Shooting Light Arrows

[Swamp Bow]

Well you can take a log and hit something at 3 miles an hour, and then take a feather and bring it up to light speed and get the same result.  That is plain physics.  What is practical in the real world is another matter.  This is purely conjecture, but I suspect that even the "fastest" compounds can't bring some of the super light arrows up to a high enough speed to get the same effect as the "slower" traditional bows with heavy arrows.  The light arrows will fly flatter and get there quicker, but just won't have as much energy left on target.  I have no idea where the line is and it would take a very scientific approach with release machines and the like to get real results.  Then you have to take into account angles and muscle variance for animal to animal even within species...  More than I want to deal with.  Personally, I think it is more practical to use a heavier arrow, up to a point of course.  I also don't want to have to shoot up at an 80* angle to hit a target 20yds away because of arrow drop, or shoot a really heavy draw because the bow spent all of it's energy just getting the arrow going.

Choo-wa-chobee:  I agree.  I'd rather be on the giving end of the 50/70 for one or two shots, but I'd much rather use the .243 if I'm gonna put a few hundred rounds down range.  Just like I'd rather use a 45-50# rather than a 70-80# bow to target shoot all day.  You can use the heavier ones, but ouch.  Always a compromise.

Swamp

[Mechslasher]

my phylosophy is that i want an arrow that will perform in a worst case scenario.  this arrow should be flying a minimum of 150fps, with an foc of at least 15-20% and weight of 500gr.  all these are minimum numbers, imo.  this should give enough momentum to penetrate all but the toughest of bones, in a worst case scenario.  most of the animals i've killed with a bow were not hit where i was aiming, simply because animals move!  eddie can tell ya'll about the first boar i killed at alexacarrie plantation.   released the arrow with him broadside, but the arrow hit him in the jaw with him facing me.   all of the idio...i mean gentlemen that argued always came back to the number of pass throughs they've had on broadside shots using light arrows.  hell, at any point in the respiratory process  the chest cavity is just alot of hot air separated with a bunch of spongy tissue so what wouldn't pass through this?  but what happens when the animal moves, say take a quarter step facing you?  now you are looking at having to punch through the humerous or the shoulder blade, but the arrow is on its way.  the only thing i can think of is that in some parts of this country, animals are rather lazy and move very slow to validate their opinions.

[Kegan]

I'm with you Mechslasher, 500 gr at 150 fps is a good minimum. There are alot of hunters who've killed elk and moose with 500 gr arrows moving at 175+ fps, and obviously heavier arrows have proven their worth more than once!

So far 600 gr is all I can really get out of my arrows at the moment to keep the weight, so I'm just trying to tweak a little more speed from my heavier bows. Nice to be able to shoot the same arrows from bows 65-80# though

[aznboi3644]

one thing to consider...on impact a lighter arrow will flex more and that is lost energy for penetration.

[FlintWalker]

If a 40-45# bow will kill a deer, then let's assume that means with a 400-450 gr. arrow would about be the minimum. So the weight of your arrow is a better indication than just the bow weight, since the arrow can't really accept alot of excess energy, or else we'd all be shooting flight arrows at 200+ fps.

So going up against a scapula with a 350 gr arrow would be like trying to shoot through a shoulder with a 35# bow. And that's not something alot of people will look so kindly on

My evil-shafted-arrows weigh in at 600 gr. so they would have the force of a 60# bow even though I'm shooting 70-80# at the moment. Which I can believe.

  Not necessarily....It's very possible to build a carbon arrow that will finish out at around 300 grains or less, including the point that will spine out at 70 -80 lbs.  So saying a 350 grain arrow can only impart the energy of a 35# bow is not really so.   10 grains of arrow weight doesn't equal 1# of spine stiffness, and the weight of the arrow doesn't  limit the amount of force that can be applied to it, the materail does.
 I'm like Justin in that I don't rely on GPP of draw.     If a 450 grain arrow comming out of a decent performing 45# bow is enough...then that same arrow coming out of a decent performing 60# bow is more than enough.  I also don't think that just because a fella shoots an 80-100# bow, that an 800-100grain arrow is necessary.
 I like arrows in the 500-600 grain range regardless of the bow weight.
 BTW, I've personally seen arrows bounce off a deers scapula

[Little John]

I like heavy arrows from traditional or wood bows but also know that light carbon arrows from high powered compounds will always penetrate deeper into a foam target than nine. About breaking bones on game I dont know. The Asby test were conducted using very heavy bows and they penetrated deeply with the right arrows.  I say to shoot as heavy of a bow as you are comfortable with and can shoot well and with heavy arrows.   Kenneth

[Kegan]

SawFiler- I didn't mean that the you had to follow a 10 gpp formula, that'd make me a complete hypocrit . I just meant that if you're shooting a 300 gr arrow from a 90# bow, it won't be hitting with the full force of a 90# bow. Even though the bow is very heavy, it will be hitting as if you were shooting a lighter draw weight. Of course, how I worded it the first time was still filled with errors either way

I think one of the reasons modern compounds can do as well as they do is because of the small diameter of the carbon arrows, not really all that speed. Less friction, better penetration.

[Marc St Louis]

There's more to good hunting arrows than just momentum or high speed.  You need  broadheads with an edge that won't roll over as soon as they hit something

[El Destructo]

Kegan....Here is something to Chaw on....when I was Hunting and Shooting the 3-D Circuit here in Texas...New Mexico and Oklahoma....I shot nothing but Carbon Express CXL 350's ...these Arrows are twice the size of a Standard Carbon Arrow...9.3mm....but Weigh only 8.3 grains per inch of Shaft....so a 30 inch Arrow...249gr...plus Nock...10gr....plus Insert...28gr...plus point...125gr...was only 412 grains of Total Arrow Weight...pushed out of a 70 pound Bowtech Patriot @ 346fps.....I never had an Arrow stay in an Animal...all total Pass Throughs...with Monster Fat...But Super Light Arrows...If I was going to go bvack to Auto-Cad Designed Super Bows again...I would go back to these Light Arrows too...They are Devastating on Game Animals

[Little John]

I was just reading where Howard Hill shot 700 grain arrows from his 110# longbow. Well under 10 grain per pound.     

