What the M855 really does


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horatius
March 17, 2006, 11:32 AM
Gentleman, there are some misconceptions about terminal ballistics and wounding effects. First, Dr. Martin Fackler’s research at the international wound ballistics assn. shows that the terminal effects of an M193 and a M855 round are exactly the same. Second, the wounding mechanism of lightweight, high velocity rounds such as the SS109 / M855 is from fragmenting, not tumbling. Any bullet with a pointed nose will tumble when it changes medium because its center of gravity is to the rear. A 7.62mm bullet, regardless of its case length, creates a greater permanent wound cavity than its diameter through tumbling. Fragmentation occurs when a bullet is going very fast, changes medium and explodes. This is what happens to a 5.56mm round when it is going faster than 2700 fps. For a 20” barrel, this is inside 100m. Between 100m and 200m or 2700 – 2500 fps, the bullet splits in half. The notion that, “the bullet is going so fast that it punches right through,” is completely wrong. Bullets penetrate well when they are going slow enough to maintain their shape. That is why maximum penetration for an M855 round is at 200m. This is where the bullet no longer breaks up but has a relatively high velocity and thus energy. Look up the penetration tables in the M16A2 FMFM and you will see.
The next misconception is that 5.56mm is ineffective. According to Fackler, the 5.56mm bullet does considerably more damage than a 7.62mm bullet within its design envelope. People rant about 7.62 being so effective but the only people who shoot it are snipers and machine gunners. The later employ multiple hits while the former have excellent shot placement. The soviets switched from the 7.62 x 39mm round to the 5.45mm round 30 YEARS AGO. What else needs to be said about the effectiveness of fragmenting bullets at short-range? Also, one can carry twice as much ammo.
The last bit is what happens to someone when he is shot. To kill someone means to destroy his central nervous system. Period. It is only when this happens that someone is physiologically incapacitated, i.e. it is not possible for him to do anything. The two ways to accomplish this are by destroying the CNS with bullets or through blood loss. When we shoot someone anywhere but through the brain stem and or cerebellum, we are just causing his body to lose enough blood so that his brain will die. According to Dr. Ken Neward, if you shoot someone through the heart, the fastest he will bleed to death is 4.5 seconds. This does not take into account that when one is full of adrenaline, the body is doing everything it can to prevent death through blood loss. Thus, when people get shot, they don’t always fall down. In fact, one can run pretty far in 4.5 seconds. For immediate incapacitation from blood producing hits, the mental state of the enemy is the single most important factor. Dr. Newgard wrote that for small arms, it is impossible to create a one shot stopper.
Another issue is how many times the subject was actually shot. We’ve all heard people say, “I shot that guy 5 times and he didn’t drop.” Well, did you count the bullet holes? No. Then you didn’t hit him 5 times. Maybe 3 times. And as we see from Newgard’s work – if he ran a bit and then fell, that makes sense. Point is he eventually died.
The 5.56mm is great, shot placement is everything and against dedicated opponents, they don’t drop after one shot. If the enemy is close enough that you need him to die inside 4.5 seconds, shoot him in the head.

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YellowLab
March 17, 2006, 12:14 PM
Is this some sort of carry over from AR-15.com?

I know you really like your black gun, but .30-06 has killed more people than 5.56 (been in two world wars).

Shot placement? Where did that adreneline go when the shooter is under stress? Yes, any bullet can kill anyone. People die from .22's all the time.

But a .308 or .30-06 will go THROUGH the wall, car, windshield and get the bad guy.

Stiletto Null
March 17, 2006, 12:22 PM
Cripes, man. LINE BREAKS ARE YOUR FRIEND.

For that matter, pretty much any of what you posted is at Ammo Oracle (http://www.ammo-oracle.com).

lamazza
March 17, 2006, 12:26 PM
Well I DO love the black gun :) and another plus to this, plenty deadly, 5.56 round is that you can carry twice as much of it.

