I have now read the ammo oracle site twice and there are still a few points I am unclear on.  Based on what I have been reading, it would appear that the most catastrophic and effective result using 5.56 probably won't come from conventional expansion (because the bullet is just too small) but rather from yawing and the resulting fragmentation that yawing will produce when it hits deep tissue.  To get that effect reliably, it would seem that you want a round that has most of it's mass/weight in it's base, has a thin copper jacket (that eliminates Wolf ammo), and is traveling at least 2700 fps at impact.  Is my understanding on these points correct so far?  If so then why would the heavier 75gr and up rounds like the Sierra Match King be considered effective when they are barely going above 2700 fps at the muzzle? Wouldn't their primary function be expansion and not fragmentation or am I missing something?  

What I am looking for is the most effective and devastating .223 round for use in my AR (which has a chrome lined 16" barrel with a 1:7 twist) at a range of 5-200yards. If understand the info on ammo oracle, that would seem to be M193 ammo?

Thanks in advance for the feedback!

If you are looking for expansion, you need to look elsewhere than FMJ's and match open tip bullets. Neither one are designed to expand, it's not there intended purpose.

I don't know of any .22 caliber bullets that will reliably expand in a target the size of a human, maybe the 55 and 60 grain soft point hunting bullets. I really doubt varmint bullets will expand since, I believe they are light jacketed and meant to come apart.

Something that occurs to me is that a .223 caliber bullet that expands is only going to expand to a little larger than .223, so you don't get that much effect from it just a single, slightly larger wound channel as opposed to a bullet that fragments and produces numerous smaller wound channels.

Not totally sure, but I believe the Hornady and Sierra heavy open tip bullets fragment at lower velicities than M193 or M855 because their jackets are even thinner, and their longer length makes them less able to stay together when yawing.

Becasue the fragmentation threshold is lower for the OTM bullets.  The long length results in a fast yaw with lots of pressure exerted on a very thin jacket which cannot contain the pressures.  You are looking at the 2700 fps figure which is for M193 and M855 ammo only.  It applies to no other bullets.

Sounds like you have a similar issue to me and a similar rifle. Our questions seems similar too so I will watch this thread too for the answer.
My Topic is "Commercially Available replacement for M193?" in case you want to follow my topic too. Hopefully we will get to the bottom of this ;)

The 2700/2500 fps threshold only applies to the M193/M855 rounds.  Outside fo that, the velocities will be different.  The heavy Mk262 fragments at a lower velocity due to the longer length of the projo.  the LE type rounds and hunting/varmint rounds will have different standards as well.  DocGKR has quite a few suggestions of non-.mil ammo that does well on terminal ballistics in the 5.56.
ETA:  ISTR that the threshold for the 75/77 loading is possibly as low as around 2100/2200 fps, but I might have that wrong.

If you don’t think that M193 is good enough then get a .308.

The 5.56 is a good military cartridge. It’s lightweight and has low recoil plus it does a pretty good job of putting someone on their back if it fragments. If it doesn’t fragment then all bets are off but this is usually only an issue out past 100-200 yards. And, a .22 hole might not stop someone instantly but I’ll bet it’s gonna make it hard for them to deliver accurate 200 yard return fire.

So I feel very well armed with either my AR-15 or Mini-14, especially knowing that if the first round doesn’t stop my target then it has 29 little friends just waiting to help put the bad guy down. I’m even fine with commercial .223 although I’ll admit I prefer the full powered 5.56 military ammo.

But when someone is trying to wring out the last drop of performance from their ammo it’s a sign that they feel under gunned. Think about it… How many 12 gauge shotgun users are bothered by the fact that there might be a brand of slug out there with 5% more stopping power than the slugs they have loaded? People with 9mm pistols try to find the perfect ammo in an attempt to get adequate stopping power, people with 44 Magnums just load a decent hollowpoint and feel confident.

If you are really trying to find the absolute best ammo then you probably don’t feel that the normal stuff is adequate and that means you might be best served by moving up a size.

