Question on 20" AR15s????

[DD977GM2]

For those of you who have a 20" AR, how do you like it? If its 1/7 twist rate, do you get better accuracy out of 77 gr ammunition? Do you have a set up like a designated marksmen rifle? Did you throw a non magnifying sight like Aimpoint or Eotech on it or throw an ACOG on it or a regular tactical scope or hunting scope on it? Let me know how you really feel about them!!!!!

I traded for my first ever 20" AR and I have always had 16" and figured if SHTF I wouldnt engage bad guys out any further then 300 to 500 yards and felt confident with 16" ARs to get the job done.

Here is a pic of it and I am anxious to get out and throw some rounds down range this weekend. Pkum Crazy lower and unknown Upper but has 1/7 and 5.56 on barrel.