1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

What the M855 really does

Discussion in 'Rifle Country' started by horatius, Mar 17, 2006.

  1. horatius

    horatius Member

    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.
  2. YellowLab

    YellowLab member

    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.
  3. Stiletto Null

    Stiletto Null Well-Known Member


    For that matter, pretty much any of what you posted is at Ammo Oracle.
  4. lamazza

    lamazza Well-Known Member

    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.
  5. Stiletto Null

    Stiletto Null Well-Known Member

    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.
  6. horatius

    horatius Member

    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.
  7. Hawkmoon

    Hawkmoon Well-Known Member

    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.
  8. Husker1911

    Husker1911 Well-Known Member

    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!
  9. horatius

    horatius Member

    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.
  10. horatius

    horatius Member

    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.
  11. Correia

    Correia Moderator Emeritus

    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.
  12. Sylvan-Forge

    Sylvan-Forge Well-Known Member

    :neener: Excuse me while I whip dis' out


  13. Jubei

    Jubei Well-Known Member

    Okay...you win.:D

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

  14. Woodsmoke

    Woodsmoke Well-Known Member

    Newbie Question

    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?
  15. Stiletto Null

    Stiletto Null Well-Known Member

    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).
  16. One of Many

    One of Many Well-Known Member

    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.
  17. Bartholomew Roberts

    Bartholomew Roberts Moderator Emeritus

    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.

    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.
  18. Husker1911

    Husker1911 Well-Known Member

    Careful, One of Many. Don't claim to own someone. Get back on subject............
  19. horatius

    horatius Member

    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.
  20. Hawkmoon

    Hawkmoon Well-Known Member

    Isn't that what mil-surp Mausers are for? :evil:

Share This Page