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i am sure some of you have seen my previous posts on here asking about light arrows for elk. anyways i have been comparing small things just to try and convince myself the heavier is better theory is right. for example things like a nut on a bolt or a quarter. most of these things only weight 20-50 grains. i dont know the exact weight of a quarter my scale is not accessible right now. but my point is it doesnt seem that 50 grains would make much difference in penetration on an animal. it is such a small amount of weight. so a 350 grain arrow vs a 400 grain arrow dont seem like it will have a major difference to me. if i threw a quarter at you it would sting when it hit you but if i threw something 50 grains heavier it doesnt seem like it would make much difference in how hard it hit you. I am not saying the guys who swear by heavier arrows are wrong i just want to hear advice and opinions from everyone to convince me of what i keep hearing. thanks ahead of time:confused:
 

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Well think of it this way...its all relative. Yes 50 grains isnt much weight compared to something we weigh in lbs. But if you take 100 grain arrow and add another 100 grains your doubling the weight. Right.
So now take a 100lb wieght and add 100lbs. your still doubling its wieght. . think of how much heavier 200lbs is than 100lbs. With grains, as a human it doesnt seem like all that much becuase we cant really feel the difference. But when it comes to archery adding 50grains here and there can make a huge difference.

good visual example for you would be to shoot an arrow( same arrow) with the same bow. shoot onc with a 100gr field point and one with 125gr. youll see the difference in trajectory.

Now as far as penetration, there is way to many factors that come into play. its hard to say precisley that adding X grains will add X inches of penetration. it has to do with your setup, broadhead used, diameter of arrow,speed..etc

its not a perfect science and i hope i made sense. :mg: But Just plug in numbers to the KE formula and see what ya get. Play around wiith different arrow wieghts and bow speeds and see what numbers ya get.

But in general heavier arrows penetrate more. they maintain more KE downrange.
 

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This thread? http://www.archerytalk.com/vb/showthread.php?t=1045527

350 gr. arrow @ 270 F.P.S. = 57# KE / .42 momentum

Using a 100+ grain heavier arrow (than currently using) won't increase KE by much, but it will improve momentum significantly.

Example: (my bow)
Bowtech SWAT 62# 28'' draw.
470 gr. @ 252 FPS = 66# KE / .52 momentum or 342 gr. @ 291 F.P.S. = 64# KE / .44 momentum.
The heavier arrow carries 2# more KE about a 3% increase (not much).
However, the heavier arrow has over 15% more momentum.

Would a 15% increase in penetration potential be worthwile on an elk? :wink:
 

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Would a 15% increase in penetration potential be worthwile on an elk? :wink:
That's probably a better question than the "50gr" issue.

On whitetails here in NJ, especially when your buck tag is filled, it doesn't make any detectable difference on a 100lb freezer doe. On a 5 1/2+ year old bull elk, it could mean all of the difference in the world. On a freight train size feral hog, ??
 

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A heaver arrow with a mechanical, big cutting edge, big size hard spinning vanes and made off aluminums is not going out penetrate a small carbon, with blazer with a little less helical on them and a cut on impact 1 1/4 to 1 1/2 cutting. It may hit harder, but the bigger cutting edge, vane size with a over spin and the material of the arrows made of will take it or more alway for the hit. When your wanting penetration you got to take every thing into consideration not just the weight. Elk is a big animal. I have blown through 3 bulls with arrow around 400 gr carbons and I hunted with guys who were using big old heavy aluminum who didn't or the arrow broke off on the hit. I had a buddy once shot a cow at 15 yards with a 80 lb compound. The aluminium didn't pass through, but hit so hard the arrow broke into 4 all most equal pieces inside the cow and that way it didn't penetrate for crap.
 

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Well, 20-50gr isn't a huge difference in weight. This year I was testing BH's through 3/4" plywood with my 70lb Old Glory. All my arrows for that bow are pretty heavy.....450gr and up. So I tried a 100gr BH on heavy and light arrows out of my 60lb Commander. 460gr total weight Beman Black Max Elite 340's at 269fps versus 335gr Victory HV 350's at 309fps. At 20 yards, the heavy arrow penetrated the plywood 7". With the light arrow, the tip of the BH barely poked through the backside of the plywood.

Is this a valid test? I don't know, the only difference is the weight and speed of the arrows, and heavy and slow got quite a bit more penetration through plywood with the same BH.
 