Stiletto Null
March 17, 2006, 12:28 PM
True, that. Load up with M193 in a 20" barrel, and anyone inside 200yd is in very real trouble.

It'd be interesting if someone would make a lightweight 60gr ballistic tip round, specifically for short range defensive use.

horatius
March 17, 2006, 12:31 PM
1. A bullet that goes through walls, cars and can still someone is exactly what I don't want. Geometry of fire is crucial, especially in urban areas. Second, .308 and .30-06 make for very slow follow-up shots or multiple targets which are essential in CQC. So, again I come back to small, fragmenting bullets.

Hawkmoon
March 17, 2006, 12:39 PM
What Horatius failed to explain is that the fragmenting of the 5.56 round is not caused by impact (as with a Glaser safety round), but by the end-over-end tumbling upon impact. If the bullet is traveling fast enough, the rotational speed of the tumbling causes the jacket to fracture at the cannelure.

2700 fps is the minimum speed at which this can reliably be expected to take place. The problem with the M855/SS109 round is that out of a 16" barrel or the even shorter M4 barrel, the M855 round doesn't carry 2700 fps beyond 100 meters. The M193 55-grain round, by contrast, carries 2700 fps out to or a bit beyond 150 or 160 meters.

This is why many experts suggest M193 as a general purpose home defense round rather than M855. I have subscribed to that logic, although I can see some logic in keeping one or two magazines loaded with M855 for the contingency that you might need to penetrate an automobile at closer range. The M855 has a penetrator core, whereas the M193 does not.

Husker1911
March 17, 2006, 12:41 PM
Choose your modern uber-magical modern black rifle, I'll keep my FAL thank you. If we find ourselves on opposite sides when the crap starts, so long as I can back you off to 600-700 yards, I OWN you!

horatius
March 17, 2006, 12:42 PM
As far as anti personnel ammo goes, the 75gr Hornady TAP does is fantastic. It does a much better job than M193 at causing tissue damage and will kill someone after going through a windshield.

horatius
March 17, 2006, 12:47 PM
Husker, you're course of action involves much hope. In an urban area, it is impossible to see someone who is 600-700 yards away - let alone have good target ID. Second, at that range, I'm going to use machine guns to fix you and indirect fires to blow you up. So, I think I'll own you.

Correia
March 17, 2006, 01:03 PM
Mod note, I don't give a damn who owns who, okay? Get back to the subject.

Sound like a bunch of grade schoolers arguing about who's dad is tougher.

Sylvan-Forge
March 17, 2006, 01:11 PM
:neener: Excuse me while I whip dis' out





http://upload.wikimedia.org/wikipedia/en/4/4f/Nuclear_artillery_test.jpg

:neener:

Jubei
March 17, 2006, 01:21 PM
Excuse me while I whip dis' out

Okay...you win.:D

But you'd better be upwind or the fall-out's gonna make your victory a little sour.

Jubei

Woodsmoke
March 17, 2006, 01:28 PM
What about bullets like the V-Max? Would this be a suitable alternative for self-defense out of a 16" barrel or would you recommend something else? Inside 200 yards how does it compare to the M855?

Stiletto Null
March 17, 2006, 01:35 PM
That's a good question, I've never seen gel tests for the popular 45~50gr varmint rounds (which are designed to fragment like mad).

One of Many
March 17, 2006, 02:39 PM
Much ado is made of the light weight of the 5.56mm round, and how it allows carrying twice as much ammunition, and allows much quicker follow-up shots. If a .30 rifleman fires one aimed round for every three 5.56mm rifleman's rounds (maybe not well aimed) fired on one target, the .30 rifleman will still have ammo left when the 5.56mm rifleman has exhausted his supply.

