Note: this was originally a reply in another thread, but I've received a dozen or more IMs about this, so I'm tacking it.  I will be updating it with additional pics and such as I am able.

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Okay, for the folks who haven't read all the data which explains WHY (and I'm not going to re-hash that here for the hundredth time; if you want the "why", read the tacked posts and all related links), I'm going to break it down.

First, a few points:

5.56 vs. .223 loads.  A "5.56" load means that the round is loaded to "military" pressures, which exceeds SAAMI's safe rating, and generally means from 120 fps (75-77gr bullets) to 200 fps (55gr bullets) additional muzzle velocity.  AR-based rifles with "5.56" or Wylde chambers can fire this ammo safely.  More muzzle velocity means a longer fragmentation range, so 5.56 loads are more desirable.  Having said that, you are almost always better off using a better-performing bullet in a .223 load than a lesser-performing bullet in a 5.56 load.

Generally, Open-Tip Match (OTM) bullets, also called Jacketed "Hollow-Point - Boat-Tail, Match" (JHP-BT Match) or Boat-Tail Hollow-Point, Match (BTHP Match) bullets, are the most reliable performers, as the consistancy in construction required for match accuracy also results in consistant terminal ballistic performance.


Okay, from best to worst:

1.  Loads using the Nosler 77gr or Hornady 75gr OTM bullet.  While these bullets may be slightly less accurate *in some rifles* than the Sierra MK, they offer better wounding capability.  These bullets maximize terminal ballistic performance AND they extend fragmentation range over other loads, and even provide *some* fragmentation range from 10" barrels.  These bullets require 1:8 or tighter twist barrels, though they may work in SOME 1:9 barrels.

- Hornady 75gr TAP (5.56 load)
- Hornady 75gr TAP or TAP-PD (.223 load)
- Black Hills loads with 75gr Hornady (.223)
- (no known factory load using the Nosler bullet)

2. Loads using the Sierra 77gr MK.  Like all MK bullets, this one doesn't start to yaw until it passes through several inches of flesh, resulting in a longer "neck" area of the wound profile, and thus being rated slightly lower than the Nosler or Hornady bullets.

- Black Hills Mk262 Mod1 (5.56, cosmetic seconds are available)
- Black Hills 77gr Sierra loads (.223)
- Federal 77gr Sierra (.223)


77grain MatchKing OTM in calibrated ballistic gelatin.  Note the long "neck" before fragmentation begins.


3. Loads using the 68gr Hornady OTM.  Note: barrel length needs to be 14.5" or longer; these will not have enough velocity to fragment from a 10" barrel and only a couple of yards from an 11.5" barrel.  1:9 or faster twist required.

- Hornady 68gr Match (.223)
- Black Hills 68gr Hornady (.223)

4. Loads using the 69gr Sierra MK.  Note: barrel length needs to be 14.5" or longer; these will not have enough velocity to fragment from a 10" barrel and only a couple of yards from an 11.5" barrel.  1:9 or faster twist required.

- Federal 69gr Sierra (.223)
- Black Hills 69gr Sierra (.223)

5. Loads using Trophy-Bonded Bear Claw bullets.  The 62gr performs a bit better than the 55gr, but the 62gr bullet is ONLY available in the LEO-only Federal Tactical line.  As a bonded-core bullet, these are excellent in situations with an intermediate barrier, and are the #1 performers when having to shoot through glass.    Note: these soft-point bullets have an exposed lead tip and cannot be rechambered more than a few times.  May not feed reliably in some rifles.

Federal Tactical 62gr TBBC (.223)
Federal Tactical 55gr TBBC (.223)
Federal Premium 55gr TBBC (.223)


6. Loads using the Winchester 64gr PowerPoint bullet.  Note: these soft-point bullets have an exposed lead tip and cannot be rechambered more than a few times.  May not feed reliably in some rifles.  1:10 or faster twist required.

