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Thread: What do you think? can a slower bullet knock down better?

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    Member t-storm's Avatar
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    Default What do you think? can a slower bullet knock down better?

    My fall moose hunt raised a few questions about "knockdown power". It started with my moose kill. 150 yds., 340 wby mag., 225grn swift a-frame loaded around 3000 fps. 45" legal(4 brow tines)bull shot right through the middle of the heart. Upon impact, the moose runs about 60 yds. then stops, turns to see what the heck hit him. Another 10 seconds goes by before he starts swaying back and forth. Finaly, like clockwork, drops dead. Fairly ordinary.
    Three days later, my wife shoots a 59" bull at 200+ yds with a 338 federal, the bullet (a-frame) is traveling around 2300 fps at impact and the bull drops like a rock from lung shot. I thought that was somewhat spectacular but I didn't think too much about it untill one day when my son and I were out shooting cans. I'm was using a 22 and the bullet goes right through the can, wobbling it a bit each time. He's using a bb gun and the can goes tumbling off the rock. Now I'm thinking, thats interesting.
    So, other than the luxury of a few inches in trajectory, do you think more "feet per second" is always better? Can there be a majic velocity between 2000 and 2300 fps that knock game sideways? Was my coffee to strong?

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    Member Smokey's Avatar
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    Good Day Tstorm!
    Your thoughts are very valid - there have been some good discussions on here on that matter and a bit of a mixed conclusion at times.
    Here is a bit of a summary as I have seen it...
    A. A slower bullet that leaves all of its energy in the intended target will likely have more of a "knock down" effect than a faster pass thru for sure
    B. The angle of the entry can be the crucial factor when determining ea bullets ultimate effect depending on what was hit - ie; nervous system destruction, bone, etc. Hit the spinal cord with a 22 and it goes down, hit the heart and takes time to bleed out...
    C. when used on living game ea animal is different and what will drop one in its tracks may not have the same effect on the next critter under the same circumstances...
    In a nut shell though I believe the slower bullet of equal size has a knock down advantage vs a faster one that will pass thru.
    I have shot deer with my 4570 - same bullet - 325gn / roughly same size deers / and some dropped - some ran a ways - so far all were pass thru's.
    Take your finger and stick it in your coffee - makes a ripple perhaps - take your finger and push against the outside of the cup with the same force and you can tip it over..
    When asked what state I live in I say "The State of Confusion", better known as IL....

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    Moderator LuJon's Avatar
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    Fill the cans with water then retest your bb gun vs .22.

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    Moderator Paul H's Avatar
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    You can shoot 100 moose with the same exact rifle/bullet combo and see 100 different reactions. Sometimes animals die easy, sometimes they die hard. All you need is a good bullet that will reliable penetrate into the vitals, and a gun that will accurately place them.

    There is absolutely possitively no such thing as knock down power.

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    [QUOTE=Paul H;918848 There is absolutely possitively no such thing as knock down power.[/QUOTE]

    Agreed. Fill up a canvas bag with sand and hang it from a tree with a piece of rope. Shoot at the bag with the meanest big bore you own shooting a soft point so you know the bullet will not exit, expending all the energy in the bag. Watch the bag give a little wiggle. There is your "knock down" power.

    Bet you can make the bag move more by hitting it with a stick.
    Tennessee

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    Moderator LuJon's Avatar
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    Quote Originally Posted by Snowwolfe View Post
    Agreed. Fill up a canvas bag with sand and hang it from a tree with a piece of rope. Shoot at the bag with the meanest big bore you own shooting a soft point so you know the bullet will not exit, expending all the energy in the bag. Watch the bag give a little wiggle. There is your "knock down" power.
    Then shoot a bag just like it with a bullet that WILL penetrate and see which one has the sand drain out of it faster....

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    I think the moral of the story is knockdown power is a myth. You're actually trying to kill the animal quickly by damaging vital systems. Sounds like the wife might just be a better shot
    "When the time comes for a man to look his Maker in the eye, where better could the meeting be held than in the wilderness?"

