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Thread: Slugs — Testing How Much They Expand and How Far They Penetrate

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    Lightbulb Slugs — Testing How Much They Expand and How Far They Penetrate

    Slugs — Testing How Much They Expand and How Far They Penetrate



    Slugs for airguns won’t ever replace pellets.

    But they aren’t just a fashion, either.
    Slugs easily cut wind drift by more than half.
    And at longer ranges they hit quarry with twice the energy.

    Those are reasons enough that I want slugs (not the slimy ones, though if they are cured with lemon and served with yam and hot chili peppers, they are quite good!).




    The Benefits of Hollow Points

    But almost all commercially available slugs come as hollow points – and for a reason. The hollow point is supposed to expand upon impact and make a larger permanent wound cavity. This is good if your quarry’s kill zone is rather soft and fleshy, as a bigger wound produces a higher rate of DRT’s (over the F&D’s and R&D’s*). (However, if your quarry’s kill zone is a big head protected by tough bones, penetration is probably more important than expansion.)
    *[F&D = fly & die | R&D = run * die]



    If the hollow point projectile (slug or pellet) increases in diameter, so does the impact area, and so does the volume of crushed tissue as the projectile bullies its way through the quarry – leaving the permanent wound cavity.


    For example: A .22cal projectile (slug or pellet) that expands to .295 increases its impact area by 66%.
    And at that increase, even a 1½"-short wound cavity therefore increases by 85%! 85% more tissue crushed!
    [Metric: A 5.5mm projectile expands to 7.5mm. Even a 4cm-short wound cavity is thereby increased by 85% – resulting in 85% more crushed tissue.]

    Also worth considering is that a blunt tip in all likelihood does more damage than a domed or pointed tip. So, all other things being equal, wadcutters, unexpanded hollow points, and wide open hollow points (in this order) will crush soft tissue more than domed or pointed projectiles (that will tend to slip and slice through tissue).




    What Helps the Hollow Point to Expand

    After seeing the often poor performance of hollow point pellets – I wanted to know what expansion I could expect from hollow point slugs.

    Bob Sterne (HardAir Magazine and GTA) published some very insightful articles and posts about the subject (cf. links).
    https://hardairmagazine.com/ham-colu...t-slug-design/
    https://www.gatewaytoairguns.org/GTA...2#msg155979642


    Just to summarize Bob’s excellent discussion:


    Some of the attributes that support expansion of a slug are as follows:
    • larger HP opening
    • thinner walls of the HP cup
    • softer lead
    • deeper HP cup
    • slits (predetermines tearing points) open the HP in petals
    • harder impact material (animal flesh is softer than play-dough is softer than clay)
    higher impact velocity! (as the tests will show, depending on the impact velocity the HP will “work” – or not expand)




    HP Projectile Tests

    Data on HP slug expansion is still scarce, but in the following posts I’ll share the Projectile Expansion and Penetration Tests .22cal that I’ve found so far.

    Take the test results with a grain of salt (or a 22-grainer of lead if you like). As more test data becomes available some tests results might prove to be too optimistic, or pessimistic.



    Some Benefits of the Test Results for the Shooter

    • You will note in the tests that depending on the impact velocity the HP will “work” – or not expand. Knowing the muzzle velocity of a slug that your gun likes, you can do some simple ballistics to figure out at what the maximum range you still can expect reasonable expansion in the quarry.
    • If you have the choice of several slugs that your gun like, based on the test results you could choose one that has better expansion, or choose a lighter (=faster) slug.
    • If you wanted expansion at farther ranges, you could increase the power of your gun based on your ballistic calculations.



    I thank all the airgunners who have run these sometimes very time-consuming tests, and for putting them out there for us so we could learn from them. THANK YOU!!


    Matthias





    An Overview and Some Background of the Projectile Tests in this Thread


    When sifting through the projectile tests (PT) I decided to leave out play-dough, clay, and water as ballistic mediums as they exaggerate HP expansion. Reading what terminal ballistician have written, I considered ballistic gel, ClearBallistics.com gel, glycerin soap, wet newsprint, and of course… – real quarry (dead or alive)!


    The testers often do not give specific details of their test protocol (which kind of ballistic gel they are using), nor do they give exact data (impact velocity) or measurements (expanded size of the slug). I had to do some ballistic calculations and often measure the proportions of the expanded slugs in the images in order to arrive at the data as presented below.


    All the tests include the following:
    • a test designator, PTXXX (where XXX is a counter; PT = projectile test)
    • the ballistic medium
    • impact velocity, and impact energy
    • expansion and/or penetration (in imperial and metric)
    • source (and notes)
    Last edited by JungleShooter; 12-07-2020 at 03:27 PM.

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    Projectile Tests. PT027. Steve Scialli (AEAC) (2020).
    -Ballistic Gel Calibrated.- 40-41FPE.
    NSA 20.2 @841fps + NSA 17.5 882 + N&N 27 770 + JSB 25 783 + FX 22 823

    LINK (just add www. to the front of this):
    youtube.com/watch?v=SJZNGszt0E4





    Last edited by JungleShooter; 19-07-2020 at 07:01 PM.

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    Projectile Tests. PT021. Donnie Reed (Baker Airguns) (2020).
    -Ballistic Gel.- 46-52FPE.
    H&N 23 @990fps + JSB 25 962 + NSA 23 974 + FX 22 974

    Video: LINK (just add www. to the front of this):
    youtube.com/watch?v=9vlQuaAFBIo
    Text: LINK: https://www.bakerairguns.com/general...gs-first-look/




    Last edited by JungleShooter; 12-07-2020 at 03:30 PM.