Of course if you think the normal .223 is acceptable and the full powered 5.56 is pretty good, but just want to know if there’s anything even better than just disregard my post…

If you go with something like the Winchester 64 grain Power Point you will get expansion and not fragmentation. Twice the original diameter is considered good expansion in a deer bullet. So you are looking at up to a .448 inches.  Even if it only does 1.5x in a person you still get .336 which is not too bad.  But this bullet was really made for hunting deer with more potent cartridges like the 220 Swift and 22-250. So even 1.5x could be optimistic.

The real problem with expanding ammo is cost.  Unless you reload, you are looking at costs of $10-15 for 20 rounds.

All this technological bull is probably confusing DHB, all the explanation from "experts' and no one has answered his question.

"What I am looking for is the most effective and devastating .223 round for use in my AR (which has a chrome lined 16" barrel with a 1:7 twist) at a range of 5-200yards."

Get off it, if you can't answer the question, then save your reply!

Fragmentation is better than expansion in .223/5.56

Quoted: If you don’t think that M193 is good enough then get a .308. The 5.56 is a good military cartridge. It’s lightweight and has low recoil plus it does a pretty good job of putting someone on their back if it fragments. If it doesn’t fragment then all bets are off but this is usually only an issue out past 100-200 yards. And, a .22 hole might not stop someone instantly but I’ll bet it’s gonna make it hard for them to deliver accurate 200 yard return fire. So I feel very well armed with either my AR-15 or Mini-14, especially knowing that if the first round doesn’t stop my target then it has 29 little friends just waiting to help put the bad guy down. I’m even fine with commercial .223 although I’ll admit I prefer the full powered 5.56 military ammo. But when someone is trying to wring out the last drop of performance from their ammo it’s a sign that they feel under gunned. Think about it… How many 12 gauge shotgun users are bothered by the fact that there might be a brand of slug out there with 5% more stopping power than the slugs they have loaded? People with 9mm pistols try to find the perfect ammo in an attempt to get adequate stopping power, people with 44 Magnums just load a decent hollowpoint and feel confident. If you are really trying to find the absolute best ammo then you probably don’t feel that the normal stuff is adequate and that means you might be best served by moving up a size. Of course if you think the normal .223 is acceptable and the full powered 5.56 is pretty good, but just want to know if there’s anything even better than just disregard my post…

Good answer. Made me think.

Quoted: Get off it, if you can't answer the question, then save your reply! Fragmentation is better than expansion in .223/5.56

Gee you must be a frustrated middle manager type who suffers from severe linear thought processes.  
There were several questions/mistatements in the original post.  The following posts were made to clear up some of the misconceptions.
Let DHB be a big boy and wipe his own butt if he has a problem understanding the info provided.  All he has to do is ask if he is confused.

Quoted: All this technological bull is probably confusing DHB, all the explanation from "experts' and no one has answered his question. "What I am looking for is the most effective and devastating .223 round for use in my AR (which has a chrome lined 16" barrel with a 1:7 twist) at a range of 5-200yards." Get off it, if you can't answer the question, then save your reply! Fragmentation is better than expansion in .223/5.56

If he wants the most devastating commercially available round in .223 pressure then he wants 75gr BlackHills or 75gr Hornady TAP.

Remington's  55 gr. PSP (pointed soft point) both expands and fragments. The only thing left is the jacket after expanding/fragging. It leaves a larger cavity than xm193 in wet newsprint but doesn't penatrate qite as deep.

To the best of my knowledge, here are your options.

The most effective round that you could buy is either the .223 pressure 75 gr black hills or TAP, if you are willing to reload, then you can make NATO pressure loads of either of those. These bullets fragment all the way down to 2300 fps, so from a 16" barrel you get out to about 150 yards with commercial stuff, and a little over 175 with the NATO stuff. If you are a LEO (or know one) then you can get the NATO pressure stuff straight from Hornady.

ETA: Why isn't it important for the round to perfrom at less than 5 yards? Were you trained by Chuck Norris or something?

