GUN Here's my paper on the M855 vs. the M80

Discussion in 'On Topic' started by footratfunkface, Apr 28, 2003.

  1. footratfunkface

    footratfunkface New Member

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    okay, i've got a few hours before i leave for school to turn this thing in. i figure i'll let you guys try to shoot it down, and if it stands up to that, it's a tight argument. i also challenge you to find grammatical errors. i don't think i've got any, but i might've missed one.


    The Firefight Between 7.62mm NATO and 5.56mm NATO

    Throughout the history of warfare mankind has always sought the most effective weapons to use in combat against his adversaries. In the beginning, those weapons were sticks, stones, spears, arrows, and other simple weapons. As technology advanced, gunpowder was discovered, and not long afterward, it was used as a propellant for projectiles. At first, only cannons were effective. Some time later, the size of the guns was reduced, and these “hand cannons” became the world’s first small arms.

    For centuries, the development of firearms was geared toward firing rounds as fast and accurately as possible. Reloading in the days of black powder rifles took a huge amount of time, during which a man’s enemy could advance on him a great deal and fire shots of his own. Thus, the rifle cartridge was invented. During the last century, however, the development of small arms for the military has been geared toward making a rifle that is best suited for the infantry rifleman and is capable of reliable, accurate, deadly fire against unarmored enemy personnel.

    Such rifles have existed and been used very effectively by the military for decades. The most current research in small arms is not on the weapons, but rather, on the rounds that those weapons fire. The goal is to have a round that is easily carried, effectively incapacitates a soldier’s enemy, and is accurate at normal infantry combat ranges. Two such rounds have been used by the United States military in the past 30 years. These rounds are the M855 round and the M80 round. Some would argue that the M80 round is a better choice for infantry weapons because it is larger and more powerful. However, those inherent characteristics are precisely what make the M80 less suited to infantry combat. The M855 round is lighter, has better wound ballistics, and has better recoil properties than the M80.

    Bullet weights are measured in grains. For comparison, there are 7,000 grains to one pound. The M855 round has a sixty-two-grain bullet measuring 5.56 millimeters in diameter. The round, from the bullet-tip to the end of the casing, is forty-five millimeters long. The M80 contains a 150-grain bullet and is 7.62 millimeters in diameter. It is fifty-one millimeters long. Quite evident is the size difference between the two rounds, as is the weight difference. The M855 is much lighter and smaller than the M80.

    Possibly the most important property of a bullet is its ability to incapacitate a soldier’s enemy quickly. The only way to kill a man with one shot is to hit the base of the brain, where all involuntary functions are controlled. Such an area is nearly impossible to hit in combat, so the next best thing is incapacitation of the threat. Whether or not the adversary dies is irrelevant, because death is often a side effect of incapacitation. In order to incapacitate the enemy to an extent where he is no able to attack, the enemy must sustain such massive trauma to his vital organs so as to render him unconscious or physically incapable of functioning. The only way to guarantee hitting a major organ is to use a bullet that creates as big a hole as possible in the enemy’s body.

    The hole a bullet creates in a body as it passes through really consists of two main parts. The first is the temporary cavity. The temporary cavity is the temporary hole that the bullet creates as it goes through flesh. The shock wave created by the supersonic bullet is the primary way that this temporary cavity is created. The bullet may also, by a suction-like effect, pull bodily tissues in the direction of its travel, then let them snap back into place after its passing. This is called cavitation.

    The other main part of a bullet’s wound tract is the permanent cavity. While the temporary cavity may expand to large sizes and return to its original space with no serious damage to tissues, the permanent cavity is flesh that is permanently displaced. This cavity is smaller than the temporary cavity but much more damaging. Bodily tissues are completely removed from this area.

    There are two different ways that the M80 and M855 rounds create their wound cavities. The M80 creates its permanent cavity through the yawing and tumbling of the bullet. According to Dr. Martin Fackler, an Army surgeon and expert in gunshot wounds, the M80 round relies only on yawing, which is a rotation in the lateral direction, to create its permanent wound cavity. As the bullet enters the body, bodily tissues, which are much denser than air, destabilize the bullet. The bullet’s weight, due to its shape, is mostly in the rear, so the bullet starts to yaw as the rear swings around toward the front. As the bullet yaws, tissues are destroyed. The more perpendicular the bullet is to the line of travel, the larger the permanent cavity is. The bullet becomes stable again as the base of the bullet comes into the forward position, and it will exit the body in this orientation (Fackler).

