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Thread: Water Test: Federal 12-gauge Barnes Expander ¾-ounce slug (P152XT1)

  1. #1

    Water Test: Federal 12-gauge Barnes Expander ¾-ounce slug (P152XT1)

    Federal Premium 12-gauge Barnes Expander ¾-ounce slug (P152XT1) vs. 4 layers of 16-ounce denim

    Average Expanded Diameter: 0.7898 inch
    Retained Mass: 325.4 grains
    Impact Velocity: 1,707 feet per second

    Test Firearm: Remington 11-87; 21'' rifled barrel
    Barrier: 4 layers of 16-ounce cotton denim
    Range: 35 feet
    Test Medium: H2O @ 53° F

    Front:
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    Side:
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    Rear:
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    Predictive Analysis:

    Q-model
    DoP: 20.974 inches
    Wound Mass: 5.060 ounces
    Wound Volume: 8.417 cubic inches

    mTHOR
    DoP: 23.391 inches
    Wound Mass: 5.643 ounces
    Wound Volume: 9.387 cubic inches

    DoP = maximum equivalent depth of penetration in calibrated ordnance gelatin (or soft tissue)
    Wound Mass = total weight of tissue damaged/destroyed within the entire wound channel

    As much as solid copper 'monolithics' have become 'all the rage' in rifle and self-defense handgun ammunition for their improved performance in those platforms, these designs also demonstrate a similar increase shotgun performance. Unlike a lot of lead deer slugs that typically fragment and lose mass along the shot line, copper monolithics tend to retain most, if not all, of their initial mass ensuring that penetration is adequate in the extreme. In this case, the predicted penetration depth, an average of the two models (Q-model and mTHOR), is 22.1825 inches with an average predicted wound mass of ~5.35 ounces or about ⅓ of a pound worth of soft tissue damage matching―and in many cases, exceeding―the performance of many rifle calibers.

    Using the equation for calculating residual projectile velocity in a semi-infinite target (page 19 of Quantitative Ammunition Selection) to model projectile residual velocity by dividing the entire predicted penetration depth into 100 discrete elements (each element being about 5.328 mm thick) to obtain ∆V/∆x, the actual power (in joules per second also called watts) can be determined by dividing the kinetic energy, EK, of the round by the total transit time of the bullet (power is expressed as energy divided by time) through the test medium to the point at which its velocity becomes zero. In order to determine transit time of the bullet, the average retarding force exerted upon the bullet is calculated by using the Work-Energy Theorem, F = ∆EK/∆x, by dividing the change in kinetic energy, ∆EK, over each separate incremental change in distance, ∆x, which allows for the computation of the deceleration of the bullet by dividing the retarding force (F) by the mass (m) of the bullet. Once transit time is computed, dividing EK (in joules) at impact by time yields the power of the bullet in joules per second (watts).

    In this particular test case, the power of the Federal Premium 12-gauge Barnes Expander ¾-ounce slug is 587.4255 kW, instantaneous force at impact is 19.794172 kN (or 4,449.907 lb·f), pressure at impact is 20,416.503 psi and total transit time until the projectile comes to rest (V = 0) is 4.858 milliseconds.

    Of course, the spreadsheet does all of this for me (as seen below), because I am a typical lazy retired cop and not a glutton for mathematical punishment.

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    The red curve shows velocity decay, the blue curve shows EK decay and the black curve shows deceleration decay; all curves are with respect to instantaneous projectile position.

    So, with all other terminal behavior factors remaining the same, power naturally increases proportionally due to the increased braking forces that result from the larger expanded diameter and greater ELOSS of the expanding slug. That power, which is the rate of energy expenditure (or loss) over a given distance, ELOSS/∆x, is what gives rise to and produces the radial displacement of tissues that come into direct contact with the projectile and creates the stresses that damage tissue.
    Last edited by the Schwartz; 03-31-2019 at 04:12 PM.
    ''Politics is for the present, but an equation is for eternity.'' ―Albert Einstein

    Full disclosure per the Pistol-Forum CoC: I am the author of Quantitative Ammunition Selection.

