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Thread: 5.56x45 "ill-suited"

  1. #1

    Default 5.56x45 "ill-suited"

    http://news.yahoo.com/s/ap/20080527/...g_over_bullets

    I agree with much of this article but I'm really having a hard time with their barrel length argument when you consider close range and FMJ bullets. At CQB range with FMJs I don't see how there would be any sort of measurable performance difference between the 14.5" and 20" barrels. I love how the term "stopping power" is thrown around. I think the last sentence of the article pretty much sums up the controversy. What say you?

  2. #2
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    Default We have come full circle...

    The 5.56 gets its energy from high velocity. The 20 inch version does. The bullet has very little momentum and when velocity decays with distance or in the case with the 14.5" barrels it just doesn't have the oomph (That's a technical term) of a larger heavier projectile. It will never be a 7.62x51. In the Vietnam era the bullet for the 5.56 was a 55 grain cannelured FMJ spitzer. The cannelure was cut quite deep and this bullet when it hit at high velocity (close range) it often broke in half and created two seperate wound channels. Any FMJ will loose stability at impact and yaw off its intended course and that is what the little 55 grain spitzer did because the twist rate (1 in 12) was not enough to stabilize through the media of human tissue. (This the reason for the Army instructors comments about the bullet tumbling) This M855 penetrator round is better stabilized and much stronger constructed. It doesn't yaw and it doesn't break up, it punches through.

    The good doctor is wrong about the fragmenting of this projectile but he is right about the higher velocity making a greater wound cavity. With impact velocity at about 2800 fps or more there will be significant wounding from the high velocity making a large enough wound cavity in soft tissue caused from stretching and tearing. When the velocity drops so does the wounding ability of this 22 caliber bullet. Some refer to this as hydrostatic shock or simply shock. It is caused by the pressure wave of air compressed in front of the bullet at impact. It can be quite significant but velocity must be high to make it work. Also as we increase the diameter of the projectile it needs less velocity to make the same effect.

    A more frangible bullet would make a greater wound but may not penetrate well. It would seem to me that there are on the shelf several rounds that would be an improvement over the short barreled M4 simply by going to a larger diameter. There exist a 243 on the 223 case (6x45) and the 6x47 (222 mag case) and even a 6.5x45 or 47. These would trade velocity for bullet weight and mass but would perform much better in the 14.5 " barrel than the 223. Certainly the 6.5 Grendel is a winner and could be housed in the same receiver as the 5.56. If we go the the 7.62x51 platform there are a myriad of possibilities that would all be a great improvement over the 5.56 as a military round.

    The old M14 round was and is a much better performer in field and battle than the M16 round. The M16 ammo belt is much lighter giving the soldier the ability to carry a lighter rifle and lots more ammo. Also, it is easier to train troops to deliver accurate fire with the M16 than it is with the heavier recoiling M14. We cannot have the best of both worlds. Carry a big stick or several smaller switches.

    In the CQB arena, especially for the door knockers, they would be much better served with a throttled-up 45 ACP in a fast handling and rapid firing carbine than with the short barreled 5.56 and the M855 round. I was out the day the ordinance department called for my input on this system but I am schooled in the judicious application of lethal force and have experience with same, exercising extreme prejudice.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



  3. #3

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    Yeah, I agree there are a myriad of better choices than the good old 5.56 such as the 6.5's you mentioned and the 6.8 SPC. Of course the 7.62x51 is great but it requires a different platform, has greater recoil, etc. It seems that the 6.5 / 6.8 m4 style carbine would be ideal. Anyway, you mentioned "hydrostatic shock." Do you think there is a significant difference between 2700 and 2900 fps with the M855 ammo? Especially considering that fragmentation is basically a non-issue with this round. It would be interesting to see some data and ballistics tests on the subject. I'm sure it's been done, I just haven't seen the data.

