223 ballistics & effectiveness - pt1 of 2

223 / 5.56 terminal and barrier performance

The following has been added from a post by Doctor Gary Roberts:

Only after proper foundational and ongoing repetitive refresher training, cultivating warrior mind-set, and ensuring weapon system reliability do you need to worry about ammunition selection. Most folks would be far better off practicing with what they have, rather than worrying about what is "best". As long as you know your what your weapon and ammo can realistically accomplish, it is all just a matter of training and shot placement. If you need to delve into the arcane subject of agency ammunition selection, below are the state of the art choices in .223/5.56 mm:

For general purpose combat use with 1/7 twist barrels from 0 to 600 yards, I would choose one of the combat proven 5.56 mm (ie. 5.56 mm NATO pressure loads, not .223 SAAMI pressure loads which run about 200 f/s slower) heavy match OTM loadings: either the Hornady 75 gr TAP (#8126N) using the OTM bullet w/cannelure or the equally good 77 gr Nosler OTM w/cannelure loaded by Black Hills, followed by the 77 gr Sierra Match King OTM-which, while exceedingly accurate, offers slightly reduced terminal effects. If your expected engagement scenario is at more typical LE distances, say out to 200 yards, then the .223 SAAMI pressure loads are fine. The experimental BH loaded 100 gr OTM exhibits impressive fragmentation, even at relatively low velocities, however, their trajectory is like a rainbow-definitely for use under 150 - 200 yards.

NOTE: For general purpose use, if stuck with 1/9 twist barrels, the heavy 70+ gr match OTM loads are not universally accurate in all rifles and the 69 gr SMK OTM, the 68 gr Hornady OTM, the Winchester 64 gr JSP (RA223R2), or one of the new Federal 64 gr TRU (223L) JSP, Hornady 60 gr JSP, or Nosler 60 gr Partition JSP's are the best choices to most likely run accurately in the majority of 1/9 twist rifles. You are screwed with 1/12 twists, I would probably choose the 55 gr Federal bonded JSP load (Tactical--LE223T1 or identical Premium Rifle--P223T2) in order to ensure adequate penetration.

If routinely engaging vehicles, the only LE .223 loads which effectively penetrate automobiles are the 62 gr Federal bonded JSP Tactical (LE223T3) and the similarly performing 55 gr Federal bonded JSP load. While not bad choices, neither the new Hornady 60 gr “barrier penetration” JSP nor the 60 gr Nosler Partition JSP bullets were quite as effective as the proven Trophy Bonded Bear Claws against glass in our testing. None of the OTM bullets, even the heavy 75 - 100 gr loads, offer good performance through automobile glass. FWIW, contrary to what many believe, 62 gr M855 FMJ also is not very good against glass.

If a short barreled 5.56 mm weapon, such as the Colt Commando, LMT/Crane Mk18 CQBR, HK416, HK 53, HK G36C, etc… is used with a 1/7 twist barrel, the 75 gr Hornady OTM, 77 gr Nosler OTM, 77 gr SMK OTM, and 100 gr BH OTM loadings offer acceptable performance; with a 1/9 twist, stick with the Fed 55 or 62 gr Tac bonded JSP's. Remember, with barrels under 14.5”, the effective engagement distance is significantly reduced compared to the longer barreled carbines.

Whatever projectile is used, it is best with a cannelure to prevent bullet set-back in semi-auto/auto weapons. Also, be cautious with the exposed lead on the JSP designs. Often they will run great for up to 200-300 rounds, but then mysterious feeding failures will begin as a result of lead build-up on the feed ramps. I have personally seen this occur with a variety of JSP's including 55 gr, 60 gr, and 64 gr in a recent LE training course. As soon as FMJ or OTM was substituted, all the feeding failures ceased.

Be sure to watch your ammo storage conditions. Temperatures above 150 deg F will degrade the powder and cause pressure spikes. Hint: Think locked metal conex containers in the mid-east, car trunks in the southern U.S., and storage areas near heaters in the northern U.S.

2) As evaluated by Troy

ALL CREDIT FOR THIS ARTICLE BELONGS TO TROY. I'm merely putting it in the content archive since he's been very busy.

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 consistency in construction required for match accuracy also results in consistent 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) (Edit 8/13/2008 - Some availble from at least one source - Nosler custom competition)

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.