Fire control and discipline makes for an effective warrior; spray and pray just wastes a lot of ammo. The tendency to just point the muzzle in the general direction, and empty the magazine at full auto (or multiple 3 round bursts), does not take as many enemies out of action as a rifleman that is careful to aim his semiauto rifle before pulling the trigger. That is not to say that every 5.56mm rifleman does not aim before shooting, but the .30 semiauto rifleman is more likely to be certain where his bullet went when he pulls the trigger. There is an appropriate time and place for high volume suppressive fire, just as there is for carefully timed and placed fire directed at individuals, (not directed at areas).

There are advantages and disadvantages for each weapon type; a time and place for each - no one weapon is the be-all and end-all for every possible circumstance that may develop.

Wars are won with a combination of weapons, brains, and information about friends and enemies. The person with brains chooses the right weapons for the tasks at hand, chooses the right time and place to employ the weapons, and takes advantage of the strengths of his friends, and the weaknesses of his enemies. The warrior with only one weapon for all circumstances will likely lose his war, even though he may win some battles.

Bartholomew Roberts
March 17, 2006, 03:48 PM
First, Dr. Martin Fackler’s research at the international wound ballistics assn. shows that the terminal effects of an M193 and a M855 round are exactly the same.

Actually they aren't. M855 has a more complex bullet construction than M855 in order to accomodate the steel penetrator. Since the specs for M855 are only related to accuracy and penetration, there is no consistent standard tested with regard to terminal performance. Differences in jacket thickness and bullet construction effect the terminal ballistics. You can have one lot of M855 that will fragment as low as 2300fps and another lot that won't fragment at all at 3,000fps.

M193 is more likely to fragment because without the penetrator requirement, it is simpler to make the bullets more consistently from batch to batch. It also has a higher initial velocity; but even M193 yaws too early or too late around 25% of the time according to Fackler.

If a .30 rifleman fires one aimed round for every three 5.56mm rifleman's rounds (maybe not well aimed) fired on one target, the .30 rifleman will still have ammo left when the 5.56mm rifleman has exhausted his supply.

You know, all I have ever done is force-on-force with Simunitions. So I don't claim to be particularly knowledgable here; but I noticed talented shooters (Grandmaster and Master) who advocated this same theory running out of ammo and having to do mag changes at distances of 7yds during Force-on-Force. I'll certainly agree that a .30 rifleman who can make a hit every time he fires a round will beat a 5.56mm rifleman who needs three rounds to get a hit. I'd just suggest that the number of people who think they are that one-shot rifleman is a lot higher than the number of people who are that rifleman. For the rest of us who aren't so talented, 5.56mm is a good deal.

Husker1911
March 17, 2006, 07:18 PM
Careful, One of Many. Don't claim to own someone. Get back on subject............

horatius
March 17, 2006, 07:23 PM
Why are 5.56 and 7.62 shooters separated into spray and pray shoorters and accurate marksmen? A rifleman is a rifleman is a rifleman. Given that one can do the business, at close range (inside 200m) 5.56 is the way to go because it creates more tissue damage from fragmenting, has higher capacity, and is much faster for multiple shots/targets. At distances inside 25m, 5.56mm rounds are far and away better than 7.62, For longer range, 7.62 is superior since it bucks the wind better and does more damage.
I think is important to have the right tool for the right job.

Hawkmoon
March 18, 2006, 12:08 AM
Choose your modern uber-magical modern black rifle, I'll keep my FAL thank you. If we find ourselves on opposite sides when the crap starts, so long as I can back you off to 600-700 yards, I OWN you!
Isn't that what mil-surp Mausers are for? :evil:

Lebben-B
March 18, 2006, 06:54 AM
It'd be interesting if someone would make a lightweight 60gr ballistic tip round, specifically for short range defensive use.

Hornady TAP For Personal Defense makes a 60 gr .223 w/a ballistic-type tip.

Mike

One of Many
March 18, 2006, 02:31 PM
Careful, One of Many. Don't claim to own someone. Get back on subject............

Huh ???