  4. #4

    Default

    Well, I just found more info on 5.56 ammo than I could possibly want.

    http://www.ammo-oracle.com/body.htm

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    Default

    Yeah, that's an informative site.

    The velocity vs hydrostatic shock is really a function of mach three or as the bullet approaches that magical velocity. (It is about mach three for human/animal soft tissue) the pressure wave grows with velocity and from all the millions of rounds of testing a nd forensic study we come to a velocity, with that projectile (SS 109) and a velocity minimum which will deliver the most effective permanant wound cavity. That is about 2800 fps. The 855 ammo was supposed to deliver 2800 fps from a 14.5" barrel. It really doesn't do that and as distance increases its failing becomes more pronounced. That is the reason for the 62 grains rather than 60 or 65 grains becouse the pressure limits, functionality and velocity from the 14.5" barrel was to reach that mystical 2800 fps to make the little 22 caliber round most effective. That of course was the result of too many compromises. The lightly constructed, poorly stabilized bullets of the 1960's would be better in the M-16's for most of this CQB.

    When we were allied with many European nations to ward off the evil empire we all wanted to shoot the same ammo so we came to this sort of agreement. we can shoot our ammo and their ammo. They can shoot their ammo and our ammo. None of these situations are the best but the bullet leaves the barrel without much trouble.
    Last edited by Murphy; 05-27-2008 at 14:27.
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    Moderator LuJon's Avatar
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    Default

    I have seen guys survive 11 rounds from a vulcan cannon and I have seen others die from a single 5.56 so the old addage shot placement rings true regardless of what you are hunting!
    I am not sure what ammo is available but I am set on getting a flat top AR in the 16" barrel for snowmacine based predator hunting this comming year. I am focused on getting a dpma sportical and would like to be able to fataly hit within a couple "minutes of wolf" out to a couple hundred yards with a round that will not tear up the hide. Any ideas.
    While we are on the AR topic any idea about how the 6mm AR would hold up?

  7. #7

    Default 6mm TCU

    Quote Originally Posted by LuJon View Post
    I have seen guys survive 11 rounds from a vulcan cannon and I have seen others die from a single 5.56 so the old addage shot placement rings true regardless of what you are hunting!
    I am not sure what ammo is available but I am set on getting a flat top AR in the 16" barrel for snowmacine based predator hunting this comming year. I am focused on getting a dpma sportical and would like to be able to fataly hit within a couple "minutes of wolf" out to a couple hundred yards with a round that will not tear up the hide. Any ideas.
    While we are on the AR topic any idea about how the 6mm AR would hold up?
    Just check out the 6mm, 25, 6.5, rounds by Thompson Center Arms. The TCU rounds were designed for use in the 14" contender barrel for IHMSA competition and worked well in that role. The 6.5 TCU would take a 50# steel target off a rail at 400 meters from a pistol with a 10" barrel. The main difference was the shoulder angle changed for the SS pistol. Dies are still available for the TCU calibers.
    These were the precurser to the 6.8 SPC we see today.
    The original being I believe a 6x47 used by Remington Arms Designer "Mike Walker" as a benchrest cartridge and was replaced by the PPC line.
    The 6x47 was a commercially loaded cartridge until around 1990 when Remington dropped the 222 Rem Mag as well.
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    Default

