Black Hills new and remanufactured ammo are both high in quality and perform the almost same and if you want accuracy, the Sierra 77-gr. Match King (MK262) is hard to beat, but they are struggling to keep up with demand. As (has been mentioned twice earlier in this post) another alternative is HSM (The Hunting Shack in Montana), who is a 30 year old company making accurate ammo as well.
HSM's version of the hard to find Black Hills load is called 223-11 and it's comparable in quality and accuracy (e.g. 10 shots producing .466" groups at 100 yards). Here's a little info on this MK262 load:
* 223-11: 2,700 + fps. Sierra MK262 77-gr. HPBT Match King that averaged .466" groups at HSM. Designed as a target load, but bullet also performs extremely well in tactical applications when a Mil-Spec Collet crimp is applied. (This is a better choice than M193, M855, or 60-gr. TAP, and is only superceded by Hornady's 75-gr. or Nosler's 77-gr. BTHP's.)
Another accurate load that's similar to Hornady's 75-gr. Match ammo is 223-17 (the load the HSM 5.56 Tactical was built upon) and here's a little info on it for consideration:
* 223-17: 2,700 fps = MOA or less groups depending on the shooter / equipment. New 223 case with standard Hornady 75-gr. BTHP T1 bullet. (This load was designed as Match Grade in quality. Can be used for both tactical or target purposes and is very similar to 223 TAP - using the same uncannelured T1 bullet.)