It has long been recognized that longer/heavier projectiles retain more energy at long ranges, and are more effective at killing the intended victim (whether hunting big game or human enemies). The tradeoff is the ballistic arc associated with such ammunition. The original 5.56mm ammo was lightweight, and used a slow twist barrel for stability. Then it was discovered (again) that a need existed for heavier bullets, and the corresponding barrels with a slower twist rate. The 'flat shooting' cartridges have always been the high speed, light weight bullet type, that are effective on a smaller range of targets.

You can easily kill a small animal as well as a large animal at long ranges, with the heavier and more powerful (retained energy) cartidges; It is more difficult to kill a large animal at long range with a smaller and less energetic round. Granted that when talking about military ammo, we are referring to the ability to kill and injure humans (and they die much easier than wild animals), the choice of ammo still is determined by the purpose it is intended to fill; short range, high volume firefight, or long range precision (sniping) engagement. You use the tactics and tools that are appropriate for the task at hand.

lamazza
March 19, 2006, 06:30 PM
...yes but, just about any modern day scenario is going to be urban...and 600 yards or even 500 or 400 yards is a pointless comparison unless you shooting at someone in a red wheel chair.

Hawkmoon
March 19, 2006, 08:19 PM
Is 100 to 200 yards reasonable in an urban scenario? Is a 16" barrel a reasonable possibility in the urban scenario? If so, the difference between the two rounds is still significant.

The following is from the AR15.com site:
Q. At what range will M193 fragment? How about M855?

Assuming true M193 or M855 ammo, velocity is the key. Velocity is dependent on barrel length and environmental conditions.

As barrel length increases, the bullet is propelled faster by the expanding gasses in the barrel, imparting more velocity on the bullet, resulting in a longer range before a fired bullet drops below 2700 fps. A shorter barrel imparts less velocity, and therefore the bullet has less range.

Temperature, altitude and humidity are other factors. As temperature or altitude increases, air becomes less dense and bullets travel faster. Contrary to common conceptions, as humidity increases air also becomes less dense and helps bullets retain velocity.

It is important, then, to keep in mind that any statistics given can only be approximate and can be affected by a wide range of factors. But as a baseline, these numbers are what you could expect for 75° F, 25% humidity, at sea level, from various barrel lengths:

Distance to 2700 fps . . 20" Barrel . . . . 16" Barrel . . . . 14.5" Barrel . . . . 11.5" Barrel
M193 . . . . . . . . . . . . 190-200m . . . . 140-150m . . . . .95-100m . . . . . 40-45m
M855 . . . . . . . . . . . . 140-150m . . . . . 90-95m . . . . . .45-50m . . . . . . 12-15m

As you can see, barrel length and ammo selection make a major impact on fragmentation range.

Chris Rhines
March 19, 2006, 09:14 PM
The terminal effect of a bullet that misses the intended target is the same whether it's a .223 or a .308 - nada.

Worry about getting the hits first.

- Chris

MTMilitiaman
March 20, 2006, 12:18 AM
Okay so if we first admit that immitation is the sincerest form of flattery, and that the 5.45 is an immitation of the 5.56, and that majority rules in this regard, then we must also compare the weapons systems and acknowledge that while very few people have attempted to copy the operating system of the M16, there are numerous such efforts to do so with the Kalashnikov. Therefore, the AK is the better weapon because it is immitated most often, right? If some of you object, then you must also admit that such assumptions are invalid when discussing cartridges.

Secondly, regarding 7.62x39 v 5.45x39, the 5.45 still relies on tumbling as its primary wounding mechanism. The bullet if fairly long, however, being sufficently heavy for caliber, and having a large air pocket in the nose, that when tumbling it tends to displace a fair amount of tissue. The Yugo M67 ball round for the 7.62x39 behaves in a much similar manner, also possessing an air pocket in the nose, and according to Fackler creates wound channels nearly identical to those of the 5.45mm, tyically yawing within ~9 cm of ballistic geletin--a full 17 cm sooner than the predecessor M43 ball round. Wolf FMJs are constructed like the Yugo round and when discected will show the air pocket comprising the forward 1/3 of the bullet's length. The only difference is that even if these rounds don't yaw, they are at least .311 caliber.