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There is some math in a post above and I cannot follow the way it's been done. So in an effort to simplify this I'll redo the math in a format that can make sense to non-engineer folks. (i'm an engineer)

350 grain arrow at 270fps is 56.66 FPE so that is good info
The momentum is 270X350/7000 this is 13.5 pounds of impact force
(there are 7000 grains in a pound so dividing the sum by 7000 puts this into a context that makes sense to people)

470 grain arrow at 252fps is 66.2 FPE
or 16.9 pounds of impact force

The next example is:

342 grain arrow at 291fps
64.3 FPE and 14.2 pounds of impact force


So the impact energy used to drive the arrow into the body is going to be either 16.9 pounds or 14.2 pounds.

10 lbs will drive that arrow through a bull elk, Kudu, wildebeast, gemsbok, zebra, mule deer, Mtn Goat, black bear etc.

It would be light for Bison, eland, giraffe, cape buffalo etc.

for those saying it would be better for a bone impact? No amount is functional for that. better shooting or learning anatomy is the only "real" solution there

The more important question is, how well can you place that 14.2 arrow VS the 16.9 arrow. A well placed shot with 14.2 trumps a less then perfect shot with 16.9. The trajectory difference between these two is the greatest percentage of variance. The lighter arrow will fly with a far flatter trajectory. My 440 grain arrows drop more then a foot at 30 yards when the 340 grain arrows are on the money. without sight adjustment they shoot so much flatter that it's not even a comparison.

There is a point of diminishing returns on this theory. The formulas showing these amounts of impact force are only functional out to about 35 yards for this. You have to understand that weight trumps speed at that distance.

The weight never changes, but the velocity is dropping the whole way. So at some point the speed is reduced but the effects of the weight are still with the arrow. I've noticed this in my 3D targets. Shooting from 20-30 yards the light arrows sink as deep or deeper then the heavy ones. About 40 yards they are equal or random depths too hard to decide due to the area of impact and the amount of times this thing has been hit.

However at 60 yards the heavy arrows are always several inches deeper. Even though they fly through the air like a rainbow! I can see the arrows flying above the back of the 3D deer and they drop right into the body. I cannot see the lighter arrows at all they are too fast, but they do not stick as deep beyond 50-60 yards.
 

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You can also think of it like shooting steel shot at ducks versus hevi shot. Yeah, it might have a bigger initial velocity number but at 35 yards the hevi shot has retained a lot more energy per pellet.
 

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You got to remember a arrow loose energy down range say 40 yard the heaver arrow can retain more energy if it not over spinning. Arrow that is spinning a lot faster will loose energy faster than a arrow thats not spinning as fast. The air is slowing the arrow down faster. Vane size has a lot to do with that to. A feather is faster out of a bow. It's lighter on the arrow and lays down on the shaft out of the bow, but as it gets down range a vane will catch it because feather catch more air and is slowing down faster. A arrow like aluminums witch look like a wet noodle coming out of a bow, also as it hits and will loose a lot of energy. The diameter of the arrow make a difference too a fatter arrow is pushing more air and will loose speed faster slowing it down faster loosing energy. There a good chart that show all this heres a link http://home.att.net/~sajackson/ballistics.html
 

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Agree with OCD and Tman above

I don't think a math equation is going to be conclusive- too many variables.

Look at all of the guys killing deer with soda straw arrows- still works most of the time.

Question is worst case- what will help you increase penetration 1) on a poor shot, 2) elk or heavier critters? Heres whats proven; Coc broadhead with about 3x1 [L x W- I think a bit less is optimal] and heavier arrows.

50 grains is splitting hairs. Will it show on deer- not so much. Ultra light arrows can do all kinds of funny things on impact- all arrows can...but the heavy ones have less problems with this.
 

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I suppose I don't plan for bad shots cause I don't take anything questionable. Sure it can happen nobody is perfect. However setting up a plan "B" is pre-admission of failure.

In my mind when I hunt there is no option to fail. It's success or keep the arrow knocked. No question bad things can happen, but it's not as if I will plan for that.

When you mentally accept a plan "B" it's an automatic plan for failure. Where does this end? Poison tipped arrows, follow up with a firearm, bringing dogs, hunting only high fence, etc etc.

There must be a limit to everything. For me,.... I practice, I use sound equipment, and do not take any risky shots. I've never lost a big game animal living and hunting in South Africa and America We have shot many hundreds of game animals. No risky shots, no lost game, No planning for failure.
 

