I have also had good luck with TargetSports, 9mm, .45 and 5.56mm.
I've shot thousands of rounds of .223 by S&B (9 & 45 too). However, it has a steel core (attracts a magnet) so not optimal for my local indoor range.
Check out bonefronggunclub.com for higher end 5.56 (Gold Dot, MK318 etc.). Also similar products in 9mm & .45.
Once upon a time G&R Tac offered good deals on Black Hills 5.56mm, but it's been awhile (well a decade or so) but it was good M193.
I've never bought or fired and ComBloc 5.56 (or any other caliber) ammo. Beyond a spam can of PRC 7.62x39 bought at the Pomona Fair Grounds gunshots in California in the 80's. Too its credit, it fire well last year in an AKM type, which I first cleaned with boiling water. Would not do that in my ARs.
In today's political climate, but early and often. Max out your gun budget and climate controlled storage. It'll probably never been cheaper.