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Need help to settle debate

  1. Oct 17, 2012 #1
    Hi Thanks for Taking a look

    Need help to settle a debate (now argument)

    Viewing the "Titles of topic" in this forum, a question such as this
    more than likely will result in an "LOL ! are you kidding me" (why is this here ?)

    But, if you are Mathematically Illiterate.. Trying to show calculated proof for the following
    question is impossible.

    The question: (Verbatim):

    This is more of a fun debate question, but it was something I was thinking about.

    If you have a pointed 8gr .177 pellet traveling at a speed that gives 10
    foot pounds of force, and another pointed 14gr .22 pellet traveling at
    a speed that also gives it 10 foot pounds of force, which is the better
    hunting pellet for small game?



    The above question was "Hypothetically" posted by a forum member (on another forum), as a "Fun" debate.

    Two sides have resulted "Trying to give an answer" to the question..

    Side one:

    No difference "either pellet will do", because Force is Force and both have 10 foot pounds.

    Side two:

    Use the .22 because Bigger is always Better..


    Can any one here assist (Or care to) in showing "Proof" for either result
    to settle (I hope) the debate / argument.

    Take it easy on (Me) with regard to complex mathematical formulation
    as I only have (Basic) High School Physics.. most of which is forgotten.

    All I have been able to calculate using the above (Minimal data) is velocity.

    (.177) 8 grain - velocity 750.25 ft/sec = 10 foot pounds or 13.56 Joules
    (.220) 14 grain - velocity 567.00 ft/sec = 10 foot pounds or 13.56 Joules


    Any way, thanks for reading.

    And I hope all you math whizz's will have fun with this for something to do.

    Please help: (It's a gun forum, and some members have loaded their weapons.) :smile:
    Last edited: Oct 17, 2012
  2. jcsd
  3. Oct 17, 2012 #2
    I think this is up to a biologist to answer. It seems to me the question is asking whether a smaller, deeper hole is preferable to a wider shallower one.

    Thats not really physics, more biology.
  4. Oct 17, 2012 #3
    Thanks vorde..

    (no doubt) Bit of Math, and a bit of Biology..

    Posted here first.. just to see if any one can "Easily" prove that the "Foot Pound" force.
    would arrive at the target (Still being the same) for both sized projectiles.

    Not staying the same as in 10 foot pounds (Not possible)
    but rather (lesser), yet equal. like 5 and 5 or something. (Simply x=y)

    Personally I say they will.. only gut instinct. (but could be wrong)..
    (my guts are my only reliable calculator at this point in time.) :redface:

    If result is (x=y foot pounds) then "Biology Time"
    But there are a lot of (unknown) variables to that scenario as well.


    Unknown values for the first question are "Distance" and "Target"
    just know, they should be the same for both projectiles to be fair
  5. Oct 17, 2012 #4


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    Staff: Mentor

    I don't think "Foot Pound" can be a force. It has units length*mass.
    Even if I use pound-force (which is completely different, and requires the gravitational acceleration earth as reference), the product has the unit length*force = energy.
    Imperial units are complicated anyway ;).

    I would expect that the smaller, faster bullet has a better range and can penetrate an animal easier. If the animal is too small, it might exit at the other side, and deposit less energy inside. But that is really a biology question.
  6. Oct 17, 2012 #5
    I Respect your thoughts regarding "Foot Pounds" not being a force.

    Exactly as you stated "more like Energy" Perhaps look at it as "Energy"
    (or Muzzle energy.)

    The "Foot Pound" and "velocity" rating for airguns is mainly used to determine a "Legal Limit"
    from the stand point of (fire arm regulators.)

    And many airgun users, use these number to determine "Effectiveness" (or most bang for the buck)

    Here is the "link" to the on-line calculator I used to "Calculate" the missing velocity value
    from the original (Hypothetical) question in my first post.


    Details are given how it is calculated (perhaps it will help)

    I await any further thoughts you may have..
  7. Oct 17, 2012 #6


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    mfb: I believe as it is used in ballistics, the foot pound is indeed a unit of energy, since the pound used is the pound force.
  8. Oct 18, 2012 #7
    It doesn't really make sense to say that a projectile gives X amount of force, since the the impact force is not constant. The force /pressure depends on both the shape of the projectile and where it hits.