Loads To Avoid

Anything loaded with a varmint bullet; all varmint bullets in this caliber will under penetrate 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 specialty 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.

(Rebuttals and other misc comments – mostly on forums)

Although the military is restricted to particular types of ammo, which is the strangest thing considering all the other types of ordnance and weapons used in war, we are not and apparently neither are agencies such as the DEA and FBI and they have chosen SP rounds for a host of reasons. Bottom line in this regard is that they work and work very well.

I have seen what a 60gr. Partition and a 62 gr. Tactical bonded round do to deer (90-170 lb. +/-) with 16 and 20" barrels at distances from 30-200 yards. I know deer are not humans, but then I have seen these rounds (DEA testing) penetrate gelatin and other mediums up to 100yards with complete efficiency...they do exactly what they are designed to do...penetrate all mediums, expand, cause severe upset/trauma (up to .50 cal) and so forth. FMJ or OTM rounds of whatever type cannot be said to be this effective and consistent through all mediums at these distances.

So I agree, with the DPX, Tactical Bonded, Fusion, Partition and maybe a few others, I do not have to worry about fragmentation or yaw at least up to 150 yards or better. In my thinking for SD certainly and SHTF, I will probably never take a shot past this distance.

And I’m sure no matter what kind of round is used, they all eventually at some distance neither expand or fragment.

I use 55 grain V-max for wild pigs here in West Texas. It drops them like a hammer

The superiority of heavier match grade 5.56 mm open tip match bullets compared to M855 has been conclusively demonstrated in recent combat use. The Mk262, MOD 0 using 77 gr Sierra Match King OTM bullet as loaded for NSWC Crane by Black Hills Ammunition (AA 53/NSN 1305-01-497-9996) was originally acquired for use in the 18” barrel Mk12 SPR; it has demonstrated better combat performance than M855 in the Mk12, M4, and M16A2 during the past few months, although some bullet set-back problems have been reported due to the lack of a cannelure. A cannelure enhances reliable weapon functioning and should be a mandatory feature of any U.S. military standard issue combat rifle and carbine ammunition--anyone who ignorantly argues otherwise needs to talk with skilled ammunition engineers like: Dave Emary at Hornady, Jeff Hoffman at Black Hills, Alan Corzine at Federal, and Dave Schluckebier at Remington.

The improved Mk262 Mod 1 loading uses a 77 gr Nosler OTM bullet with a cannelure, also loaded by Black Hills Ammunition, and has demonstrated better terminal performance compared to the 77 gr SMK bullet without a cannelure, as it has earlier yaw and somewhat deeper penetration, along with the improved combat reliability achieved with the cannelure. These results were confirmed by comprehensive joint FBI/USMC testing at Quantico in the Fall of 2002. While the Mk262 was initially procured for USSOC use, the Mk262, Mod 1 has been purchased by the USMC to replace M855 for use in Marine M4/M4A1’s. The 77 gr loading may eventually come to be in wider use by conventional, non-SOF units.

Compared to M855, the Mk262 variants offer improved accuracy, greater effective range, and more consistent performance at all distances. When used with an accurate weapon with good optics, such as the NSWC Crane/USAMU developed 5.56 mm Mk12 SPR, heavy match bullets allow precision engagement of individual targets beyond 600 meters, an impossibility with M855, since it is not capable of this level of accuracy. As an additional benefit, unlike M855, Mk262 is also effective when fired out of short barrel carbines, such as the 10” barrel length CQBR. Since M855 does not use flash suppressed propellant like the Mk262, the OTM loads offer an additional advantage over M855, as they have much less muzzle flash and are less likely to reveal the shooting positions of friendly forces at night or degrade night adapted vision. Although the Mk262’s are of an open tip match construction, they do not deform like a hunting bullet. Rather, they begin to yaw and then fragment by exactly the same mechanism and in the same manner as M855 and other FMJ ammunition.