[Kegan]

Mike- I don't really see a 400 gr arrow as that light, especially sicne we know a 40# bow is good for deer. Get that thing going super fast and it'd be super-duper lethal (technical term ). I've jsut spoken to a few archers my age who use compounds who lightened their arrows to 200-300 grains just so they could get it going faster... and then some of them put mechanical heads on 'em.

I think I've been phrasing it wrong- I'm in the same boat as Justin and Shannon. I think a minimum weight of 500 gr is a good place to start with a traditional bow, and heavier is more helpful- regardless of the bow's draw weight. I don't think I've ever actually shot a 10 gpp arrow

[recurve shooter]

easier to stop a go-kart going 90mph than a freight train going 5mph. 

same concept applies to arras.

[Steve Cover]

........An simple equation. "would you rather get hit by a pencil going 250 fps or a telephone poll going 150fps ?" Ok to start a new discussion or is it argument....."does speed kill or kinetic energy ?" Personally I would rather take a 243 round than a 50/70. Discussion anyone ? Oops Chris didnt mean to hijack youre thread.

Interesting questions. 

First to address your rifle analogy:
You must consider that the 243 is hypersonic and will disrupt much more tissue with hydrostatic shock than a subsonic 50/70 bullet that just disrupts a 50 Cal. surface. 
The 243 will dump all of its energy in your body, and probably (Depending on bullet construction) not exit.
Considering the thickness of your body, after punching a 1/2" diameter hole through your body, all of the energy the bullet is still carrying will be useless to cause you any harm.

So, trying to compair light/fast arrows with slower/heavier arrows that are still very far below the hydrostatic threshold, makes the issue of tissue damage caused between bullets and arrows an Apples/Oranges compairson.

Now, Pencil/telephone pole comparison.   Would you rather be hit by a little girl on a tricycle peddling as fast as she can, or by an 18 wheeler, going as fast as the little girl can push it?

Again, we have a major difference in mass.   To make a fair comparison both projectiles should be assumed being launched by the same bow. 

So a 50 Gr (0.007+... pounds) pencil shot at 500 fps (340.9 MPH) would carry about 3.57 Pounds Feet of momentum....

Now take your 1000 pound (7,000,000 gr) telephone pole and drive it a velocity to match the pencil's momentum (Shot out of same bow) = 0.00357 feet per second, (.189+ MPH) . Not much punch.
Also, to be fair, shave down the first several feet on the front of the telephone pole to equal the same surface area as the pencils.  Your telephone pole will still only be traveling less than 1/5th mile an hour and very slowly disrupt the same amount of tissue.

The pencil telephone pole analogy reflects too large of a difference in size to easily relate to.

I will concede that a heaver arrow will be better at breaking a shoulder or a hip bone, but will the light faster arrow be sufficient"

I've never had a hunting arrow kill a big game animal by the energy it impacted with.  It is the broadhead that causes a bleed out and death, not a stompin impact....

I've broken ribs on both sides of a couple of white tails shot with a 65 pound recurve and 450 Gr arrows.  The other broadside hits that didn't strike a bone were clear shoot throughs.

Here is a picture of a deer that a friend of mine shot last year.  This is a standard 29" POC shaft.  Penetration through the skull was sufficient.  (Even wasted some energy by over penetration.)



I guess, I just don't understand why arrows above about 450 grains would be wanted for normal hunting.

Anyway, My 2 Cents

Steve
Certified Firearms & Reloading Instructor.

[Kegan]

Steve- good stuff! I think it goes back to what you define light as. Despite the fact that I don't actually shoot 10 gpp, I think of arrow weight in those terms (so a 450 gr arrow would be no less than 45#). Not really too light. But my own arrows are 600 gr. because my bows aren't efficient enough to get a lighter-than-that arrow moving any faster than that. As the forefathers of bowhunting have proven, a heavier arrow carries more momentum for either a less efficient bow or a larger, denser animal (African).

[Steve Cover]

Steve- good stuff! I think it goes back to what you define light as. Despite the fact that I don't actually shoot 10 gpp, I think of arrow weight in those terms (so a 450 gr arrow would be no less than 45#). Not really too light. But my own arrows are 600 gr. because my bows aren't efficient enough to get a lighter-than-that arrow moving any faster than that. As the forefathers of bowhunting have proven, a heavier arrow carries more momentum for either a less efficient bow or a larger, denser animal (African).

Good points Amigo,

I'm NOT condemning the use of heavier arrows.  I'm just trying to get my head around why a 600 Gr. arrow would be desireable over one 3/4th that weight for Deer/Elk sized game.

Washington State requires a minimum of 437 Gr. Arrows for hunting...  By my definition, arrows lighter than that are "Light Weight Arrows". 

It is all a matter of definition.....  A mistake I made when I posted....  ("Define what your talking about first"... I didn't)

I believe the arrow that Howard Hill used to kill an elephant was over 1000 Gr. In weight, shot out of a 120# bow.  (Long ago memory in play here.... Please correct if I'm wrong).

Fred Bear also killed an elephant, as I'm sure other archers have.  There is little doubt that the arrows used were as heavy as possible...

Your, explanation of bow efficiency, is clearing up the subject for me....

Appreciate you're responce..

Steve