If you are talking about accuracy, and you are a reloader......., the Sierra Varminter 63 gr. Semi Point #1370 in front of 24.5 grains of 2230 is the most accurate combination I have ever found
bar none!!I shoot this load in my 1:7 M4 & 1:9 MT6731 AR's and in my 1:12 Rem. 700 LVSF
Extremely accurate in all three..., and very explosive on critters!!
I think the biggest reason it is so accurate in the AR's is that
the "Semi-pointed" bullet has a faster tapering Ogive (rounder nose design) which allows you to have the bullet seated to almost touching the rifling lands when the round is in full battery, but still have a short enough OAL to fit in, and feed properly from the magazine!
Without exception....., all other .223/.224 bullet weights & shapes I've tried do not come any where near close enough to the lands when chambered to produce any real accuracy when seated short enough to fit into a AR mag!!
As for factory loads..., Ive never found anything that you could call "extremely" accurate!!
Although I have heard a lot of good stuff about Blackhills Ammo!!