Thanks for starting the same thread I was about to. I too am new to AR's and have also recently purchased a DD M4 V7 after doing heaps of research.
Today was my first opportunity to put some rounds through it. Shooting PMC .223 55 grain FMJ. 20 round magpul mags. I had multiple 'failure to load' where the round would partially seat and the bolt would not fully close. I cleared removed the round and reset with three different magazines and still had the problem. The charging handle feels loose as well. The gun goes to the smith tomorrow after only putting 40 rounds down range.
Hope you have better times.