    I don't really think it will actually make much difference what pellet you use if they hit the same spot. The smaller pellet has a higher chance of piercing trough but in the end the result is the same.
  9. Oct 18, 2012 #8
    Hi cjl & bp_psy

    Please forgive my "use of the wrong word" in my reply to vorde.

    I should have not used the word "Force" but rather energy.

    mfb is correct (it's my error) and confused (mfb) for his reply.:redface:

    I also think the same as you pb_psy that:
    "The smaller pellet has a higher chance of penetration"

    So the result is the same.

    .177 inflicting Penetration injury
    .22 inflicting blunt force trauma

    Same end result I say..

    The "Experienced" shooters make a good argument also..
    with a "Fur or Feathers" argument..

    That is : Feathers are harder to penetrate than fur..
    so for an effective "Guaranteed" kill you must use the .22
    else trying to use the .177 could only result in an
    "injured" not dead animal.

    Energy required for kill is no less than 8 foot pounds.

    Just don't know at what distance the energy would fall below
    the minimum 8 foot pound required. with a .177

    And what distance would it be for .22 to deliver the fatal 8 foot pounds.

    Thank you and I await your further input.
  10. Oct 18, 2012 #9


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    Gold Member

    Your question cannot be settled with the minimal information given.

    Most likely you are relating this to shotgun pellet size for fowl and small game hunting.
    Besides the shot size, the spread of the pellets after they leave barrel of the gun, so as to cover a wider area, increases your chances of a hit, as the animal is moving ( rather than 'motionless' in big game hunting ).

    A smaller shot size means more pellets can be packed into the shell. Larger shot means more range due to air resistance. More charge of gunpowder means more velocity of the pellet(s).

    With that in mind, your best bet would be to look into what shotgun and shot, with charge, are best for hunting a particular animal.
  11. Oct 18, 2012 #10
    I think it is not just the stopping power of each bullet but the range. A .17 has a lighter projectile and a higher muzzle speed so a higher effective range. More accurate is a more likely kill. A .22 will kill as well but the shooter must be more skilled to use it at range. A .22 will expend more energy on the game and will more than likely stay in the game. A .17 is more likely to go through and carry off energy and therefore be less efficient at doing damage than the higher calibre, but for small game will do the job.

    probably doesn't help settle your argument but I think it a matter of preference rather than physics.
  12. Oct 18, 2012 #11
    Code (Text):
    Your question [COLOR="RoyalBlue"][B]cannot be settled[/B][/COLOR] with the minimal information given.
    LOL 256bits you said it.

    And again as you said. because of "minimal information"

    I came here with hopes that some basic "Hypothetical" value of distance could be inserted
    and a "Probability" of effectiveness could be calculated within that distance.

    Or what pellet would carry it's "Effectiveness" the farthest.

    If effectiveness is (8 foot pounds minimum) at what distance does the Foot Pound Energy
    drop to 7.99 ?

    If the .22 can carry that energy "Farther" then it wins

    If, Energy drops to 7.99 for both at the same "Hypothetical' distance..
    then either will do.

    I do know that 8 foot pounds of energy is the "Magic Number"

    So if a "Decay Rate" of "Velocity" could be calculated / Graphed.
    You could use it to recalculate the "Foot Pounds"

    As for relating it to "shotgun pellets" no. (They are .177 and .22 Air Rifle) pellets.


    Thanks JustinRyan

    You and I, see it in the same way.

    You also hit the nail on the head, and find Reason for the Two sides..

    Code (Text):
    I think it a matter of preference rather than physics.
    I can only think "Physics" - My preference
    More of a scientific approach, because I don't hunt.. "I am a marksman"

    I Shoot at competition level.. So knowing what kills is not my bag.

    (The Rifle I use is the "Avani 887 Gold medalist") --

    I shoot 1/4 inch targets (confetti glued to tooth picks) at 100 feet just for fun. :smile:

    Thing is, I have lost my ability for "Computation" over the years..

    If you don't use it, ya loose it.

    ----------- So in a nut shell.

    With the minimal information provided..