Thirdly, you are comparing bullets designed to tumble and fragment quickly in flesh with those designed with relatively little attention give to this. Try comparing bullets of equal design, and it again becomes absurd to claim the 5.56 is as effective as any 7.62mm. Put a 75 gr Vmax in the 5.56, 123 gr Vmax in a 7.62x39, and a 155 gr Vmax in a 7.62x51, and the effectiveness, given equal shot placement, will be in that order. Fackler provides such evidence by showing the effectiveness of West German 7.62x51 ball ammo, which had a different alloy in the jacket, making it more brittle. It tended to act in tissue much like the M193, but with wound channels fully twice the diameter of those experienced with the 5.56.

Finally, if you have a round that does twice the damage, then you don't really need twice the ammo. Wrapping everything up, the 5.56 may or may not fragment, but the 7.62mm isn't getting any smaller.

Cosmoline
March 20, 2006, 12:53 AM
The next misconception is that 5.56mm is ineffective. According to Fackler, the 5.56mm bullet does considerably more damage than a 7.62mm bullet within its design envelope. People rant about 7.62 being so effective but the only people who shoot it are snipers and machine gunners.

Only if you artificially limit yourself to FMJ bullets. The advantage of the 5.56 comes from its inherent failure to maintain its structure at high speeds. This is ONLY an advantage because of the Hague Convention. If you remove the artificial legal constraints, the 5.56 resumes its place as a gopher round. This is why the only people who fire the 7.62/.308 are NOT snipers and machine gunners. It's widely used as a hunting round, especially in semiautomatic rifles and short action bolt guns.

Don't Tread On Me
March 20, 2006, 02:14 AM
FAL having better stand-off range? Only if you can hit someone 700 yards away with it. Consider that an AR-15, with handloads and a FF tube can score headshots at 500 yards(not that you would go for them, but the accuracy is there), and that with 30 minutes of training an 10 year old girl can be trained to score COM hits at 400...I seriously doubt a FAL is necessarily a better "stand off" weapon just because it is .308. Both being scoped, the AR is easier to shoot and is more accurate with less hassle involved. Not to mention, you won't lose your sight picture with the AR, thus you can deliver a constant barrage of well-aimed, precision fire at any target.


If slow, well aimed shots won violent armed confrontations, then we'd all be better served with muzzle loaders. Sorry, but spray is superior to slow fire. With a 5.56 you can spray without having to pray, thanks to the low-recoil. The name of the game is the fastest, highest volume fire that you can direct accurately enough to get hits. "Good enough" counts. Don't need 10 rings, just hits.


If the 7.62x39 were such a great 1 shot manstopper, the AK-47 wouldn't have been select fire. No need for full auto when .30 cal lets you do the job with 1 well aimed shot. Also, full auto is a waste of bullets when you should be aiming in semi-auto mode instead. Dumb Soviets! They are wasting 1-shot stopping power by building a select fire rifle.


An AR-15 can be every bit the "marksmans" rifle as any .30 cal. If you can take the time to aim and guarantee 1st shot hits, then you can do that with an AR too. The question then becomes, is the 5.56 good enough with one hit? I think so. I dunno too many people who will just shake off a chest hit from a .223...likewise they won't fare well with a x39 or 545 or .308 going through them either. However..........


.........anything worth shooting is worth shooting twice - regardless of caliber. More holes = better. Caliber is secondary.

Onmilo
March 20, 2006, 09:03 AM
M855 62 grain penetrator ball cartridge.
I have never used this stuff to pop a human being, what I know about it comes from the target range where I have sent more than a few of these rounds down range.