- Winchester Supreme PowerPoint Plus (.223)
- Winchester Super-X PowerPoint (.223)


7.  M193-class ammo, 55gr FMJ-BT bullet.  True M193 ammo will be sealed at the bullet and primer, will have a crimped primer and bullet, and is a 5.56 pressure loading.  1:12 or faster twist required.

- Lake City M193 (genuine surplus M193; no longer available)
- Federal XM193 (seconds) or XM193PD (thirds)
- Winchester Q3131 (seconds)
- Winchester Q3131A (manufactured by IMI)
- IMI M193
- PMC, '98 and earlier
- South African M1Ax in battlepacks

8. M855-class ammo, 62gr FMJ-BT bullet with mild steel penetrator in the nose.  True M855 ammo will be sealed at the bullet and primer, will have a crimped primer and bullet, and is a 5.56 pressure loading.  1:10 or faster twist required.

- Lake City M855 (genuine surplus M855; no longer available)
- Winchester M855 (genuine surplus M855; no longer available)
- Federal XM855 (seconds) or XM855PD (thirds)
- Canadian IVI (genuine surplus M855; no longer available)
- British SS-109


This list should give you an idea of what is preferred, and in what order.  Obviously, many of the loads at the top are quite a bit more expensive than the loads further down (though the TBBC loads are by far the most expensive), but if you're looking just at performance, then this should be your guideline.

I might not have gotten every load out there, but you should be able figure it out if there's a similar load that I didn't mention.

ETA:

Loads To Avoid

Anything loaded with a varmint bullet; all varmint bullets in this caliber will underpenetrate from all guns.  This means NO VMax bullets (including TAP loads), NO Nosler/Combined Technologies "Ballistic Tip" bullets, and so on.  Varmint bullets were designed for animals no larger than 60 lbs., with the lighter bullets being designed for even smaller animals.  They are NOT combat bullets, regardless of marketing to the contrary.

Any frangible bullet load.  Frangible bullets are designed for short-range training, where shooting standard bullets at reactive steel targets would be (more of) a safety hazard.  Usually, they are made from powdered lead or tungsten alloy inside a gilding metal jacket.  They are designed to disintegrate when striking steel plates, but they are NOT designed to (nor do they accidentally) fragment in flesh.

"Armor Piercing" bullets.  It is incredibly unlikely that anyone outside of the military will be able to put their hands on a single round of TRUE AP ammo in 5.56, as M995 AP ammo is a speciality item that is rarely issued to anyone but SOCOM troops, and then only on SAW belts, and only when specially requested for a specific mission.  It is very expensive and in short supply, and it was designed primarily to disable equipment, NOT for wounding.  Since the bullet will not fragment, it is a poor performer with regards to wound profile.  This would hold true for any all-steel core or solid copper bullet as well.

-Troy

Quoted: I would add the 60gr Nosler Partition to your list

Yeah, it's virtually equal to the PowerPoint, and a good deer load as well.

-Troy

Quoted: What is the best possible round to be shot out of shorter barreled ARs (10.5-12.5" barrels)?

Did you read the list?

Quoted: Best to worst in what way? I see only one of the choices has a gel test. What is the basis for the ranking?

Did you read the intro?  The data on these various rounds have been discussed at length in dozens of threads here and many other well-known places on the net (www.tacticalforums.com, www.firearmstactical.com, etc.).  This is a CLIFF NOTES (read: quick overview).

-Troy

It wasn't very good, and Hornady discontinued it and sold it off cheap.  They have a newer version that's supposed to be much improved, thanks to the use of FBI-style testing during development.  Having said that, I haven't seen any independant test results.

-Troy

Quoted: Q3131 is next to last?  That's not very reassuring to those who use it for defensive purposes (read: I do).

At least it's on the list.  There are probably close to 100 factory 5.56/.223 loads on the market, but only the ones on the list are really suitable for combat/defensive use.