(from DocGKR)

The U.S. M855/Belgian SS109 62gr FMJ boat-tail bullet has a partial steel core surrounded by a copper jacket and a muzzle velocity from a 20" barrel of 3034 f/s. When fired from the 14.5" barrel M-4 carbine it has a muzzle velocity of approximately 2800 to 2900 f/s and when exiting the muzzle of the 10" barrel XM-177/Colt Commando and 8.3" barrel HK53, velocity is generally reduced to below 2500 f/s. Wound severity with this cartridge varies depending on bullet fragmentation. The degree of bullet fragmentation is related to impact velocity. At lower muzzle velocities and as the range to the target increases, the bullet striking velocity is reduced, limiting bullet fragmentation, and decreasing wound severity. Down to a velocity of approximately 2700 f/s, generally around 150 meters from a 20" barrel and 75 to 100 meters from a 14.5 or 16 inch barrel, the bullet enters the tissue, leaving a small punctate entrance wound, and then travels point forward for approximately 4.7". If the bullet leaves tissue at this point, it will leave a small punctate exit wound and will have caused minimal tissue disruption along the wound tract. If it continues to travel in tissue, it will yaw to 90 degrees at this point, flatten, and fracture at the cannelure (the knurled circumferential groove around the middle of the bullet into which the cartridge neck is crimped). The flattened bullet nose remains in one piece and retains 60% of the original bullet weight. The 40% of the bullet behind the cannelure shatters into many fragments that can spread up to 2.75" radially away from the wound tract. These fragment each cut their own path through the surrounding tissue, multiply perforating it. Temporary cavitation then exerts its stretch effects on this weakened tissue, synergistically increasing the permanent cavity by detaching tissue pieces. Wounds in body segments thicker than 4.7" show greatly enlarged permanent and temporary cavities and can create stellate exit wounds of 3.5 to 4.7" measured form the ends opposite the skin splits. At a velocity below 2700 f/s down to 2500 f/s, generally around 150 to 200 meters from a 20" barrel and 100 to 150 meters from a 14.5 or 16 inch barrel, the bullet yaws, breaks at the cannelure into two large pieces, but does not fragment, reducing the wound severity. Below 2500 f/s, generally beyond 200 meters from a 20" barrel, 150 meters from a 14.5 or 16 inch barrel, and at the muzzle of shorter barrels, the bullet remains generally intact and does not fracture or fragment, but does yaw and may exhibit some flattening of the base. This lack of fragmentation significantly decreases wound severity. Depending how early yaw begins, wounds may be similar to those produced by the 5.45 x 39 mm Russian M74 53 gr FMJ bullet. If the bullet passes through tissue before yawing, small punctate entrance and exit wounds with little intervening tissue disruption will result. If the bullet yaws while traveling through tissue, the permanent cavity will be enlarged and disruption of those inelastic tissues susceptible to the stretch of temporary cavitation will be greatly enhanced. A small punctate entrance wound will be present and the exit wound may be punctate, oblong, or stellate depending on the bullet yaw angle on exit. M855 can produce insignificant wounds, similar to those produced by .22 long rifle if the bullets do not fragment or yaw. This can be caused by velocities below approximately 2500 f/s as when fired from short barrel weapons, when the range increases beyond 150 yards, or if the bullets pass through only minimal tissue, such as a limb or the chest of a thin, malnourished individual--when this occurs, the bullet exits the body before it has a chance to yaw and fragment at the cannelure. Performance of the older 55 gr M193 FMJ is nearly identical to the M855 discussed above.

In testing, the 55 gr M193 style FMJ exhibits minimal fragmentation and deformation after first passing through an interior wall. Strangely, the Winchester 62 gr M855 FMJ (RA556M855) “green tip” had exactly the opposite performance when first hitting an interior wall; it exhibits significant early fragmentation, with only the steel core tip penetrating beyond 19 cm. The lack of fragmentation by the 55 gr M193 FMJ when penetrating interior walls make it a poor choice when decreased penetration is desired during entry or urban operations. Both M193 and M855 offer poor performance after penetrating automobile windows, as they tend to disintegrate into small fragments which give insufficient penetration.

Acceptable performing 5.56 mm/.223 ammunition choices for law enforcement duty in 1 in 9" or faster twist barrels are noted below:

Black Hills 60 gr JSP
Winchester M-855 62 gr FMJ (RA556M855)
Federal 62 gr Tac JSP (LE223T3)
Winchester 64 gr JSP (Q3246)
Black Hills 68 gr JHP
Federal 69 gr JHP (223GM)
Winchester 69 gr JHP (S223M)
Black Hills 73 gr JHP
Black Hills 75 gr JHP
Hornady 75 gr TAP (80265)

The ONLY .223 load we shot which offered adequate penetration after shooting through automobile windshields was the Federal 62 gr Tactical (LE223T3). The trade off is that the Federal Tactical does not fragment, maintains the deepest penetration of any .223 bullet after penetrating walls, and as a result, may not be the best choice for entry or urban settings. (The older Federal 55 gr Tactical (LE223T1) for 1/12 twist weapons offers the same type of deep penetration and performance against automobile windows) The other .223 loads listed above which offer good performance for entry or other anti-personnel applications had insufficient penetration and retained mass after shooting through the car windows.