  2. #2
    Site Supporter entropy's Avatar
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    Cliff note version:

    “It ‘aint buffin’ out...”

  3. #3
    Quote Originally Posted by entropy View Post
    Cliff note version:

    “It ‘aint buffin’ out...”
    Nope. "That's gonna leave one helluva mark!'' sure seems to apply here.

    Recoil from this load was pleasingly manageable, too; probably a function of the gas-operated system and the mass of the 11-87. Damn, I love that gun....
    ''Politics is for the present, but an equation is for eternity.'' ―Albert Einstein

    Full disclosure per the Pistol-Forum CoC: I am the author of Quantitative Ammunition Selection.

  4. #4
    Site Supporter entropy's Avatar
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    The last time I looked at a shotgun as a defensive tool, the new era ammo wasn’t even a factor. I need to educate myself a bit on what’s out there now. Your post made me realize how far behind the power curve I am with shotguns. I agree...the 1100 series has always just “fit” me, and it runs like the old Dodge 318ci.

  5. #5

    Warning: Anecdotal sample size of '1' within...

    Quote Originally Posted by entropy View Post
    The last time I looked at a shotgun as a defensive tool, the new era ammo wasn’t even a factor. I need to educate myself a bit on what’s out there now. Your post made me realize how far behind the power curve I am with shotguns. I agree...the 1100 series has always just “fit” me, and it runs like the old Dodge 318ci.
    I would urge you not to discount 'old' ammunition options. Sure, copper slugs are a fine option―especially when launching multiple projectiles (buckshot) might result in striking a downrange innocent―but, if that concern does not exist, buckshot still offers a viable close range (that is, out to 25 yards) option. The rate of fire and moderate recoil that the 1100-series is capable of makes 'controlled doubles' possible with a little training and makes it an authoritative fight-stopper in my opinion.

    In the late 1990s, right after my department transitioned from the Remington 870 to the Remington 11-87, we had an 'on-duty' OIS involving the ''then-new-to-us'' 11-87 using issued Remington Express 12-gauge 2¾'' #1 Buckshot (16 .30-caliber pellets each weighing 40-grains at 1,250 fps)―

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    ―in which an armed-robbery suspect (5'9'', 175-180 lbs.) took two full loads to his lower chest and upper abdomen in about one second at a range of about 8 yards after he pointed a 9mm pistol at an officer. The suspect was instantly neutralized, collapsed to the ground immediately without taking another step or falling backward or forward, just slumped straight down onto himself. Not surprisingly, about ⅔ of the pellets exited the suspect's back since #1 buckshot typically produces 16 - 20 inches of penetration. It is hard to argue against performance like that.

    If your circumstances allow the use of buckshot, why not?
    Last edited by the Schwartz; 04-02-2019 at 02:51 PM.
    ''Politics is for the present, but an equation is for eternity.'' ―Albert Einstein

    Full disclosure per the Pistol-Forum CoC: I am the author of Quantitative Ammunition Selection.

  6. #6
    What advantage does the Barnes copper slug provide over the Brenneke slugs or Federal DPRS on DocKGR's list?
    Wolves don't kill the unlucky deer.

  7. #7
    Quote Originally Posted by David C. View Post
    What advantage does the Barnes copper slug provide over the Brenneke slugs or Federal DPRS on DocKGR's list?
    From the rear end of the gun, a little less perceived/felt recoil―at least using either my well-worn Benelli M2 or Remington 11-87. I suspect that gas operated platforms tend to attenuate recoil to a somewhat greater degree than slide action designs (like the Remington 870), but have not had the chance to see if there is a similardifference with the Barnes offering. The heavier Brenneke loadings (esp, the TKO) tend to really ''back up'' with fervor in both my M2 and 11-87 whereas the Barnes copper slug, despite its higher muzzle velocity, seems to recoil noticeably less. This might also be dependent to some extent upon propellant burn-rates between the two loads, too.

    On the receiving end of the ammunition, there is a slight increase in terminal penetration with the Barnes copper slug.
    ''Politics is for the present, but an equation is for eternity.'' ―Albert Einstein

    Full disclosure per the Pistol-Forum CoC: I am the author of Quantitative Ammunition Selection.

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