to the site and to black rifles.  A little less than a year ago I got the bug for an AR and started hanging out here to gather info.  This site is a great resource and you will find more information here than you can imagine.  As far as accessories, you are correct, there are more than can fit in a thousand replies, however, some of the "standards" include optical sights (red dots, reflex sights, scopes, etc.), picatinny rail handguards (so you have a place to mount all your new toys), replacement stocks, tactical lights, vertical hand grips, bipods, etc.  I would suggest taking a look at various picture threads on the boards so you can get an idea of what folks are using and how they are using some of these items.  Depending on the type of shooting you do some of the accessories might work well for you while others will just add weight and/or clutter.  Hope you enjoy your new rifle!

About 3 MOA or less with commercial FMJ. About 1.5 MOA or less with match rounds that your particular rifle likes.