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it doesn't make any detectable difference on a 100lb freezer doe. On a 5 1/2+ year old bull elk, it could mean all of the difference in the world.
:thumbs_up

A heaver arrow ... mechanical, big cutting edge... hard spinning vanes... aluminums ... small carbon... When your wanting penetration you got to take every thing into consideration not just the weight.
Right, so the "best" arrow would be heavy, skinny, have Blazers, and be topped with a low friction head. Easton FMJ, Blazers, and a Stinger sound good?

There is some math in a post above and I cannot follow the way it's been done.

470 grain arrow at 252fps is 66.2 FPE
or 16.9 pounds of impact force

The next example is:

342 grain arrow at 291fps
64.3 FPE and 14.2 pounds of impact force
I'm not an engineer (or really that good at math) this simple formula was published in Bowhunting World and provides the same result as the calculator that Bowdon put in his reply.

KE is velocity X velocity X weight / 450240
Momentum is velocity X weight / 225120

Either way you got a 16% difference and I said over 15% :cheers:


You got to remember a arrow loose energy down range say 40 yard the heaver arrow can retain more energy if it not over spinning. Arrow that is spinning a lot faster will loose energy faster than a arrow thats not spinning as fast. The air is slowing the arrow down faster. Vane size has a lot to do with that to. A feather is faster out of a bow. It's lighter on the arrow and lays down on the shaft out of the bow, but as it gets down range a vane will catch it because feather catch more air and is slowing down faster. A arrow like aluminums witch look like a wet noodle coming out of a bow, also as it hits and will loose a lot of energy. The diameter of the arrow make a difference too a fatter arrow is pushing more air and will loose speed faster slowing it down faster loosing energy. There a good chart that show all this heres a link http://home.att.net/~sajackson/ballistics.html
In my examples, from my own bow, the heavy arrow is fletched with Blazers and the light arrow has 4'' feathers. The difference in energy retention at 40 yards (using the calculator) is considerable, very much in favor of the Blazers.

I don't think a math equation is going to be conclusive- too many variables.

Look at all of the guys killing deer with soda straw arrows- still works most of the time.

Question is worst case- what will help you increase penetration 1) on a poor shot, 2) elk or heavier critters? Heres whats proven; Coc broadhead with about 3x1 [L x W- I think a bit less is optimal] and heavier arrows.

50 grains is splitting hairs. Will it show on deer- not so much. Ultra light arrows can do all kinds of funny things on impact- all arrows can...but the heavy ones have less problems with this.
I've killed "several" deer with light arrows and mechanicals and a few more with fixed heads. Most of the time my arrows weighed 315-375 grains, had about 60# of KE / .41 momentum. I shot all the deer at 22 yards or less and got a passthrough 19 out of 22 times. However, none of the deer were especially big and the shots were basically broadside at "point blank" range. I anticipated a well placed shot and that's typically what got. However (number 2) I failed to get a passthrough on a turkey and a coyote using the same equipment, under the same conditions. If I can't blow through a skinny 20 yard coyote :mad: regardless of whether I hit the offside shoulder or not, I might want to take steps to enhance penetration. :lightbulb

Beendare is correct, "works most of the time", " Ultra light arrows can do all kinds of funny things on impact- all arrows can...but the heavy ones have less problems with this".

My wife had successfully used 330 grain arrows to get passthrough shots on a couple of broadside 17 yard deer; she had about 36# KE, maybe .34 momentum. In a quest to increase her arrow speed (which of course we need for such close range shots:confused:) I dropped her arrow weight down to about 250 grains, it only cost 2# KE. I failed to consider momentum. She had an arrow deflect off the ribs of a doe that was broadside at 17 yards; this was using a fixed head. The same bow had shot through two deer before, only difference was the arrows were 80 grains heavier. I did not have her just go back to the 330 grain arrows, I increased her to 380 grains. Last year, she hit a deer in the spine and the broadhead penetrated the spine (small doe) and stuck 3'' out the other side of the deer. This is the same bow that deflected a 250 gr. arrow off ribs! Can 80 - 150 grains matter...:doh:
 

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Momentum is speed times weight period, not sure what that 225120 number is or what it adds?

Since we are all working with "grains" as a measure of weight, and there are 7000 grains in a pound, then it makes sense to divide by 7000 so we have a number everyone can grasp in common language.