    Is it possible to show a "Velocity" decay, to obtain the (fpe) calculations as well.

    Thanks, and await your comments.
  13. Oct 18, 2012 #12
    not sure that could be done without the friction co-efficent for the snub nosed .22 vs the ballistic tipped .17 as they will be different. But I would bet the ballistic tip, (higher velocity & lower friction) would carry the energy further.
  14. Oct 18, 2012 #13
    Yup.. Thought that would come up..

    It's called the "Ballistic" coefficient. or (BC)

    Thing is, the Pellets described in the original question are "Hypothetical" and don't
    quite exist.. (not exact grain weights for the .22)..

    I found some "Relatively" close to described..(pointed).. (And scaled versions of each other)

    They are reported to be "Most nasty" for their size, and shape.

    Sub for the.177

    BC for .177 = .016
    8.0 Grain

    And Sub for the .22

    BC for .22 = 0.025
    16 Grain

    Any other Values (That would / could, or should be needed ?)
    Just ask, and I will try to find them.. (I hope)

  15. Oct 19, 2012 #14
    Better in what sense?

    If the impact force is same in both cases then they both have same momentum, in which case it's useless to do pre-impact calculations. But just to add some facts to the pre-impact events, pointed pellet will experience less aerodynamics drag so effective velocity will be more hence more momentum due to velocity but the other pellet has more mass so it can have more momentum due to mass. But as I said since you stated the impact force is same then they both have same momentum.

    From penetration point of view if both pellets exert same amount of force then the pointed pellets will cause higher sheer stress due to smaller surface area.
  16. Oct 19, 2012 #15


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    Gold Member
    2017 Award

    The very fact that there is a vast range of ordnance specifications, used by the military, tells us that there is really no general answer to the OP. 'It all depends' on what you want your pellet / bullet / shell to achieve and the nature of the target. In the end, you will need a certain amount of energy to do a destructive job and the construction and material that you are trying to damage need to be matched to the mass, shape and speed of the projectile (given a maximum of available energy).
    The actual 'force' available will depend on the time that the projectile takes to slow down. A sharp bullet could penetrate a long way through some soft tissue and slow down, applying a low force, in a long time - doing little serious damage. Another bullet with the same mass and speed could flatten out and slow down much sooner, producing a high, short lived force, resulting in a shock wave through the victim which could kill them by affecting a nearby nerve centre.
  17. Oct 19, 2012 #16
    Thanks Aj83 and sophiecentaur (including all others that have responded above.)

    My views, (as all of you) are the same to the "Simplicity" of the Out come..

    I don't even need to calculate it.. (Just comes second nature) obvious. (As it does to you)


    How ever.. (The other half) who just can't grasp the "Physics", or what is "Hypothetical"
    only give their answer based on "Experience" in shooting.

    State that: ".22" always better..(grunt) "Bigger Better" (grunt)
    When I shoot my .22 it's always better.. (grunt)

    "YAAA WELL".. In a real life situation. (the gun is designed that way..)

    I mean.. Why would a rifle company design a .22 to have the same foot pound energy.
    as a smaller .177.. (NOT going to be in real life.)

    I try to explain "Upside Down, Around, and Backwards" ... and fail..

    With equivalent arguments as yours.

    Trying to point out that the OP's "Hypothetical" question.

    Is just that... "Hypothetical"... and in it's case (Either one will do.)

    But.. Nope..

    (Bigger Better) (grunt)

    It boils down to "Neanderthals against the Intellects" in reasoning.

    I may as well give up.. Even if proof of (Mathematical) or (Charted)
    evidence were presented, they would still not get it.. (or perhaps want to.)

    Sad, and frustrating.. (But as they say "Ignorance is Bliss")
    At least I know what "Hypothetical" means.

    So.. Thank you (every one) for your time.. (Great bunch) of people here..
    Nice to hear from those who can reason. (and with logical thought.)

    I consider the topic of the above "Hypothetical" question now (CLOSED)

    If not for any physics problem, just to maintain my sanity. :smile:

    Again Thanks.


    Was reading some of the other Topics here..
    (Ouch)... (Brain now smoking)... (Grunt)
    Last edited: Oct 19, 2012
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