    [​IMG]

    The M855 round, while smaller, creates much larger temporary and permanent wound cavities than the M80. The M855 does its damage by way of fragmentation of the bullet. Fragmentation occurs in the M855 round because the bullet begins to yaw for the same reasons as the M80, but as it reaches a point almost ninety degrees from the direction of travel, it breaks into one large piece and many small pieces. These fragments each serve to cut or crush tissue and make a much larger permanent cavity than yawing alone could do.

    [​IMG]

    In addition to terminal wound ballistics, there is another category of performance to consider: penetration. As one website states, the M80 will penetrate human tissues up to sixty-five centimeters in depth (“Terminal Ballistics”). The M855 will go through about thirty-four centimeters of tissue (“Terminal Ballistics”). Since at least twenty-seven to thirty centimeters of penetration are needed, the M855 does the job with due diligence (“Terminal Ballistics”). In fact, the M855 has one up on the M80. According to Troy Tiscareno and Tatjana von E., who are ammunition testers and experts for AR15.com, while the M80 will penetrate a steel helmet at long ranges, it will not penetrate the helmet at ranges past 800 meters. The M855, because of bullet construction, is able to penetrate a standard steel helmet at 1300 meters (“AR15.com Ammunition FAQ”). The M855 round is capable of longer-range piercing of enemy helmets and steel plate armor than the M80.

    As an infantryman walks into battle with his combat gear, he must carry enough ammunition to sustain fire for a long time. The standard combat load of ammunition is a minimum of 360 rounds. Since the M855 cartridge is smaller than the M80, not only does the round take up less space in the rifleman’s gear, but also the rifleman is able to carry more of the other gear he needs due to the lessened weight of the ammunition. Often, a rifleman’s load can weigh up to eighty pounds. If he were carrying the M80 instead of the M855, that weight would increase severely.

    Another aspect of the smaller round that makes it more advantageous than the larger one is recoil. Recoil is the kick that a soldier feels when a round is fired from his rifle. The larger the round, the more power it has to have in order to achieve sufficient velocity to be useful at combat distances. The more power a round has, the more recoil the soldier feels from his rifle. Recoil, while tolerable, is not pleasant for the soldier. High recoil also makes the rifle’s muzzle rise a great deal. The lower the recoil, the easier a soldier can follow one shot with another. Since the M855 has less recoil, the soldier is able to put more rounds accurately into the target than with the M80.

    The only downside to the M855 round is that its fragmentation effect is limited to about 200 meters from the rifle because of the drop in velocity of the bullet after 200 meters (“AR15.com Ammunition FAQ”). However, the average combat engagement range for infantry is inside 200 meters. Therefore, the rifleman would still be equipped to deal with threats within combat range. The M80 does not rely on fragmentation but instead on yawing, which is not affected by range. Thus the M80 would be a more effective antipersonnel round at ranges longer than 200 meters. For those threats that are outside combat range, the squad is always equipped with at least one machine gunner. One of the two light machine guns used in the squad is the M240, which fires the M80. For enemy soldiers that are behind vegetation or other light cover, the M855 round may not penetrate the cover due to its ease of destabilization. Once again, having a machine gunner in the squad solves this problem.

    Based on all criteria for a standard issue infantry rifleman’s round, the M855 performs better than its competition, the M80. The M855 excels over the M80 in light armor penetration, terminal ballistics, recoil, and cartridge weight. The two slight disadvantages that the M855 has are not even an issue, since the machine gunner in the squad is able to take care of those two small shortcomings with his own weapon. The M855 is easier to carry into combat, and easier to control in a firefight. It is also better at stopping an enemy soldier, whether he is wearing a steel helmet or not. The best all-around round for the infantry rifleman is the M855.



    cliff notes: the M855 is better.
     
  2. footratfunkface

    footratfunkface New Member

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    oh, my sources. i forgot.

