I'm a typical/civilian user that wants to put back some 5.56 mm (or possibly .223, depending) for self-defense /
home-defense purposes.  And yeah-- I've already done some searching around (here, YouTube, etc.) and seen many
comparisons, tests, product reviews, opinions, allegations, recriminations, etc., etc.

Also-- old options become unavailable/expensive/go out of stock; and newer/better options come along...
so before dropping my $$$'s, just wanted to ask the experts here & see if there's anything I may have
missed.  Top defensive ammo possibilities I'm looking at now:

Speer Gold-Dot GDSP 55 gr .223  (? "#1 choice for law enforcement" ?)
IMI 5.56mm 77 Grain SMK OTM LR MOD-1 Razorcore   (Mk262 clone)
Black Hills 5.56mm NATO 50 / 62 Grain Barnes TSX Hollow Point  (*seems a bit expensive/hard to find)
Hornady Critical Defense FTX 55 gr  .223

Any problems with these?  Anything else I should consider, that's actually available to civilian shooters?
(ideally I'd like it no more than $1-$1.50/rd max).  Also, I never anticipate doing any sort of competitive shooting, so
grinding out another .25 MOA of accuracy isn't relevant to my needs ('minute of man').

Thanks in advance for your input,

SD

Check Target Sport USA, SGAmmo and Bonefrog

Example:
Fed Tac bonded

Federal Fusion is a good round. Bonded soft point

https://ammoseek.com/ammo/223-remington/Federal-rifle-62grains

What size AR?

I'd prefer buying something for "general" use -- so nice if it maintains good
terminal performance out of a short barrel (~10.5").

.84 cents a round; .96 cents a round and $1.00 a round respectively

Sellier & Bellot - 5.56x45mm - 77 Grain - HPBT - 1000 Rounds

5.56 x 45, 77gr, Sierra MatchKing Hollow Point, IMI Brass, 500 rounds, Razor Core Mod 1 (MK262 Type)

500 Round Case - 5.56mm 77 Grain SMK OTM LR MOD-1 Razorcore IMI Ammo

All of the aforementioned are quality loadings. We can argue in circles over shades of devastating, but in bottom-line terms all of those bullets are going to have serious effect on target at justifiable HD distances.

I have 77gr TMK loaded to 5.56 pressure in my HD rifle and 62gr TBBC in case of communist Russian zombie invasion where barrier performance could be a factor.

That's pretty much been my conclusion as well, after looking at 5.56 ammo at different times
over the years.  Even the plain vanilla 55 gr ball ammo is devastatingly effective,
when fired out of barrels allowing sufficient velocity.  [granted, police/HD use can
have requirements that are generally of little concern to the military, e.g., over-penetration]

From what media reports are openly available, the IMI Mk262 variant ("Razorcore") is being used
by Israeli military/police units, to good effect; I'm not sure how common this type of round is
with police in the USA.

And of course for civilian use, there's the option of soft-point bullets intentionally designed for
expansion on impact (e.g., Speer option listed above).

Any of your choices are fine. As others have said, we can argue in circles over the minutia of differences between .223 and 5.56 loads and never reach a consensus.

Personally I have 62gr. Federal Fusion in my ready gear, backed up with M193. I'm not willing to spend $1-$2 a round to buy "better" ammunition when what I already have is adequate. Unless I run across a smoking deal on some of the premium stuff, my next 5.56 purchase will just be quality M193.

IMI MK262 is legit. Plenty accurate, and affordable. No reason you shouldn't be stacking deep. My LGS has 5.56 BH 62 TSX. I picked up 400 rounds of it to try out. In the end I stuck with 77g IMI in my 14.5/16". I also have a completely different loadout. A 20" that I use M193 in. Super fun to shoot, and extremely effective against soft targets.

edit: You might look into graindhardammo. They have a 62g controlled chaos round that i've seen absolutely demolish pigs. I'm talking DRT w/ decent shot placement. I believe it is 700 ish for 500 rounds.