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    Projectile Tests. PT028. Steve Scialli (AEAC) (2020).
    -Ballistic Gel Calibrated.- 16-26FPE.
    H&N 27 @658fps + J Dm 763 + NSA 20 737 + Hades 667

    LINK (just add www. to the front of this):
    youtube.com/watch?v=sRyg8kIL-ys


    Last edited by JungleShooter; 12-07-2020 at 03:31 PM.

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    Well I've had a play with .25cal FX hybrid slugs along with Hades & Predator hollow point pellets and had very little expansion (42ftlb)

    These tests, both US & UK are being done at close range, which is utterly pointless

    What does it matter if a pellet/slug expands when shot in to a bucket of water from 6" away if I could sneak up to within 6" of a rabbit I wouldn't need to shoot it I could club it to death

    Show me the expansion at 50+yds (including going through the fur & skin) when 2/3 of that muzzle energy has been expended & it will be of some relevance.

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    Quote Originally Posted by angrybear View Post
    ... utterly pointless...
    From getting up early and seeing these posts I wondered how they would be received - or even deleted.

    It's pure data.

    Data is good.
    P1V1overT1=P2V2overT2

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    angrybear,

    I agree, many tests are being done under the most favorable conditions, that are totally unrealistic to normal hunting.

    For that reason I took the time to calculate both the velocity at impact (and the kinetic energy at impact), so that we can compare apples with apples....
    And that shooters can make a simple ballistic calculation how far their particular rig can be from the quarry and still deliver that velocity that has shown satisfactory expansion.


    One of the big advantages of slugs for hunting is that they loose much less energy/ velocity than pellets – because of their higher BC.
    I was surprised when I tried to calculate how much muzzle velocity I needed to make a hollow point pellet hit quarry with at least 800fps at 40 yards. IT CAN'T BE DONE (without shooting them supersonic/ transonic, where accuracy goes down the gutter).
    Because the pellet looses so much velocity, that even shooting it at the upper velocity limit for pellets, say 950fps, will get me to 30 yards but not 40y: The H&N Baracuda Hunter Extreme (18.52gr), with a for hollow point pellets very high BC of 0.026), shot at 950fps MV, will arrive at 30y with 800fps. And much less than that at 40y: 770fps | at 50y: 730fps | at 60y: 700

    Now compare that to a slug with a BC of 0.060 (very conservative!). Shot at 950fps, it will at 30y still have 880fps | at 40y: 860fps | at 50y: 840 | at 60y: 820


    Great times to be an airgunner (and get a FAC license*).


    Matthias


    *Or you could do as I did -- move away from a country with excessively strict gun laws -- like Germany's 6FPE (7.5J) airgun power limit -- and move to a country where the sky is the limit of the legal airgun power -- like Peru....
    Last edited by JungleShooter; 13-07-2020 at 04:03 AM.

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    An interesting thread, however for legal limit I doubt they will be much use, high power air possibly
    Custom BSA S10 .22 PAX Phoenix Mk 2 .22 Custom Titan Manitou .22 (JB BP) HW77 .22 FWB Sport Mk1 .22 Sharp Ace .22 Crossman 600 .22 Berretta 92 .20 Desert Eagle .177

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    Projectile Tests. PT018.

    GunPowder&AirPower (2019).

    -Ballistic Gel 20% – c. 5cm Thick.- 18,36FPE.

    NSA 23 @842fps + Hades 715




    LINK (just add www. to the front of this):

    youtube.com/watch?v=f6jsPP3Z9Fg




  10. #10
    Unframed Dave's Avatar
    Unframed Dave is offline World pork pie juggling champion three years straight
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    Could I request a photo of you eating cured slug Please.

    My stomach heaves violently thinking about it and I've eaten a lot of weird shit.

    Dave
    Smell my cheese

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    Quote Originally Posted by Unframed Dave View Post
    Could I request a photo of you eating cured slug Please.

    My stomach heaves violently thinking about it and I've eaten a lot of weird shit.

    Dave

    Dave,

    I don't have a pic of the actual eating, but I have a pre-meal photo. Note the 1-Euro coin and the Quarter for size comparison.

    Enjoy. Keep heaving! 😄


    Matthias




  12. #12
    Unframed Dave's Avatar
    Unframed Dave is offline World pork pie juggling champion three years straight
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    That Sir is not a slug. I've eaten plenty of snails. Have to admire your constitution, that is a big bugger.

    Dave
    Smell my cheese

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    I stand corrected.
    I guess I know more about guns than biology. No surprise there.
    The latter always bored me out of my mind. The former kept me up at night — even decades before I owned my first gun.

    Matthias

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    Just a note. I like air rifle slugs. But some of the fx brand have lowered by guns power, which is fac. By as much as 6ftlbs. Reason that they ste very tight fitting.

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    Quote Originally Posted by the growler View Post
    Just a note. I like air rifle slugs. But some of the fx brand have lowered by guns power, which is fac. By as much as 6ftlbs. Reason that they ste very tight fitting.
    IIRC they "lost" something like 5ftlb through my FAC Rapid, at the other extreme they shot at only 7.6ftlb through my Scorpion.

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