6.8 Mags
PRI - solid welded not spot welded, most consistent OAL. Loads reliably to 2.3 OAL, strong, best mag made for loading up to 2.3 OAL but spendy.
Barrett - Once considered one of the best, great mag but limits loading to 2.7 OAL. Fine for factory ammo but not so good for reloaders. Reliable just short OAL
ASC - The new standard in spot weld construction steel mags. Loads up to 2.316 OAL, some do load slightly shorter in the 2.31 range. Good followers and reliable.
CPD - This mag was redesigned a year or so ago, inconsistent OAL 2.29 to 2.31 feeds factory ammo just fine but their are better choices for reloaders.
DSA, AR Stoner, PSA all hit or miss in my book, some work good others need feed lip or follower help.
5.56 mags will bulge after 5 to 8 rounds depending on follower, also feed lip angle can be hit or miss in some rifles.