I know very little about rifles but am interested in purchasing an AR15 style rifle next year.  I'm not going to build.  I want to buy "off the shelf".  I'm looking for a SHTF type rifle that will be an accurate shooter that will probably live out it's life as a range toy but, God forbid, if the SHTF I can count on.   I'm more concerned about reliablity and being able to easily upgrade slowly than having the "latest and greatest".  I'm a "Ruger" or "Chevy" kind of guy rather than a $2k 1911 or