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Thread: 5.56 Water Expansion Testing; 55/70gr GMX, 62gr TBBC, 55/64/75gr GDSP

  1. #11
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    Quote Originally Posted by BufordTJustice View Post
    Gold Dot rounds of the 64gr variety have been middling performers in my hunting experience. Often requiring an additional anchoring shot even when the heart has been destroyed. I've not had to do that yet with the GMX rounds. Ever. Even on 250lb hogs and bigger.

    And I've seen several Hornady GMX laminate auto glass tests where zero petals were shed. And I've also seen the 50gr BH load lose petals. I don't think that invalidates either round.


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    It certainly doesn't invalidate either based on such small sample sizes, however it's very well documented that all copper bonded bullets sheer peddles in certain situations. Will one encounter one of those situations happen hunting hogs....most likely no since there isn't any glass or sheet metal involved when hog hunting even though WS6 has posted an example of that happening.

    I've seen a test where a 70gr. TSX and the Hornady loading 70gr. GMX fired into water @ 100yds...the TSX expanded correctly, whereas the GMX sheered off a couple peddles. When you combine all these anecdotal examples with validated testing by experts it shows all copper bullets aren't as reliable in their wounding mechanism (sheering off pedals) as the other top barrier blind SD loads in similar testing.

    Now those tests are for humans, not hogs or game...so perhaps were just crossing wires here. The GMX projectile could very well be a better hunting bullet than those others you listed. I'm just speaking in the context of PD, and the wide array of potential situations one might find themselves in.

  2. #12
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    Quote Originally Posted by ALCOAR View Post
    It certainly doesn't invalidate either based on such small sample sizes, however it's very well documented that all copper bonded bullets sheer peddles in certain situations. Will one encounter one of those situations happen hunting hogs....most likely no since there isn't any glass or sheet metal involved when hog hunting even though WS6 has posted an example of that happening.

    I've seen a test where a 70gr. TSX and the Hornady loading 70gr. GMX fired into water @ 100yds...the TSX expanded correctly, whereas the GMX sheered off a couple peddles. When you combine all these anecdotal examples with validated testing by experts it shows all copper bullets aren't as reliable in their wounding mechanism (sheering off pedals) as the other top barrier blind SD loads in similar testing.

    Now those tests are for humans, not hogs or game...so perhaps were just crossing wires here. The GMX projectile could very well be a better hunting bullet than those others you listed. I'm just speaking in the context of PD, and the wide array of potential situations one might find themselves in.
    I don't agree with any of that.

    "Very well documented"?

    No, it's not.


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  3. #13
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    I guess we'll have to agree to disagree. Documented means just that, tests or occurrences showing where it's failed fwiw.

    Nonetheless, I wanted to present a counter argument to your assertation that Hornady GMX loads were head and shoulders above the GDSP loads in the context of actual self defense for those that might read this thread in the future. It's up to them to then research expert opinions on this matter like Dr. Gary Roberts to make up their own mind on this subject.

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    5.56 Water Expansion Testing; 55/70gr GMX, 62gr TBBC, 55/64/75gr GDSP

    Quote Originally Posted by ALCOAR View Post
    I guess we'll have to agree to disagree. Documented means just that, tests or occurrences showing where it's failed fwiw.

    Nonetheless, I wanted to present a counter argument to your assertation that Hornady GMX loads were head and shoulders above the GDSP loads in the context of actual self defense for those that might read this thread in the future. It's up to them to then research expert opinions on this matter like Dr. Gary Roberts to make up their own mind on this subject.
    Still no.

    I've been carefully studying Doc Roberts' body of work since before his first NDIA presentation. I don't get lectured on his work.

    Further, you seem blissfully unaware that there are occurrences of literally every single modern projectile design failing to perform as intended. However, in careful consideration of our delicate casual or neophyte readers, the impression created by your statement that these occurrences are statistically relevant to the discussion are dangerously incorrect.

    In clear terms of the overall percentage mass lost through auto glass, there is very little mathematical difference between homogeneous solids and bonded lead core projectiles; they both lose mass when traversing barriers such as laminate auto glass. Further, the occasional shedding of petals has not shown to have a meaningful difference in terminal effectiveness after the barrier aside from increasing penetration by an inch or two. With notable exceptions like the USMC SOST non Bonded round by federal/atk.

    Lastly, you have not accurately stated my assertions. And they don't need restating; see my original posts.





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    Last edited by BufordTJustice; 11-25-18 at 21:33.
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  5. #15
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    Quote Originally Posted by BufordTJustice View Post
    I remember the first time you documented that. There just had to be a bad batch of projectiles. Mine are first gen 70gr GMX and I've not yet seen a sheared petal on a recovered projectile. But you've been documenting your issues for a couple years now. I can't explain it.


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    This projectile was sent to me directly by Black Hills a couple of months ago. It was not defunct, defective, or otherwise an issue. It was not from the same batch my other issues stemmed from, nor have i had petal shedding from this run. Other bullets (4 from this same box) used to kill deer resulted in perfect and dramatic performance.

    20181121_092555.jpg
    20181121_092442.jpg
    20181121_092419.jpg
    20181121_092627.jpg
    20181121_092658.jpg


    Now compare those entrance and exits at 23m, fired from a 14.5 to he abovee performance, at 120m or so, fired from a 16.1, especially! The punctuate and nontraumatic entrance. I feel this round failed to expand for whatever reason, and yawed (remember, it was a near perfect broadside shot, and impacted near the middle of the animal yet came out the front arm pit nearly...120m is well within its envlope from a 16.1

    I dont have it pictured, but the inside of the rib cage showed a near .224 hole on the entrance side. See above, and the entrance is near nickel sized on my buck. I maintain that expansion failed.
    Last edited by WS6; 11-25-18 at 23:45.