Unlike their .308 bretheren, the polymer tip .223 loads such as the Hornady 60 gr TAP (83286) and Winchester 50 gr Ballistic Silvertip (SBST223) have inadequate penetration in soft tissue and truly dismal performance when faced with penetrating glass.

The Federal 62 gr JSP Tactical (LE223T3) and Hornady 75 gr TAP are the only .223 bullets which we have tested which exhibit adequate terminal performance when fired out of barrel lengths shorter than 14.5 inches, however, effective engagement distance is limited compared to longer barrels.

5.56 mm/.223 weapons with a 1 in 12" twist rate are generally limited to bullet weights of 55 grains or less. At this time, only two ammunition choices are available which offer adequate penetration: M-193 55 gr FMJ and Federal 55 gr Tactical JSP (LE223T1), neither of which is ideal for CQB or entry use, as they fail to fragment when after penetrating interior walls.

Bullets of the SS109 type are manufactured by numerous countries. Although all SS109 types must be 62 gr FMJ’s constructed with a steel penetrator in the nose, the composition, thickness, and relative weights of the jackets, penetrators, and cores are quite variable, as are the types and position of the cannelures. As a result of the significant differences in construction between bullets within the SS109 category, terminal performance is quite variable--with differences noted in yaw, fragmentation, and penetration depths. Luke Haag’s papers in the AFTE Journal (33(1):11-28, Winter 2001) describe this problem.

It is difficult to generalize SS109 terminal performance--it would be more accurate to discuss M855, C77, L2A2, or specify the manufacturer or country of origin of the SS109 bullet in question.

With M855, fired by an M16A2 with a muzzle velocity at around 3025 f/s, penetration in bare gelatin is typically 12 to14” with significant bullet fragmentation. This holds up to a range of approximately 100-150 yards, where the velocity is around 2700 f/s or so, at which point the bullets no longer consistently fragment. At 150 to 200 yards, with a striking velocity of around 2500-2600 f/s, the bullets may break at the cannelure, but do not exhibit the significant fragmentation effects noted at closer ranges/higher striking velocities; penetration ranges from 13 to 18 inches. At 250 yards and beyond, the bullets do not fragment and exhibit progressively less base flattening as the range increases and velocity decreases below around 2200f/s; penetration is around 18-21”. See Fackler’s article in the IWBA Wound Ballistic Review 4(3):27-29, Spring 2000 for a nice description of the effects of range on the terminal performance of M855.

We did not test the Federal 62 gr JSP Tactical or Hornady 75 gr JHP TAP out of the 8.5” barrel HK53, only the 10.5” barrel Colt Commando, so I can not answer your question with complete accuracy. The Federal Tactical will likely not fragment if fired through interior walls with an HK53 and will probably penetrate more deeply than the Hornady TAP, but I can not verify this with specific tests using the HK53. I suspect that the TAP will be your best choice for entry, but I cannot prove it for your specific weapon.

What do you mean by “over penetrate”? In most cases, under penetration is a more significant problem than over penetration. With shots to the center of mass, if the bullet fails to have enough penetration to reach the large blood bearing vessels and organs in the torso, rapid physiological incapacitation is unlikely and your opponent may remain a lethal threat to you or the person(s) you are defending. Conversely, if your bullet completely penetrates the criminal who is attacking you and exits downrange, your bullet will certainly have had enough penetration to reach the large blood bearing vessels or organs in the torso. As a result, it is more likely to have caused sufficient hemorrhage to induce hypovolemic shock--the only reliable method of physiological incapacitation in the absence of CNS trauma. I suspect that law enforcement officers should worry more about the 85% or more of shots fired which completely MISS the intended target and immediately result in a significant threat to any person down range, rather than excessively worry about the relatively rare instance where one of the 15% of shots fired which actually hits the intended target, then exits in a fashion which still poses a hazard.

