RL 7 is what I use for my AR. I actually got the load info from my Nosler Reloading book. I use Hornady FMJBT and Nosler ballistic 55g.
To me it is a very clean powder. I don't have a cons and it ,meters very well with my Dillon 650.
In any event I have been using RL 7 for 7 plus years in my AR. I use it with Remington small rifle bench rest primers.
Give it a try I am sure you will like it.
I just picked up two 5lb jugs for $93 each.