    Quote Originally Posted by LuJon View Post
    I have seen guys survive 11 rounds from a vulcan cannon and I have seen others die from a single 5.56 so the old addage shot placement rings true regardless of what you are hunting!
    I am not sure what ammo is available but I am set on getting a flat top AR in the 16" barrel for snowmacine based predator hunting this comming year. I am focused on getting a dpma sportical and would like to be able to fataly hit within a couple "minutes of wolf" out to a couple hundred yards with a round that will not tear up the hide. Any ideas.
    While we are on the AR topic any idea about how the 6mm AR would hold up?
    You should look into the 6.5 Grendel. This is the 7.62x39 case or the 6PPC round necked to 6.5 (.264" bullets) with some minor changes, is designed by Alexander Arms. There is an assortment of good .264 bullets available off the shelf for it in the 108 to 130 grain range both match and hunting softpoints. It will give almost twice the on target effect as any of the 223 loadings. These guns (AR platform) from Alexander Arms can be had in the light weight easy carry to the 24" match version with stainless match barrels. Accuracy is in the .5 MOA and better (as can be had with the good AR's and 223 or Wylde chambers) and field performance out classes the 22 bores. The ballistics are about 115 grains at 2650 from 16" tubes. That gives a PBR of wolf at about 300 yards.
    Is there nothing so sacred on this earth that you aren't willing to kill or die for?



  9. #9

    Default

    The article did not mention field reports for the 5.56 Mk262 Mod 0 or Mod 1, which uses 77 Grain bullets. Seems to be one answer for the M4 lethality discussion.

  10. #10

    Default Nope

    Quote Originally Posted by allen-ak View Post
    The article did not mention field reports for the 5.56 Mk262 Mod 0 or Mod 1, which uses 77 Grain bullets. Seems to be one answer for the M4 lethality discussion.
    Until the barrel gets back to around 18 or so inches all a 77 grn 223 caliber projectile will do is eat up more case space and further reduce velocity and performance. Once a cartridge achieves maximum COL the bullet has to intrude into to case.
    The increase in diameter allows the bullet to be shorter and heavier for the same length, plus reduces the amount of case space it requires, increasing case capacity and velocity; provided you have enough barrel to burn the extra powder.
    However you would think after 40 plus years in service the M16 would have the bugs and kinks worked out by now,As our nations longest running MBR it should be ready for retirement by now.
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    Member AKRoadkill's Avatar
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    Quote Originally Posted by LuJon View Post
    I have seen guys survive 11 rounds from a vulcan cannon and I have seen others die from a single 5.56 so the old addage shot placement rings true regardless of what you are hunting!
    I am not sure what ammo is available but I am set on getting a flat top AR in the 16" barrel for snowmacine based predator hunting this comming year. I am focused on getting a dpma sportical and would like to be able to fataly hit within a couple "minutes of wolf" out to a couple hundred yards with a round that will not tear up the hide. Any ideas.
    While we are on the AR topic any idea about how the 6mm AR would hold up?
    LuJon,
    You might also want to take a look at Rock River Arms. My 24" Varmint model is very accurate. I'm thinking it would be great for wolves out to 200 yards and beyond, and shouldn't tear up much hide. The 24" bull barrel might be a bit cumbersome on a snowmobile, but they make 'em with shorter barrels, too.

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    Default

    Quote Originally Posted by allen-ak View Post
    The article did not mention field reports for the 5.56 Mk262 Mod 0 or Mod 1, which uses 77 Grain bullets. Seems to be one answer for the M4 lethality discussion.
    That would make things worse! Penetration is not the major problem. its putting small holes in your target. the smaller 55grn bullets out of a 20" barrel would make a very nasty wound up close. the M-16 generation of weapons were designed for Vietnam type warfare. Spray and pray. Ammo supply was huge. they have done so many mods to the M-16 that i would NOT want to take on into combat. Give my an M-14 anytime! In afgahnistan the Marines and Rangers are using every M-14 they can get thier hands on as the M-16 types are worthless at long range.

  13. #13

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    Quote Originally Posted by kgpcr View Post
    That would make things worse!
    Not according to testing! There is a blurb on the mk262 not too far down this page. http://www.ammo-oracle.com/body.htm

    Apparently, the heavier bullet fragments easier at lower velocities and is particularly well suited for barrels down to 10.5 inches. So why isn't it in more widespread use??? Good question! Especially considering that the 1:7 twist in the M4 would work pretty well with this weight. I blame NATO!