I am sorry that you must use the HK-53, as it has significant limitations. The short 8.5" barrel length of the HK-53 reduces the muzzle velocity of .223 bullets to the point where most loads do not fragment when fired out of this weapon. All you get is .22 LR performance. Would you stake your life on a .22LR ? In most cases, your duty handgun will cause more damage than an HK-53. Even with the best ammunition, you have a carbine which is marginally effective to at most 50 yards. In addition, the HK53 muzzle blast is severe—I imagine shooting an HK53 indoors on an entry is very uncomfortable—I hope you use hearing protection! Why not use the HK33? The overall length is not that different, yet the terminal performance with the 15.3” barrel is drastically improved--you have a carbine that is useful to 100-150 yards. Pat Rogers had an excellent article in the December 2001 SWAT magazine addressing LOP and stance--one point he makes is to shorten the M4 stock--close it all the way or only open it to the first position. This works very well and is what I do when carrying an M4. You could use the HK33 collapsible stock and shorten it down with your body armor and have the benefits of a compact weapon, but much better terminal wounding capability.

If a projectile is test fired using a downloaded powder charge to mimic the terminal effects of a longer distance shot, a different barrel twist must be used in order to maintain the correct rotational velocity, otherwise, errors will be introduced into the experiment.

Here are the fragmentation ranges for various barrel lengths for XM193:

20" - 190m
16" - 140m
14.5" - 95m
11.5" - 40m

Average muzzle velocity for XM193 is about 3050fps out of a 14.5" barrel. So it's probably good to about 75-100yds for reliable fragmentation. Personally I would use 68gr HP Hornady or 69gr HP Sierra for 'carry' ammo in an under than 16" barrel with 1x9 twist (if you can get the FBIs rifle ammo even better, IIRC their load is the Federal 64gr. For less than 16" 1x7 twist barrels my 'carry' ammo is 75gr Hornady TAP or 77gr Black Hills red box.

A FBI friend of mine out of Quantico says that their load works better than the 75gr and 77gr rounds. He says the 75gr and 77gr outperforms their 64gr loads in his words only in the 'naked man theory' meaning no barriers. I'm sure his opinion is a little biased as he did a lot of testing it and had something to do with its adoption.

I think it’s interesting that there are differing opinions on this round. In a class with Jim Smith, of Spartan Tactical, he mentioned he liked the M855.

In Kyle LAmbs book, he also mentions he thinks it’s a good round.

Paul Howe, mentioned his dislike of it in BlackHawk Down, but never mentioned it in the few classes I've taken with him.

I wonder why the differing opinions of guys with similar backgrounds?

I have used the M855 to good result, and would definitely take it over a varmint round. If you hit 'em where it counts, caliber and construction don't matter as much. But better performing rounds make those hits easier and give a greater degree of error in shot placement.

Pros of M855-
Deep penetration
Low failure to fire rate

Late yaw
Inconsistent wound pattern
High velocity required for fragmentation
Sub-par accuracy

Add to these the price demanded for LC M855. I would prefer Mk262 Mod 1 far above M855 for real use, and when I have to pay for each shot I train with XM193 (for close stuff).

The new fat kids on the block, such as the MK262 and 5.56 TAP greatly reduce or eliminate the Cons of M855 (and 5.56 in general) except for fleet yaw variation and barrier penetration.

From the internet it would seem that M855 is barely acceptable to be used against rabid prarie-dogs or it is a heat-seeking circular saw.

I am firmly in the shot placement over caliber/construction camp, but I am happy to embrace improvements to my effectiveness.

(ETA- A certain group noticed that their complaints about M855 immediately dropped when they equipped their weapons with magnified optics. Hmmm.)

I'm a fan of the M193 loads personally, being a velocity freak and all.

The other thing, the M193 load is said (and I would believe it) to be marginally superior to the M855 load when it comes to defeating harder materials, materials lighter than hard armor at least. The additional velocity of the M193 load helps it overcome the fact that it is composed of an all lead core, seems that the steel penetrator in the M855 load really only comes into play at longer distances where the heavier 62grn bullet is holding out a velocity/retained energy advantage to the 55grn bullet.

A bit of shooting against various steels seems to show a slight edge to the M193 at closer distances.