What I can tell you is the stuff isn't all that accurate.
Even the new improved versions just don't group all that well, especially if the range exceeds 300 meters and I thought that was one of the big brew hoo hoos about this cartridge.
The ability to shoot out to 800 meters and retain enough energy to penetrate a steel helmet.
All well and good with the exception that most lots of this ammunition from a number of different global sources cannot group well enough to hit a helmet at that distance.

The US Army still teaches battlefield zero of 300 meters and it may be a good thing.
Heck, I am begining to agree with several sources that the M16 combat rifle really does not need that tricky full adjustment rear sight.
The M16/M16A1 semi fixed sight was rugged and more than adequate for the combat ranges the rifle is normally used to engage.

There are suppossed to be fixes to this problem and newer lots tend to group better but if groupability is so much better then why does the Military issue 77 grain Black Hills ammunition to select groups of Servicemen who are most likely to go in harms way??

Leave the long range stuff to the Ma Deuce and the artillery.

Stiletto Null
March 20, 2006, 11:19 AM
I think it's Nosler, actually.

It's for designated marksmen and such (well, I think Marines are trying to make it standard for everybody, but that's the MARINES :D), who get the fancypants rifles and higher-powered optics.

Jeff White
March 20, 2006, 03:41 PM
Secondly, regarding 7.62x39 v 5.45x39, the 5.45 still relies on tumbling as its primary wounding mechanism.

All spitzer bullets tumble. It's basic physics, when the weight of the projectile is in the back and it hits something, that weight is going to attempt to move forward and the bullet will tumble. The big difference in terminal effects is how far the bullet penetrates before it yaws completely around and ends up base first.

I think it's Nosler, actually.

Black Hills makes the MK262 and MK262 MOD 0.

Jeff

MTMilitiaman
March 20, 2006, 03:58 PM
Jeff, I know. The implication from the original poster was that the 5.45mm relied on fragmentation similar to the 5.56. My understanding is that this is incorrect, and the round is designed to accelerate tumbling in soft tissue by either causing the front of the projectile to flatten upon impact, or to allow inertia to move the core, and thus the center of gravity, forward upon impact. This does not rely on fragmentation and is as such less reliant on velocity, according to my understanding.

Don't Tread On Me
March 20, 2006, 05:43 PM
MTmillitiaman, I've wondered that very same thing. The 5.45 is built with a very solid and hard jacket (like the Wolf .223) and probably doesn't fragment.

It's been a while since I've read through all those Fackler docs, so it might all be there.

Here's the question, if the bullet is designed to tumble only, is there a speed threshold where this effect ceases to occur? Would sending it out at 3,330fps prevent tumbling? Or would sending out at 1,800fps prevent it? Or does it tumble regardless of velocity?


As for 5.56...here's the beauty of the new bullets. The new heavies for the .223 not only fragment, but they've pretty much added the whole early-yaw tumble effect of the 5.45. Best of both worlds. Have you seen the length difference between the Hornady 68gr HPBT and a standard 55gr FMJ? It is quite a huge difference! The Hornady 68 is like a long skinny spike, while the 55 looks more like a normal bullet. The 68 is very 5.45'ish in a way. If it doesn't fragment, it will certainly yaw because it is as butt heavy as you can get in that design.


The heavier .223 bullets are longer. Being that diameter is constant and unchanging, adding weight forces them to be longer. Most of that weight remains in the center to rear of the bullet and becomes part of the boattail. It cannot be added to the front a whole lot because the .223 cartridge must still fit into a USGI magazine. The 75 hornady is about the same length as the 68. The extra 7gr is added to the boattail area and the profile of the nose isn't as sharp on the 75.

The lighter .223 bullets go into a case pretty much at or a hair deeper than the neck. The heavies go past the neck all the way to the bottom of the shoulder of the case often pushing into the powder. Some powders and 77's create compressed charges. The nose of these bullets are left hollow and they now have 5.45 properties.