The Momentum number expressed as a decimal is not a value that can be related to anything but another value. Much like the Kinetic energy mathmatical values.

A bullet with 3000 FP of KE cannot move or lift 3000 lbs. ( not even close) So most people have a distorted view of this value or what it actually means


Using a number that is actual pounds of momentum puts the concepts into a perspective most folks can digest.
 

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:thumbs_up



Right, so the "best" arrow would be heavy, skinny, have Blazers, and be topped with a low friction head. Easton FMJ, Blazers, and a Stinger sound good?

I increased her to 380 grains. Last year, she hit a deer in the spine and the broadhead penetrated the spine (small doe) and stuck 3'' out the other side of the deer. This is the same bow that deflected a 250 gr. arrow off ribs! Can 80 - 150 grains matter...:doh:
Barry,
I'm glad a couple of the debates we had resulted in you getting into HEAVIER arrows....:wink:

No doubt, we all like to have a little speed, and for those of us shooting 70# bows with longer 28+" DL's it's relatively EASY to get decent speed w/ a medium-heavy arrow. Each specific set-up will have a force curve, and on that force curve, there's a point where you can achieve near maximum efficiency of stored energy vs. actual downrange energy. If you can plot that out with your set-up, MOST of us shooting 60+ #'s will find that the weight of that "most efficient" arrow is gonna be upwards of 400gr, and sometimes well above 500gr. Again, it's set-up specific, but we have to decide WHAT specifically we want out of our bows, and make our ammends from that point. For me, it comes down to finding and arrow that works for me, and does what I want it to. The CHEAP arrows I shoot do a great job for me, for others they may not, but for my set-up, the arrows I shoot get the MOST out of my set-up, and deliver quite a WHOP down-range when they hit the target.

I'll take a 500 gr arrow in my set-up over a 350gr arrow EVERY TIME. Also the more efficient we make our set-ups, the less energy your BOW and accessories have to absorb when you let go of that string!!!
 

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Corripe Cervisiam
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Well said ImOcd and SEO...agreed

I suppose I don't plan for bad shots cause I don't take anything questionable. Sure it can happen nobody is perfect. However setting up a plan "B" is pre-admission of failure.
No one I know goes out there "planning to fail" as JJ stated. All of the guys I know spend many hours perfecting their equipment, shooting 3Ds, etc. A guy that maxes out his equipment for penetration- pass throughs- is planning for success even in the worst case scenario.

The only excuse to still be shooting light arrows is flatter trajectory. This compromise leaves you with a a more critical setup, louder shot, softer spined shafts and not reaping the full efficiency of your bow.

"Justifying" to ones self that those 350gr hunting arrows are "as good" as a heavier setup simply is not true- do the research.


..
 

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Those 350 grain arrows will work for elk as long as don't shoot a big expandable. A smaller COC head like the Muzzy, Slick Trick, or Striker will provide adequate penetration on elk with lighter faster arrows. But considering how big elk are, the advantages in trajectory are not as critical as they might be on something like a pronghorn antelope. Most folks out here shoot arrows in the 400 to 450 grain weight range for elk. The Axis FMJ are particularly popular.
 

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This is the beauty of the single pin slider. When you move from 350-375 grain arrows up to 400-440 grain arrows depending upon the game, you simply swap out the sight tape for the arrows your using. Everything else is exactly the same. Same bow, release, sight, just a different aimpoint to use on the sight setting.

Anyhow, that's how I use mine. Shoot 350s for small antelope, warthogs, deer. Then with Elk, kudu, eland, zebra wildbeest, change over to the heavier arrows and the appropriate sight tape.

I believe that the 390 grain weight for my 28.5" Switchback at 62 pounds is as close as possible to bridge the gap. I have shot a lot of weights from 10 to 70 yards and the 390 grain arrows seem to be the sweet spot for trajectory and momentum. I shot that huge cow elk this year from 38 yards with a pass through, she went less then ten feet and laid down to die.

The light 335's are amazing on deer and smaller antelopes. But the 440's are like throwing a spear. Not so much fun to shoot, but drive deep into meat with authority. Where longer shots are expected the 390's seem to give me the best of both for most species.
 

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Corripe Cervisiam
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It a testament to the bow and arrow

how effective it is with whatever configuration you choose to shoot....

...
 
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