ETA: With M193 you'll only get out to about 105 yards, and with M855, only about 90. (but these are still both far enough for realistic self defense shootings. FWIW)

Quoted: If you go with something like the Winchester 64 grain Power Point you will get expansion and not fragmentation. Twice the original diameter is considered good expansion in a deer bullet. So you are looking at up to a .448 inches.  Even if it only does 1.5x in a person you still get .336 which is not too bad.  But this bullet was really made for hunting deer with more potent cartridges like the 220 Swift and 22-250. So even 1.5x could be optimistic. The real problem with expanding ammo is cost.  Unless you reload, you are looking at costs of $10-15 for 20 rounds.

There was a very interesting article by Mas Ayoob in a recent magazine about a guy using that ammo over in Iraq or Afghaniland, I can't remember which. Suffice to say, the 64gr. expanding stuff worked.

Excellent responses everyone and thanks to each and every one of you for responding.  I have to admit that for a while I was beginning to feel that some may not have really understood my post.  Don't get me wrong though because I do appreciate those responses as they were providing great info.  What I really was looking for was an answer to the following:
Q - Was my understanding of fragmentation being better than expansion (for defense) in .223 correct?
A - A definite yes

Q - Was my understanding of the main factors involved in acheiving reliable fragmentation correct (most of it's mass/weight in it's base, has a thin copper jacket, and is traveling at least 2700 fps at impact)?
A - Yes except for the 2700 fps part.  That only seems to apply for M193 and M855 sized bullets/loads.

Q - Why would the heavier 75gr and up rounds like the Sierra Match King be considered effective when they are barely going above 2700 fps at the muzzle?
A - Because of the length of these bullets and their thin copper jacket, they yaw and fragment at much lower velocities than M193/M855 ammo. It would also seem that upon fragmentation that their higher mass makes for a more impressive and devastating wound cavity.

Q - The most effective and devastating .223 round for use in my AR (which has a chrome lined 16" barrel with a 1:7 twist) at a range of 5-200yards?
A - It would seem that this would be the 75-77 gr. Black Hills or TAP type ammo.  

Please let me know if I am wrong for any of the points above.  

NOTE FOR PanzerMK7: I wish I had training by Chuck!  I didn't ask about 0-5 yards because I figured that at this close of a range that any round would probably fragement reliably. That and I was wondering if anyone might wonder why and ask. huban:
Thanks again everyone!

Quoted: Q - Was my understanding of fragmentation being better than expansion (for defense) in .223 correct? A - A definite yes

For FMJ and OTM bullets I think this correct.  Varmint bullets lack penetration and are another story.

I'd really like to see a study that compares expanding bullets with FMJ and OTM at longer range with lower velocity.  Both FMJ and OTM bullets need velocity to fragment. But, an expanding bullet will expand at velocities far lower than FMJ or OTM will fragment.  I would expect the expanding bullets to out perform FMJ or OTM once you get past fragmentation range.

Quoted: Quoted: Q - Was my understanding of fragmentation being better than expansion (for defense) in .223 correct? A - A definite yes For FMJ and OTM bullets I think this correct.  Varmint bullets lack penetration and are another story. I'd really like to see a study that compares expanding bullets with FMJ and OTM at longer range with lower velocity.  Both FMJ and OTM bullets need velocity to fragment. But, an expanding bullet will expand at velocities far lower than FMJ or OTM will fragment.  I would expect the expanding bullets to out perform FMJ or OTM once you get past fragmentation range.

I am leaning to this line of thought as well.  Remember, the reason a large and widely distributed database of expanding bullets terminal effects on humans isn't available is the military has never used expanding bullets.  Within LE circles I would guess such a database exists, but it's not distributed for the masses.  I've always wondered if the military weren't constrained by abiding to the Hague Convention rules, if they would have elected to equip forces with expanding softpoint or some other controlled expansion design (e.g., all copper DPX) rather than FMJ-BT or even OTM.

One other point to ponder:  where intermediate barriers are involved, I believe controlled expansion designs offer much better terminal ballistics than either FMJ or OTM.