If I had to guess, if these bullets were built with strong jackets, they would tumble just like the 5.45 (maybe worse). Don't confuse the fact that they tumble very quickly in tissue then explode because of lateral forces on the bullet (fragmentation). That doesn't mean the only wounding factor involved is simple fragmentation. If they didnt' fragment, they'd probably tumble like the 5.45.


The 77's and 75's begin to yaw just a few CM's upon entering tissue. Quite impressive compared to the 5.45. More weight, quick tumble, large fragmentation. These are about as good as it gets terminal performance-wise for the small-bore world.

Bartholomew Roberts
March 21, 2006, 08:32 AM
Here's the question, if the bullet is designed to tumble only, is there a speed threshold where this effect ceases to occur? Would sending it out at 3,330fps prevent tumbling? Or would sending out at 1,800fps prevent it? Or does it tumble regardless of velocity?

My understanding (and I always welcome input from those who have a better foundation in the subject) is that all non-expanding bullets tumble at all velocities but that as bullet shape and velocity change, WHERE it tumbles may be an important difference. It may tumble so late that for practical purposes it won't tumble inside most deer-sized objects. I do know that 9mm FMJ will tumble and have seen X-rays of the phenomenon inside gunshot victims.

As I understand it, tumbling is a basically a stabilization issue. In order to put a fast enough twist on a bullet for it to stay stable inside a mostly water medium like tissue, the bore would need a twist that would make it look like it was threaded. Since it doesn't have this stabilization, any non-expanding bullet that has more weight behind the nose than in front of it yaws due to center of gravity. Expanding bullets don't usually yaw because the center of gravity moves as the bullet expands.

atblis
March 21, 2006, 09:25 AM
Fragmenting 7.62 > Fragmenting 5.56

Don't Tread On Me
March 21, 2006, 01:05 PM
Right, I understand that part. Everything tumbles in a tissue medium, but for the sake of the discussion, it's safe to regard very late tumbling as no tumbling at all. Any round that begins to tumble at or after the point of exit isn't effective as to what we're discussing. What I was wondering is if there is a performance-based velocity threshold on the 5.45.

Let's say you dermine that a 545 or 75gr .223 needs to tumble within a certain amount of inches after impact. Say, you want it to be 90 degrees turned no later than 4" upon entry (just an example)...does velocity effect how quickly this will happen? Is there a threshold at the top or bottom of the velocity spectrum where this effect changes and thus negatively effects performance of the yaw? Will it not yaw at all under 2,300fps? By not yawing, I mean, in the way it was meant to yaw to produce massive tissue damage (all bullets yaw regardless of speed)

I'm assuming that neither the 545 or 75gr .223 can fragment, they are each hollow nosed, and have solid-non fragmenting jackets.


MTmilitiaman's idea is that the 5.45 has an advantage over the .223 in that it doesn't need the > 2,700fps factor for fragmentation. If you get nailed by a 5.45 at 500 yards and its only doing 1,800fps or something, that the simple design of the long bullet with airpocket nose will still create a significant yaw effect. I'm wondering if that is the case or not.

Bartholomew Roberts
March 21, 2006, 02:10 PM
MTmilitiaman's idea is that the 5.45 has an advantage over the .223 in that it doesn't need the > 2,700fps factor for fragmentation. If you get nailed by a 5.45 at 500 yards and its only doing 1,800fps or something, that the simple design of the long bullet with airpocket nose will still create a significant yaw effect. I'm wondering if that is the case or not.

My thinking would be that 5.56x45 still yaws even at 1,800fps since it is still tail heavy and more rounded, much slower rounds like 9mm will yaw inside a human body. I also imagine it would make a bigger hole in yawing since it is both wider and longer than 5.45x39, though I am pretty skeptical the small difference would amount to any practical benefit.

MTMilitiaman
March 21, 2006, 02:22 PM
Hmm. I guess I really don't care. I'll stick to 7.62x39 and let everyone else get all giggly about the .22 centerfires.

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