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Thread: Terminal ballistics-wise: Mk318 or M855A1?

  1. #11
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    I donít know when the stuff I shot was made, but the ballistics were noticeably different. POI was significantly higher, I assumed due to the increased velocity.


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  2. #12
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    Pressures have been dropped but there are still issues with the M855A1 damaging weapons.

    In regards to terminal ballistics, M855A1 is superior to the MK318. Better penetration, and fragmentation.

    Quote Originally Posted by vicious_cb View Post
    1st of all M855A1 doesnt have increased wear anymore since they dropped the pressures. Both anecdotally and looking at ballistics gel, M855A1 seems to be the superior bullet. They are very close in performance but when the distances increase and velocity falls off, M855A1 looks to have a lower velocity threshold for fragmentation.

  3. #13
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    Quote Originally Posted by ABNAK View Post
    Do you happen to have a link I can read on the subject? I'd be interested to see changes and timeframes.

    I don't recall where I read it but supposedly the pressures weren't dropped all the way back to "regular" 5.56 NATO, but nonetheless lower than the original recipe.
    Noone really knows. It was rapidly evolving in real-time, with multiple lots/charges in circulation at the same time, etc.
    Last edited by WS6; 05-10-19 at 04:41.

  4. #14
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    Quote Originally Posted by davidjinks View Post
    Pressures have been dropped but there are still issues with the M855A1 damaging weapons.

    In regards to terminal ballistics, M855A1 is superior to the MK318. Better penetration, and fragmentation.
    I'm just recalling this off the top of my head but the originals exceeded 60,000 PSI and now they're down to like 56,000, correct? Don't recall where I read it. So less than the original but still higher than NATO specs.
    11C2P '83-'87
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  5. #15
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    Quote Originally Posted by kaltesherz View Post
    Pretty sure the pressure reduction wasn't long after it was introduced after all the reports of breaking bolts and wearing out barrels quickly. All the lots we've been shooting are older (2014ish) and don't seem noticeably hotter than M855.

    M855A1 fragments much further out than green tip, I haven't seen any hard data but from unofficial experiments people have been making with gel I wouldn't be surprised if it was past 300m. It's a huge improvement.
    Its target was 600m initial, but I believe they backed off to 450-500 or something as a more realistic goal with pressure reduction.

  6. #16
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    Quote Originally Posted by ABNAK View Post
    I'm just recalling this off the top of my head but the originals exceeded 60,000 PSI and now they're down to like 56,000, correct? Don't recall where I read it. So less than the original but still higher than NATO specs.
    They're a few hundred PSI lower than greentip, I believe.

  7. #17
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    It’s not so much the pressure anymore, it’s the design of the projectile. Combating the that specific issue is why the .Mil has been updating magazines. However, that’s not the end all be all answer to the issues.

    Quote Originally Posted by ABNAK View Post
    I'm just recalling this off the top of my head but the originals exceeded 60,000 PSI and now they're down to like 56,000, correct? Don't recall where I read it. So less than the original but still higher than NATO specs.

  8. #18
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    Mk 318.....

  9. #19
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    PSI still high. cartage DOES NOT meet NATO/STANAG specs

  10. #20
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    Quote Originally Posted by XUSMICO View Post
    PSI still high. cartage DOES NOT meet NATO/STANAG specs
    My understanding after reading about this round off and on for some time now is that the pressure was dropped rather quickly due to burning out barrels, which was a point the Marines use to fight acceptance, and the only problem it has with current magazines is the tip is not presented quite high enough to not gouge the feed ramps of the barrel extension a bit.

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