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    Member Smokey's Avatar
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    Here is some food for thought... I am no scientist but mass x velocity = energy I believe.
    Now, I think the resistance an object has - will determine how much energy is felt/absorbed ???
    Take a gas motor - spark plug fires - energy is created and forces piston to move because its containing the energy of the blast and something has to give - correct?
    Hollow points bullets may be a good example of a bullet designed to transfer the maximum amount of energy upon impact - a full metal jacket bullet can pass through an object creating little energy unless it is contained.
    I have shot milk jugs full of water - no lid and bullets zip through and its hard to tell you even hit the jug - now take same bullet and screw a cap on the jug and because the energy is contained it will likely cause the jug to explode - why because energy was magnified do to containment.
    So, does an animals body contain the energy well enough to create the rise of energy? Well I feel it does and depending on the hit, the animals skin, the bone mass, the bullet type etc it will vary greatly.
    Steel shot on waterfowl is a good example - it can pass through a bird and have a totally different effect than lead shot has at the same velocity...
    I agree 100% though that 100 moose will react 100 different ways - I just think energy release is relevant to resistance.
    When asked what state I live in I say "The State of Confusion", better known as IL....

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    Moderator Paul H's Avatar
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    mass x velocity = momentum
    mass x velocity x velocity = kinetic energy

    Energy is used to do work, in the case of bullet that work is deforming the bullet, destroying tissue, and creating heat. In the case of an internal combustion energy, the hot expanding gasses push on the piston, and also heat the engine, I believe at best 40% of the energy is used to move the piston, the rest is lost as heat.

    Bullet construction affects the shape of the wound cavity. A light constructed bullet will create a large dia shallow wound, a more stoutely constructed bullet will create a smaller dia deeper wound, a solid bullet will create a smaller dia very deep wound, often exiting the animal. The amount of energy delivered by a bullet is less than the energy the rifle exerts on your shoulder in recoil.

    I've shot a 1" thick swinging plate with my 458 lott, 500 gr @ 2300 fps. The stand was relatively light so on impact the plate swung back and lifted the stand the whole thing fell over. Relatively impressive for a firearm, but that plate was maybe 40#'s, and only moved a few feet. Now if a 458 lott can only toss a steel plate a few feet, it is assuredly not going to knock down a 1200# moose. Physics is physics.

    All you can do is destroy tissue and through blood loss the animal dies. If you want to drop it at the shot you have to either make a brain or spine shot. The other option is to take out the front shoulders, death won't be instant, but the animal won't be going anywhere with it's running gear gone.
    Last edited by Paul H; 04-01-2011 at 13:10. Reason: typo

  10. #10

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    Hi All--I just wanted to mention one more area of "knockdown power" that often isn't considered, and that is shock (in the medical sense). The body goes into shock when vital organs are severely injured, and shock can actually shut down the whole nervous system in the presence of enough damage. I have always believed that shock is nature's way of letting animals die without pain when severely injured. In my theory, the brain recognizes that the injury is sufficient to be fatal, and then shuts down the nervous system. When this happens from a violent event, (like a killing shot from a bullet), I believe that the brain can react in shock virtually instantaneously, and can make it appear that the bullet has knocked the animal down.

    Disclaimer: My theory here is just based on my own studies and personal observations, and isn't founded in scientific controlled research.

    Jim

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    Quote Originally Posted by Smokey View Post
    Here is some food for thought... I am no scientist but mass x velocity = energy I believe.
    Now, I think the resistance an object has - will determine how much energy is felt/absorbed ???
    Take a gas motor - spark plug fires - energy is created and forces piston to move because its containing the energy of the blast and something has to give - correct?
    Hollow points bullets may be a good example of a bullet designed to transfer the maximum amount of energy upon impact - a full metal jacket bullet can pass through an object creating little energy unless it is contained.
    I have shot milk jugs full of water - no lid and bullets zip through and its hard to tell you even hit the jug - now take same bullet and screw a cap on the jug and because the energy is contained it will likely cause the jug to explode - why because energy was magnified do to containment.
    So, does an animals body contain the energy well enough to create the rise of energy? Well I feel it does and depending on the hit, the animals skin, the bone mass, the bullet type etc it will vary greatly.
    Steel shot on waterfowl is a good example - it can pass through a bird and have a totally different effect than lead shot has at the same velocity...
    I agree 100% though that 100 moose will react 100 different ways - I just think energy release is relevant to resistance.
    Good en Smokey! Never shoot a moose when his tail is up cuz there will be some energy lost.......and don't stand behind one that his tail up when someone else shoots him......well it's sorta like having a milk jug lid off ain't it!