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    Quote Originally Posted by akav8r View Post
    Not according to testing! There is a blurb on the mk262 not too far down this page. http://www.ammo-oracle.com/body.htm

    Apparently, the heavier bullet fragments easier at lower velocities and is particularly well suited for barrels down to 10.5 inches. So why isn't it in more widespread use??? Good question! Especially considering that the 1:7 twist in the M4 would work pretty well with this weight. I blame NATO!
    QFT

    I use 75gr Hornady TAP in my home defense AR-15 outfitted with a 16" long Operator barrel from Denny's Guns/ Global Tactical. It has a 1/7" twist rate and Denny told me himself that I would get best results using the 75 gr TAP. After shooting for groups I have to agree it is very accurate, and TAP is made for human targets...

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    Quote Originally Posted by akav8r View Post
    Not according to testing! There is a blurb on the mk262 not too far down this page. http://www.ammo-oracle.com/body.htm

    Apparently, the heavier bullet fragments easier at lower velocities and is particularly well suited for barrels down to 10.5 inches. So why isn't it in more widespread use??? Good question! Especially considering that the 1:7 twist in the M4 would work pretty well with this weight. I blame NATO!
    A 77 grain from the 5.56 if fully encased (FMJ) will not likely fragment or expand. If we use soft point or bullets tipped to accelerate expansion the higher impact energy will fragment/expand the fastest. The law of deminishing returns comes into play at some point as we push the heavier and heavier 22 caliber bullets. The bullet weight that gives the highest energy from the barrel length in use will determine the winner if we all use the same type of bullet. Energy is a product of V^2 and m/2. V is a function of barrel length since we are just using the same powder canister and the same pressure envelope. I can't speak to the which bullet weight is better synopsis but the M855 was designed to do a certain job (penetrate body armour) and the more frangible 55 grain cannelured projectile was designed for another. The rifle was designed to deliver a certain bullet/velocity level with a 20" barrel. Velocity was a key part of the performance envelope of the M-16. Shortening the barrrel to, in some cases, as short as 10.5", gives up so much velocity that the package of rifle/cartridge/bullet was degraded to the point of almost worthless.

    I guess we could also blame the Hague convention (if that's who did this) for the "no expanding bullets" for we could improve the performance of the 5.56 as a pasture poodle round with some Nosler BT's or Sierra Blitze bullets.

    If we want to use a very short 10" barreled rifle, if that's what it still is, the 5.56 is certainly not the most effective round in that configuration. Would the 6,8 SPC be better? I think so. Would the other calibers on the 223 case be more effective, I think some would be but marginally so. I think the real answer here, for these door knockers, would be something more in line with the handgun calibers. An M1928 Thompson comes to mind here. I think also that there is no one gun that can do it all. A battle rifle isn't a sub gun, and this Sturm Gewehr is neither.

    A problem for our military is that we fought so hard to convince the rest of the world (our allies, and our enemies in a different way) that the 5.56 was the greatest thing since sliced bread and they were convinced, they all bought it. We are now bound to keep it as our "official weapon" so we can all share ammo, etc. Similar to the M92 being the "official" sidearm and the 9x19 the "official" sidearm caliber. We as a group of countries are bound to support each other with arms and ammo and the commonality of arms and ammo is a necessity here.

    There are many U.S. military troops that are moving away from the 5.56 and the 9x19 because it is less effective than the previous arms and in some cases they are experimenting with other alternative weapon systems. The SOCOM group has the aility to freelance and the money to dabble in this sort of experimentation. I don't know why we came up with the 6.8 SPC. This is based on an obsolete caliber (30 Remington) and then it is shortened so the COAL will fit the AR platform. It's performace is marginally better and there is little or no additional training involved in its use, (it's just a different upper and magazine). Only the logistics of getting the right ammo to the right gun issues are there to sort out. What I don't understand about the selection of that round is likey explained through politics. Why a .277" bullet? Why not one of the existant 6mm or 6.5's that would fit the physical requirements? I also think we would be better off with a 12" barrel on our AR-10 than a 14" on a AR-15. The truth is that the little cartridge developed in 1943 for just this exact same purpose is still a much better choice than the current emasculated 5.56. We can't use that can we? Aren't the bad guys are using that one?
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    The 6.8 SPC has already been rejected by the Government. The Grendel 6.5 is still being looked at.