The 5.56 loads give about 50 yards more fragmentation range not 25 as stated earlier.

A bullet that does not fragment does not just mamke a .22 hole as it still yaws and presents a 1" wide wound channel as it passes 90 deg.

Many soft points still fragment instead of just mushrooming in .223 such as the 64 grain Power Point.  Soft point bullets like the Power Point also have a horrible BC and shed velocity very quickly and drop like a stone relatively speaking.  I would not choose a bullet that gets blown around by the wind and drops like a stone for long range shooting.

The only .223 barrier round that offers sufficent penetration after passing through intermediate barriers is the Federal Trophy Bonded Bear Claw as loaded in their LE Tactical line in 55 and 62 grain or the Premium hunting line in 55 grain.  These bonded bullets DO NOT fragemtn even at close range and offer much less tissue disruption than OTM bullets.

The greaer mass of the 75 grain ammo is not the cause of the greater wound channel, it actually has a greater % of fragmentation than the lighter rounds, not just larger fragments.

Moving up to a .308 is not an option for people using the 5.56 weapons.  The ammo is more expensive, magazine capacity is reduced, reliability is reduced, suppressor options suck, follow up shots are slower etc.  It is foolish to try to reccomend "just move up to .308" when the 5.56 systems offer certain features people are using them for which disappear in the larger calibers.  Sure 5.56 needs all the help it can get... I would use the same care in selecting ammunition for a .308 as I would want the best available combination of accuracy, terminal effectiveness, barrier penetration, etc.  The same goes for 9mm as well as .45 cal.  Why would someone NOT use the best available ammunition, optics, suppressors, barrels or any other equipment when it is readily available?

Quoted: Soft point bullets like the Power Point also have a horrible BC

Not really.  I looked up the trajectory on Winchester's site and used the Norma Ballistics calculator to figure out the BC. It's about .25 Seirra lists the BC of a 55 grain FMJBT as between .235 and .272 depending on the velocity.  The the Win PP's BC is not great but I wouldn't go so far as to call it horrible.

I ran the numbers after dropping Win's figure of 3021 fps down to 2770 to account for shorter barrel. I used a 200 yard zeroed. It drops a foot at 310 yards and is going 1745fps and has 434 ft lbs.  At 370 yards it's down 2 feet, going 1591 fps and has 360 ft lbs.  At 1500 fps it will expand, how much I can't say. It still has about the same energy as a 9mm at the muzzle.

In comparison the BC of 75 grain OTM is .395 the 68 grain is .355 and .22lr lead round nose 40 grain has a BC of .150

for a .223 the 64 grain PP does not have a good BC for its weight becasue if it did it would be about .345-.350 instead of about .250

That would be the difference at 300 yards between a wind drift 14.0" vs.  9.5" in a 10mph crosswind.

Sorry for this stupid question but what is OTM?  I presume BC is ballistic coefficient?

Open Tip Match and Ballistic Coefficient.

I think that with higher velocity bullets like the 5.56/223, it is not so much a matter of expansion vs fragmentation as it is a matter of "how do you want it to frag?"  True, FMJs and OTMs will frag, after yawing, but light HPs and BTs and SPs will most likely frag as well.  I ain't all that up on the construction of projectiles for .223, but for larger rounds bullets, makers do all they can to try and hold the thing together (bonded cores, homogeneous construction, variations in jacket thickness, a-frame type construction, etc) and limit fragmentation so as to retain some ability to penetrate deeply.

I am still trying to figger it out though.  

BCs

Nosler 55 BT    .267
Horn 60 V-Max  .265
Horn 60 SP       .264
Nosler 60 Part   .228
Sierra 65 SBT-GK  .303 (@ 2700+ fps) down to .287 (1100 fps or so)
Swift Scirocco 75 BT  .419

Quite a span and a range of bullets from medium weight varmint up through controlled expansion designs.  There's plenty to choose from depending upon your needs.  But regardless, the Sierra and definitely the Scirocco would hold their own against OTMs and perfrom much better than 55/62 grain ball.