    Fackler, Martin L., M.D. “Patterns of Military Rifle Bullets.” 2002. 27 Apr. 2003.
    Firearms Tactical Institute http://www.fen-net.de/norbert.arnoldi/army/wound.html

    “Terminal Ballistics” 17 May 2002. 16 Apr. 2003. Steyrscout.org http://www.steyrscout.org/terminal.htm

    Tiscareno, Troy, and Tatjana von E. “AR15.com Ammunition FAQ.” Version 2.46 30
    July 2002. 16 Apr. 2003. AR15.com http://www.ammo-oracle.com/#762

    edited to allow you lazy bastards to go to the sites with minimum effort.
     
  3. Ktulu

    Ktulu Guest

    Still not convinced:big grin:
     
  4. footratfunkface

    footratfunkface New Member

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    and believe me, i feel terribly hurt. tell me where my argument is flawed, not that you don't believe it.

    or, come up with your own damn paper, or something that resembles any sort of counter-argument. or, just continue to wallow in your skepticism.
     
  5. footratfunkface

    footratfunkface New Member

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    well, shit, i'm at school now. i'd rather leave it, and hope he misses that one letter in 6 pages of stuff. if i add any markings to it, he's bound to take off for that, or the original error.

    but, keep going at it, because i might use this thing in the future for something else, and i want it rock solid.
     
  6. kellyclan

    kellyclan She only loves you when she's drunk.

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    Initially, i'd suggest that "the only way to kill a man" in paragraph 5 should read "the only way to kill a man instantly" or some such.
     
  7. kellyclan

    kellyclan She only loves you when she's drunk.

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    Looks good otherwise. i still think squads should have designated marksmen with M14s. :big grin:
     
  8. footratfunkface

    footratfunkface New Member

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    yeah, designated marksmen are not a bad idea, and are employed with smaller units like seals, and sniper platoons.

    and yeah, i'm going to change that line. thanks.
     
  9. kellyclan

    kellyclan She only loves you when she's drunk.

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    In the IDF, the designated marksman normally uses a scoped M16 type anywhere from 14.5"-20" barrel (much like the SPR our special forces have recently fallen in love with in Afganistan), a scoped Galil based .308, or you'll see a SR-25 here and there. Usually with 6x optics, the squad DM's function isn't pure "sniper", just something to allow the squad fast, more accurate, more lethal fire at a distance when compared to the rest of the soldiers CAR15's. The role of the DM requires accuracy only sufficient to drop a target, not the surgical precision a true sniper role calls for. The DM also frequently needs a faster second shot capability than a bolt action will allow, hence, the choice of weapons.
     
  10. footratfunkface

    footratfunkface New Member

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    yeah, to expand on kellyclan's point, the DM doesn't need to be capable of sniping, which is the combination of stalking and marksmanship. he only needs to be capable of marksmanship, and at a higher rate of fire. often, since the DM is with a squad, not alone or with a spotter, he is faced with having to engage targets at very close ranges, and needs semi-auto fire. which is why the M1A is a great DM weapon, just expensive to equip as such. my friend, before he sold it, had planned to sink about $2300-2700 into his M1A to get it up to DM capability. instead, he decided to go with tactical carbines and his PSS. the PSS is done, and at about $1700, it's a lot cheaper. two totally different purposes, though.
     
  11. Possum Stomper

    Possum Stomper The Great Bird of the Galaxy

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  12. kellyclan

    kellyclan She only loves you when she's drunk.

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    Mk12 Mod 0 Special Purpose Receiver
    Assembled by Crane, up to 18" barrel, PRI free float hand guard, OPS Inc 2 port brake and can, Leupold optics, built on a M4A1 or M16A1 lower.

    [​IMG]

    [​IMG]
     
    Last edited: May 1, 2003
  13. kellyclan

    kellyclan She only loves you when she's drunk.

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  14. footratfunkface

    footratfunkface New Member

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    what the hell are we doing up this late? or early.
     
  15. Possum Stomper

    Possum Stomper The Great Bird of the Galaxy

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    SPR=:cool:

    what purpose do they serve again, and how many are issued?
     
  16. 7

    7 First comes smiles, then lies. Last is gunfire.

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    After doing the rifle sim and actually getting to "fire" (simulated recoil, they say it kicks more than the real thing actually) an M-16 more than 100 times and being able to get a real feel for them I've been really considering buying one over the summer. After reading up on AR15.com I might even build one, doesnt seem any where near as complicated as I imagined. I'd still like to have a FAL though...
     