    I agree with Smokey! I've watched the reaction of probably a thousand coyotes as they take on lead. The ones that get knocked clear off their feet are shot with bullets that spend there energy in the coyote and seldom is there an exit hole. These are usually fast moving thin skinned bullets in small calibers. I have also seen them shot with heavy cast bullet thats barely going faster than I can throw a rock and they just punch a hole with no shock or energy dispersement and the coyote acts like like he wasn't hit. Now if you shoot one with a 7mm Weatherby with a 120 grain boolit there will be an exit hole and he will get knocked of his feet. Lots and lots of scenerios here!

    My very honest opinion is that way more hunters persue big game overgunned than do so undergunned!

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    Member Smokey's Avatar
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    I'm with ya PaulH,
    I don't think a bullet has any energy until it contacts something and then it only delivers said energy at a rate determined by the material it impacts. Stand up a single sheet of paper and bullet zips through stand up a book of paper and bullet knocks it over - resistance magnified power...
    I think "knock down" power is simply a hunting term for absorbed energy and ea animal in our case for hunting will have soooo many factors present that trying to pin a number on its value is really an open book.
    Now, I can understand it also as recoil to the shooter - a big thumper like a 458 bullet pokin along at 2400fps will set me back much harder than a 223 50 grain bullet at 3000fps. I think animals feel the same on the receiving end - yet there are so many intangibles its tough to pin a value on it.
    Now we all have seen some massive internal damage done by energy waves sent out from the bullet - it sure didn't expand and do all that - that expansion of energy is what I would call knock down power.
    But, I am with ya - put one in the neck or head and there won't be any reason to track it! Ker Plunk!
    When asked what state I live in I say "The State of Confusion", better known as IL....

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    Member Smokey's Avatar
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    I've shot a 1" thick swinging plate with my 458 lott, 500 gr @ 2300 fps. The stand was relatively light so on impact the plate swung back and lifted the stand the whole thing fell over. Relatively impressive for a firearm, but that plate was maybe 40#'s, and only moved a few feet. Now if a 458 lott can only toss a steel plate a few feet, it is assuredly not going to knock down a 1200# moose. Physics is physics.

    Ahh, after a 1 hour ride home and breathing in some of that fresh radioactive air I think I had a clear thought!

    Paul, I think your example is exactly what we needed. Now stay with me. To establish a meaningful number to represent "knock down power" we would have to come up with some form of consistent measure. So, lets say we could get a perfectly round steel plate and increase its weight by 1 lb increments. Lets assume we could set it up on a flat surface and no ropes or attachments.
    And, I think we would have to shoot it exactly in the center to avoid leverage changes ???
    So, lets say we can set this 40# plate of impenetrable steel at say 50 yards and shoot it with your 458 Lott and 500 grain bullets and 100% of the time it would knock the plate over. Now if we add 1 more lb and it cannot knock it over 100% of the time we have established (with this way to measure) it has 40lbs of actual knock down power at 50 yards?
    The problem is I don't think on a living creature there is any way to establish a number - however I think its safe to say the 458 would make 100% of any house cats shot at 50 yards go a flyin - that's true knock down power correct? Yet a moose may just collapse - not actually get knocked over for the sake of comparison.
    So I think knockdown power is real - but how do you pin any kind of usable value on it as the live targets are full of variables - you can't IMO.
    When asked what state I live in I say "The State of Confusion", better known as IL....

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    Quote Originally Posted by midnightsunfun View Post
    Hi All--I just wanted to mention one more area of "knockdown power" that often isn't considered, and that is shock (in the medical sense). The body goes into shock when vital organs are severely injured, and shock can actually shut down the whole nervous system in the presence of enough damage. I have always believed that shock is nature's way of letting animals die without pain when severely injured. In my theory, the brain recognizes that the injury is sufficient to be fatal, and then shuts down the nervous system. When this happens from a violent event, (like a killing shot from a bullet), I believe that the brain can react in shock virtually instantaneously, and can make it appear that the bullet has knocked the animal down.