    The chance of the 5.56 NATO of going away, reminds me of the 7.62 NATO and the demise of the 30-06 GOVT. It ain't going to happen soon.

    I'm working on the Grendel and that is where my focus has been for the past 6 or 7 months. We are just now getting data back on the different barrel lengths and are working with just a few different powders and a few different bullets.

    The vary critical element is twist and barrel length. Like many variation on the 6.5mm. Length bullets, you have to be right on the money with twist for the intended velocity.

    Current project is a barrel that will finish with brake at 16.25". I feel that Bill Alexander has it right with his 6.5 Grendel. I do feel that it's about all your gong to be able to wring out of the limitations on the AR platform, for a number of reasons. Pressure is the biggest limiting factor with the AR. Magazine length is next.

    I like this ctg for the AR it does come off as a vary fine ctg. This year will tell the tale on caribou, this is the reason I have been working with this case. The limitations with the 5.56 in the wind, have really caused me to look out for a better ctg. I do not at this time see any limits out to 600 yards with this ctg on caribou. However the only real proof with be how well it kills out to that distance.

    Big difference in how well something works on flesh as opposed to paper.
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  17. #17

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    <A 77 grain from the 5.56 if fully encased (FMJ) will not likely fragment or expand.>

    Concur, depending on what it hits I guess. I too would expect it not to expand or fragment on people.

    However, the Mk262 is loaded with the Nosler or Sierra HPBT. Mod 0 is not cannelured, Mod1 is cannelured. Not sure how those bullets would act on people compared to the M193 or the M855 round.

    My point is, that the Mk262 round was not mentioned in the original article.

  18. #18

    Default Correct

    Quote Originally Posted by allen-ak View Post
    <A 77 grain from the 5.56 if fully encased (FMJ) will not likely fragment or expand.>

    Concur, depending on what it hits I guess. I too would expect it not to expand or fragment on people.

    However, the Mk262 is loaded with the Nosler or Sierra HPBT. Mod 0 is not cannelured, Mod1 is cannelured. Not sure how those bullets would act on people compared to the M193 or the M855 round.

    My point is, that the Mk262 round was not mentioned in the original article.
    A BULLET designed to expand and cause extreme damage is strictly prohibited by the Hague Convention Treaty.
    So HPBT or Soft point bullets are not even under consideration at this point in time for military use. JUST keep shoot'n them at 4 legged varmints they ain't protected.
    " Americans will never need the 2nd Amendment, until the government tries to take it away."

    On the road of life..... Pot holes keep things interesting !

  19. #19

    Default Murphy

    Since the bad guys are using 7.62x39 maybe we should consider 8mm Kurz for a new assault rifle bringing the assault rifle world full circle. Plus it would be a definate improvement over what we got now for door to door fighting; or maybe a Thompson M1A1 in 38 super.
    " Americans will never need the 2nd Amendment, until the government tries to take it away."

    On the road of life..... Pot holes keep things interesting !

  20. #20

    Default

    Quote Originally Posted by brav01 View Post
    A BULLET designed to expand and cause extreme damage is strictly prohibited by the Hague Convention Treaty.
    So HPBT or Soft point bullets are not even under consideration at this point in time for military use. JUST keep shoot'n them at 4 legged varmints they ain't protected.
    the 7.62 M118LR is loaded with the 175 GR SMK HPBT...that is the round the M40 uses and other sniper 7.62 rifles and designated marksman 7.62 rifles

    I expect the MK262 and the M118LR ammo must have had the JAG sign off on, they are in use.

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