My M&P 15 TS came in cardboard box lined with an ultra thin layer of foam (not sure why they even bothered it is so thin). My dad's Sig M400 came in a slightly nicer cardboard box lined with styrofoam cut to the shape of the rifle (a very small step up from Smith & Wesson). Neither one seemed very sturdy for $1000+ rifles though when you consider the cases the M&P pistols or Glocks come in at half the price.

We both use Midway tactical rifle cases - the 43" versions - which are nice. I also have a 36" version for my M&P 15-22 which is snug even with the buttstock completely collapsed but it works.