  6. #16
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    Quote Originally Posted by ALCOAR View Post
    It certainly doesn't invalidate either based on such small sample sizes, however it's very well documented that all copper bonded bullets sheer peddles in certain situations. Will one encounter one of those situations happen hunting hogs....most likely no since there isn't any glass or sheet metal involved when hog hunting even though WS6 has posted an example of that happening.

    I've seen a test where a 70gr. TSX and the Hornady loading 70gr. GMX fired into water @ 100yds...the TSX expanded correctly, whereas the GMX sheered off a couple peddles. When you combine all these anecdotal examples with validated testing by experts it shows all copper bullets aren't as reliable in their wounding mechanism (sheering off pedals) as the other top barrier blind SD loads in similar testing.

    Now those tests are for humans, not hogs or game...so perhaps were just crossing wires here. The GMX projectile could very well be a better hunting bullet than those others you listed. I'm just speaking in the context of PD, and the wide array of potential situations one might find themselves in.
    That was my test with the GMX. Today's 70gr GMX is not that GMX.

  7. #17
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    Buford, your projectiles look like oooollldddd stuff. Like, way old. The stuff i tested previous that shed petals was newer. This last batch im testing is yet the latest revision. Compare this round, fired at something like 40m from a 14.5 (impact at around 2700ish) on water jugs to yours. This is latest gen for this projectile. Screenshot_20181125-224845_Messenger.jpg

  8. #18
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    Nice write-up!

    How do you the performance hold up from a VERY short barrels?
    Black River Tactical
    BRT OPTIMUM Barrels - 16" MPR, 14.5" MPC, 11.5" CQB, 9" PDW
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    BRT MarkBlue Gas Tubes - BRT EXT, EXC and PDW Lengths
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    BRT MicroTUNE Adjustable Gas Blocks
    BRT CustomTUNE Gas Ports

  9. #19
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    Quote Originally Posted by BufordTJustice View Post
    I already knew all of that. Hence my disclaimer in the very first post in this thread.

    I've tested varmint rounds and they are actually vastly less spectacular than you'd think, with the amount of damage to the jugs being in much more direct proportion to their real world wounding ability (less than stellar) than you'd think.

    I've done extensive terminal ballistic research on all of these, and hunted hogs with all but the 75gr and 55gr gold Dot. And, I'm here to tell you that there is a rough correlation with my unscientific observations and my experience hunting wild hogs.


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    I know you're one of the more informed people on terminal ballistics and bullet selection, just throwing it out there since other people might not fully understand what you meant by the warning: "it is NOT a tissue stimulant." A naive reader of your post may very well conclude that "more explody = deadlier bullet" which is not necessarily the case.


    I do appreciate you sharing this data though my conclusions would probably differ. When I look at water jug testing I mainly look at the end state of the bullet ie. how much it expanded and how many jugs it penetrated. Ive noticed higher velocity or "hotter" loads tend to produce more dramatic effects in water which is counter to the fact that velocity is NOT a wounding mechanism.

    Recently after sifting through more of the academic journals from Fackler et al. and listening to some of the more recent DocGKR stuff Im starting to devalue temporary cavity more and more. Funny, the deeper down the rabbit hole of terminal ballistics I go, the more I realize you just poking a hole and all the arguments about TSX vs GMX vs Gold Dot matters very little reality and this is all just a fun and educational exercise in minutiae.
    Last edited by vicious_cb; 11-26-18 at 01:26.

  10. #20
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    Quote Originally Posted by vicious_cb View Post
    I know you're one of the more informed people on terminal ballistics and bullet selection, just throwing it out there since other people might not fully understand what you meant by the warning: "it is NOT a tissue stimulant." A naive reader of your post may very well conclude that "more explody = deadlier bullet" which is not necessarily the case.


    I do appreciate you sharing this data though my conclusions would probably differ. When I look at water jug testing I mainly look at the end state of the bullet ie. how much it expanded and how many jugs it penetrated. Ive noticed higher velocity or "hotter" loads tend to produce more dramatic effects in water which is counter to the fact that velocity is NOT a wounding mechanism.

    Recently after sifting through more of the academic journals from Fackler et al. and listening to some of the more recent DocGKR stuff Im starting to devalue temporary cavity more and more. Funny, the deeper down the rabbit hole of terminal ballistics I go, the more I realize you just poking a hole and all the arguments about TSX vs GMX vs Gold Dot matters very little reality and this is all just a fun and educational exercise in minutiae.
    Velocity IS a wounding mechanism at 1800+. It contributes greatly to secondary projectiles as well. As a matter of fact, this doe (shot with 70gr gmx by me at 78m) had secondary projectiles all through the top 3" of her lungs from her spinal column. Further, expanded bullet shape, etc. Does matter. A large flat meplat will destroy tissue more than a rounded one. Especially at the latter portion of the wound tract. My ra556b at 27m (pix on harddrive, not phone) produced significantly less damage than my 70gr gmx at 23m, from a shorter (14.5 vs 16.1) barrel on the exit side. Very interesting about bullet shape, weight, etc.. the wounds look like they cam from different caliber weapons, and you can see the value of retaining velocity through the target. Lots of blood trail on the 70gmx, none really on ra556b.

    20181116_080442.jpg
    20181116_070550.jpg
    Last edited by WS6; 11-26-18 at 08:28.

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