I do not know if this is the right forum ! Reloading ? I have reloaded for years (bolt rifles ) .I now have an AR .A friend who is a good reloader and bench rest shooter .He said the powder burn rate is very important (duh ,)because of the port that operates the rifle and the peak burn contributes to a harsh slam of the bolt or not enough soup to operate the system.I have 3 reloading manuals (2 with specific AR data) As long as I follow the recipe in the AR data what else could there be ?

“To account nothing of one's self, and to think always kindly and highly of others, this is great and perfect wisdom.”
― Thomas à Kempis, The Imitation of Christ