Keep in mind that the Hague conventions artificially limit most military ammo's effectiveness, on purpose.  That there are much better options available on the open market shouldn't be a huge surprise.

-Troy

Quoted: how about 55gr PSP bullets loaded to NATO velocities?

Penetration in some tests (bare gel, clothing) is adequate, but they don't do all that well in barrier tests.  The core isn't bonded to the jacket, so jacket seperation is a problem.  And it's fairly light; heavier SPs generally give better performance.

-Troy

Quoted: Troy, as always, you provide excellent info. We appreciate it!

You're very welcome, as is the positive feedback.  

Only question I have is in regards to the Sierra 77gr MK. It's ranked very high, yet it doesn't frag very quickly compared to some others. So, my question is, why is it ranked so high? Is it because it will fragment at longer ranges than many others (Like 68gr OTM and XM193), or is it the fragmenting and terminal performance is better despite it's "late start"? Maybe it's a combination of things?

It's a combo of both.  Despite being slow to yaw, it still disrupts a lot of tissue, and it fragments at lower velocities.  The latter means that it will still fragment (to 30-40 yards) from a 11.5" barrel (or to 25 or so yards from a 10" barrel), and considerably longer as barrel length increases.  Not many "fragmenting" rounds will fragment at *any* range from those short barrels.

The 68 and 69 gr have less fragmentation range (higher required velocity to fragment), won't fragment from 11.5" or shorter barrels, and disrupt less tissue in comparison.

-Troy

Approx. 2300-2350 fps impact velocity, which is the same as the 68gr Hornady.  And just like the heavier versions, the SMK takes longer to yaw (i.e., has a longer "neck" area of the wound profile) than the Hornady bullet.

-Troy

The 77 SMK, or, if it isn't stable enough from your 1:9, then likely the 69gr SMK.  Of course, every barrel is different, and yours may prefer the Nosler or Hornady versions, but chances are that the Sierra will be most accurate.

-Troy

Quoted: Great stuff, thanks!  Which of those OTM/MK rounds would be best for barrier and then human penetration?

Generally, OTM bullets aren't great barrier penetrators, but the heavier bullets do better than the ligher ones at retaining the ability to cause tissue damage after penetrating drywall or sheet steel.

The only "good" (and not necessarily great) ammo for barrier situations would be soft-points, particularly the Federal Tactical TBBC.  The 60gr Nosler Partition, the TAP Barrier, and even the 64gr PowerPoints are also pretty good.  None of these will make as large of a wound in bare tissue as a fragmenting bullet, but they perform better after passing through intermediate barriers.

.22" bullets are really too small for any one bullet to do everything well.  With such limited mass, you can't maximize performance in all areas at once.

-Troy

Quoted: How is 60 gr .223 TAP?

Please re-read the "Loads To Avoid" section.

-Troy

Quoted: Troy, great infomation. Have you worked with the 65 grain SGK bullet? Do you know of ant factory loads using this bullet?

No, and no.  The latter issue is why there is no data for the former.

-Troy

Quoted: Thanks.  When I consider the basic reason I have an AR, the more I realize I need something in a larger caliber.

Yes; it's a key reason why I'm so interested in the 6.8 SPC, and why I would like to see it adopted, or a new weapon created based on an all-new round developed using the same methodology that developed the SPC.

As part of the SPC development effort, a "from-scratch ideal cartridge" was created.  It would have used a 7mm bullet and a longer, fatter case.  It would have been shorter, smaller, and lighter than the .308, but with better capabilities at all ranges out to 1000 yards.  It would be usable in a short CQB carbine (controllable in full-auto), but also suitable for GPMG work and everything in between.  But it wouldn't fit in any existing weapon, so it has no chance in hell of ever being produced.  Still a good exercise, though.

-Troy

Quoted: Troy, can you advise the necessary velocity for the 75 & 77-gr BTHP bullets? Thanks again!

2200-2250 fps for the 75/77gr OTMs.

-Troy