Handgun rounds aren't that bad... but I just don't trust rifle rounds. I was next to my buddy, a long time, very skilled, shooter and loader, had a bad round that ended up causing a big KABOOM that literally ripped his upper apart and put a hole in his lower... not to mention i got in the neck with shrapnel... not enough to bleed but a lot closer to combat then I ever felt like being. It's amazing the damage one bad stuck round can cause.
At about $350/1000 for decent range rounds of 223, I just buy them. Back when I used to shoot competively, I made my own .38 super and .45 rounds. it was a lot of fun, but it takes committment to make it worthwhile.
I'd guess that was a case head separation, or that he had debris of some sort, and the AR wasn't completely in battery. (I'm only guessing, it could be other things. Using a handgun powder, loading reloads to 5.56 spec with used brass and non-crimped powders, etc.). Personally, I fear the handgun cartridges more, particularly .40 S&W. Handgun powders are much faster, and a double charge is more likely to go unnoticed.
At that price, for .223, it must be mil-spec bullets, nowadays. Most of those are frustratingly inaccurate, insufficient for prairie dog hunting or a Highpower match. If you're looking for something more accurate, spring for some M262 (it uses Sierra 77gr Open tip match bullets), or try some of the Black Hills BTHP or ballistic tip offerings.
If you're just 'plinking', M193 (55 Gr FMJ loaded to M193 mil-spec), or M855 (using 62 Gr SS109 bullets with steel cores) is just fine. I can only get about 2.5 moa out of M855, and 1-1.5 moa out of M193. But I can get 0.5 MOA out of matchkings and V-Maxes. It ruined the fun, for me, to use M193 or M855. M262 shoots well, enough for a 200 yard 'clean' in Highpower, but not as well as hand loads tuned to my AR(s).
Some cartridges I shoot, there is little choice, and I need to handload. 6mm BR Norma is one (although Lapua has a factory offering), and 9.3x62 (hunting) is another.
Sorry, I was sharing my preferences, not pushing them.