    Disclaimer: My theory here is just based on my own studies and personal observations, and isn't founded in scientific controlled research.

    Jim
    That's interesting.

    Thanks for posting that.

    Smitty of the North
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    This reminds me of the old Jack O'Connor-Elmer Keith fast light bullet vs big slow bullet debates.
    No question a bullet that expands and stays inside the animal is transferring more energy to the target than one that passes though and goes bouncing off into the countryside.The big question is HOW did it transfer that energy-did it shatter into a thousand ineffective pieces and not penetrate or did it shed enough energy though violent frontal expansion to hydro shock the vitals yet retain enough mass to reach the off hide?

    I think, with the jacketed bullets available in the 40s' 50s' and 60's I would have sided with Keith. But with todays partition, bonded bullets we get the best of both worlds-violent expansion and penetration

    As far as animals being "knocked off their feet" I don't believe it's energy transfer from the bullet-I would suspect its a nervous system reaction to the sudden pain, like your arm shooting over your head when you unexpectedly touch a hot stove burner.

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    I agree with jim in that, it is it is HOW the energy is expended, that matters, not how much.

    Expansion always works against penetration, and for that reason alone, over-expansion is to be avoided.

    I prefer to err on the side of penetration, because that is essential.

    I know that there are better constructed boolits nowadays, but I still use heavy for caliber bullets, to help insure they will penetrate enough. For example, a 140 grain bullet in a 280 Rem, may work fine on a Caribou, but what if you need to stop a bear?

    I'm of the opinion that there is shock, associated with velocity, if the velocity is high enough, and it may be due to the vaccum wave behind the bullet that's larger than the bullet's diameter.

    Never having been shot, I can only speculate.

    Smitty of the North
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    Quote Originally Posted by jim in anchorage View Post
    This reminds me of the old Jack O'Connor-Elmer Keith fast light bullet vs big slow bullet debates.
    No question a bullet that expands and stays inside the animal is transferring more energy to the target than one that passes though and goes bouncing off into the countryside.The big question is HOW did it transfer that energy-did it shatter into a thousand ineffective pieces and not penetrate or did it shed enough energy though violent frontal expansion to hydro shock the vitals yet retain enough mass to reach the off hide?

    I think, with the jacketed bullets available in the 40s' 50s' and 60's I would have sided with Keith. But with todays partition, bonded bullets we get the best of both worlds-violent expansion and penetration

    As far as animals being "knocked off their feet" I don't believe it's energy transfer from the bullet-I would suspect its a nervous system reaction to the sudden pain, like your arm shooting over your head when you unexpectedly touch a hot stove burner.
    Jim, just for the sake of friendly what if's, I have sent some prairie dogs doing back flips many times - I think Knocked off their feet" would readily apply and they left their feet before they had any sensation from what was left of their nervous systems. Problem I see is most animals of any size, and with 4 legs to brace themselves, can withstand a pretty healthy blow so we run out of enough power to knock em over quite fast with hand held guns....
    I totally agree with your energy transfer inputs...
    When asked what state I live in I say "The State of Confusion", better known as IL....

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    Shooting animals behind the shoulder is a hold-over from the days of Black-Powder. If it is Meat for the freezer, and you want it dead in a mega-second, shoot it in the brain. Period.

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    Adding to my post #16, and in answer to the OP's question.... "can a slower bullet knock down better?"

    I can believe that sometimes a slower bullet can be a more reliable killer, if over expansion is an issue, because velocity aids expansion, and again, expansion works against penetration.

    I've heard the therory that a high SD bullet, at moderate velocity gives the most reliable terminal performance, and that makes sense to me.

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    Quote Originally Posted by AGL4now View Post
    Shooting animals behind the shoulder is a hold-over from the days of Black-Powder. If it is Meat for the freezer, and you want it dead in a mega-second, shoot it in the brain. Period.
    I think it's more of a practical consideration.

    A head shot is a smaller target, and more difficult to hit, from field shooting positions, at longer ranges. Ya gotta figure the odds.

    If the distance is right for you, and you've got a good steady rest, to shoot from, a head shot might make some sense.

    Smitty of the North
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    Has it ever occurred to you, that Nothing ever occurs to God? Adrien Rodgers.
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