  17. footratfunkface

    footratfunkface New Member

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    spr's: not sure how many, or to whom they are issued. but, the purpose, once again, is to be able to lay down accurate single shots, quickly. the designated marksman seems like the smartest choice for issue of these rifles. so, you'd have a DM or two, and they'd have SPR's. that way, they'd be capable of functioning as a normal rifleman, and as a combat marksman.
     
  18. kellyclan

    kellyclan She only loves you when she's drunk.

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    The SPR is pretty much special ops only right now, i haven't seen or heard exact numbers in circulation.

    They're using 3-9x optics and 75-77gr ammo, so you could figure accurate fire out up to 800m or so, but i believe the SPR only called for ranges up to 600m.
     
  19. Possum Stomper

    Possum Stomper The Great Bird of the Galaxy

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    so is there anything else like an SPR?
     
  20. footratfunkface

    footratfunkface New Member

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    the M80 is better ballistically at longer ranges, but for penetration through a steel pot helmet or the standard NATO steel plate, the M855 is better. this is simply because of the steel penetrator in the M855. if the M80 had it, it too would penetrate, and much better, because, yes, it's more powerful. coincidentally, the M80 will also fragment like the M855 if its velocity is upwards of 3000 fps. however, it's not loaded that hot, so it doesn't.

    for accuracy at longer ranges, 7.62 NATO is better than 5.56 NATO, but it's still not the best. .338 Lapua shows one of the best ballistic coefficients, and one of the flattest trajectories. thing is, availability of production ammo and rifles in other calibers is not as great at all. also, weight, recoil, and other characteristics of the round may discourage its use in the field.

    and yes, a sniper would generally use a bolt-action, due to its greater accuracy, which comes from the fact that there is no bolt operating to let gasses out. the spotter, if there is one, would have a SPR or an M21 though, because if they get in a bad situation, a bolt action rifle is no means of self defense.
     
  21. kellyclan

    kellyclan She only loves you when she's drunk.

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    The Navy has their own version SPR (Mk12 Mod1) that uses KAC gear instead of PRI, and the Marines are working on their own version, designated the SAM. i don't recall 100%, but i believe they were going with KAC stuff as well.

    Yes, the .308 is a much better sniper round and you're correct that bolts are far and away preferred for sniping, but the 5.56mm is acceptable for the purposes the SPR is designed for. The SPR retains the advantage of still being a practical and controllable full-auto weapon when ranges drop to 50m or less. It also uses the same caliber and mags, so the DM can carry the same kit and load as everyone else in the group.
     
  22. Possum Stomper

    Possum Stomper The Great Bird of the Galaxy

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    i just read an article saying that the 5.56 round was not lethal enough, mentioning action in afghanistan where supposedly it took several rounds to stop and enemy from attacking
    :dunno:
     
  23. footratfunkface

    footratfunkface New Member

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    oh goodness. the REAL problem is that when in combat, you don't actually know HOW many rounds it took to take a guy down. because you can't see them hit him, and you don't get to go traipsing out on the battlefield to examine his body afterwards.

    so, when you're being shot at, and you're shooting back, you're going to miss. a LOT. and you're not going to be able to count rounds or tell where they hit. if you do, you'll die. take those reports with a shaker full of salt. also, a lot of those people being shot at are not the fleshiest of bodies. flesh is really what the round needs to get going. skinny guys don't really cause the fragmentation effect as much as fat guys. some of the other problems are that they're engaging targets with M4's out past 200 yards. out of the 14.5" M4 barrel, M855 will only fragment at 45-50 meters. out of the 20" it'll fragment out to 140-150 meters.

    i'll quote this from the AR15.com ammo FAQ:

     
  24. kellyclan

    kellyclan She only loves you when she's drunk.

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    Agreed, the M855 needs a longer barrel to be effective past 50-75m. It simply doesn't get enough velocity from a 14.5" barrel to be lethal at the 200m+ ranges troops were seeing in Afghanistan.

    Incidentally, many specops troops have been using 77gr Black Hills ammo for long range work instead of the M855.
     
  25. footratfunkface

    footratfunkface New Member

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    yeah, i'd try to get the heaviest bastard bullet i could. the 100 grain rounds have amazing terminal ballistics. they start their yaw withing an inch or two, and penetrate about 12-14". it's pretty damn crazy.
     

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