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Glenn
22-05-07, 10:28 PM
Here is a good article by Jack Howard on heavy or light hunting arrows. Jack was a very well known bowhunter in the USA and he also made some of the best hunting recurves of the modern era, the GAME MASTER and the GAME MASTER JET...


Heavy Arrows vs. Light Arrows
By Jack Howard
As far back as I can remember there has always been a controversy on which would penetrate further, a slower heavy moving arrow or a fast light moving arrow. Way back in those days I never really had a strong opinion either one way or the other, I did though favor an arrow on the light side for other reasons. I have always been a long distance shooter, and only with a light arrow can you reach out with a good degree of accuracy. My practice sessions have always been a 75 or 80 yards. My reasoning was if I learned to do well here I would even do better for any close shots that might come along. This has worked out well for me as most of my kills have been in the range of 50 to 60 yards, with a few Deer, Elk and Antelope kills ranging from 75 to 85 yards. I have always tested everything I possibly could because without some type of actual test you never have any real true answers. I had delayed though on penetration testing as I had been perfectly satisfied with my hunting results and have always been pressed for time. Back in 1967 Bow & Arrow Magazine asked me if I would do a penetration test article for their magazine. I said I would, this was a good excuse for me to break from the usual grind and find the answer for my own satisfaction, the age old question about penetration. I find that I have some spare room in this catalog issue and think some of you may be interested in my findings. What follows is a condensed version of my 1967 article.
All bow hunters know how important penetration is, yet I have seen and heard of cases where there has been no penetration at all. There are cases where the arrow has hit squarely in the rib cage and bounced back. Still other instances where penetration was only as deep as the broadhead point. Even though these are rare happenings, for the sake of our bow hunting sport, it is best they do not happen at all. There is an assortment of reasons why such things can occur. A few hunters in their excitement forget to come to a full draw, thus losing considerable speed and power. Or a combination of shortened draw and a poorly designed or rounded over broadhead point. Broadheads such as a reverse barb (sawtooth) can cut penetration in half in soft tissue and stop the arrow abruptly if gristle is hit. It's not possible for all bow hunters to have the same efficiency in their equipment, but it is important that each of us try to obtain as much penetration as possible. Some of the things that influence the ability to penetrate are bow weight, arrow weight, broad head point design, arrow speed, draw length. A hunter shooting a bow weight, arrow combination that is 60# at 31" will have considerably more power than a hunter shooting a combination that is 60# at 28". When a bow hunter invests large sums into his equipment and costly hunting trips, it is wise to choose equipment carefully so the hunt will be a gratifying success. Because there are certain arrow-bow weight combinations that are more efficient than others if the wrong choice is made, in certain cases a slight gain in bow weight could cause a loss in penetration.
In setting up for a penetration test, the material used that is to be shot into must be as consistent as possible. For this type of test there is nothing I know of that is more consistent than compressed cardboard. I can shoot 6 matched arrows into cardboard and they will penetrate to exactly the same depth. I made up a strong wood frame to hold and compress the cardboard. What would be the best kind of point to use was the next question. Broadhead points were out, not only would they be difficult to work with, but there would be too many misleading results. Things such as alignment, sharpness, size and type of hole opened, etc. would give a varied effect on penetration. You would only use broad head points for a test if you were testing the penetrating ability of one type of broadhead over another. My test though was not a test on broad head points. I was only concerned on how shaft weight effects penetration, an answer to which could best overcome the binding effect of the carboard against the shaft. Would a shaft on the light side which travels faster, or a shaft on the heavy side at a slower speed have the most penetration. To make this test as accurate as possible, all points had to be exactly the same shape and diameter and remain the same throughout the test. I chose standard steel target points as they are absolutely consistent. Shaft diameters, arrow length, fletching, all had to be exactly the same, identical in every respect except for what I was testing, weight. As I had no method of making up such arrows, Easton Aluminum made these especially for my test. The arrow weights made were 325 grains for the lightest arrow, 480 grains for the middle weight and 650 grains in the heavy arrow which is just twice the weight of the lightest one.
The bow weights used in my test were 40, 50 and 60 Ibs. Out of a bow of a given weight, I think we all realize that as arrow weight is increased, the speed of the arrow decreases. Also as arrow weight is lessened, then the speed of the arrow increases. How though does all this effect arrow penetration, this was the whole point of my test. As for the figures on how the test came out, I won't give all of the many figures as this would only be confusing. With each bow weight shot, the lightest arrow penetrated the deepest, the mid weight arrow had the second most penetration and the heavy arrow had the least penetration. For a comparison with just the light arrow and the heavy arrow. From the 40# bow, the light arrow penetrated 3 ½” further than the heavy arrow. From the 50# bow, the light arrow penetrated 4" further than the heavy arrow. From the 60# bow, the light arrow penetrated 5 ¼” further than the heavy arrow. The penetration range of the mid weight arrow was half way between the light and heavy arrow. In the actual depth of penetration, there are some figures that may surprise a few, in the heavy vs. light division. Just comparing what the light bow with the light arrow versus the heavy bow with the heavy arrow penetrated is somewhat astounding. From the 40# bow, the average depth of penetration of the light 325 grain arrow was 12". From the 60# bow the average depth the heavy arrow penetrated was 11 ½”. If you take a close look at these figures you will note the light bow and arrow penetrated on the average of 1 ½”" further than the heavy arrow with a bow that was 20 lbs heavier. Of course none of us can use a 325 grain arrow for hunting, but I feel the figures still tell us something. For one thing, speed is an important factor that should definitely be considered. Also if you choose the proper arrow-bow combination for your bow, you won't go wrong. In my opinion it is best not to make a decided effort to go real heavy on arrow weight as a few hunters do.
Many have been mislead by a few manufacturers advertisements, especially when they talk about heavy arrows and heavy broad heads giving shock type knock over power. There is no such thing as knock down power when it comes to killing game with a bow and arrow. Knock down power means shock from being hit by a projectile, this does not happen with an arrow. On rare occasions one might catch an animal off balance, but this has nothing to do with shock or knock down power. The fact that the broad head is sharp and pointed in itself takes what little striking shock that might be generated out of the arrow. If striking shock was the name of the game, we would be using blunt points. In conclusion I would like to mention that I made this penetration test because of a request from Bow & Arrow Magazine, plus my own information. I have given the results here as I feel some may be interested. I have no ax to grind on this subject and will be pleased to make a customers arrows any weight he wishes them to be.

perry
22-05-07, 11:02 PM
Glenn , Jack Howards article is certainly interesting cant say I agree with cardbaord and target points as the ideal way to settle this ages old argument but I see whis point . I was keen to note the ranges that he shot his game at , bloody hell wish I could shoot that good , its certainly a different ethic today . The Thompson Brothers Pope and Young , Hill , Fred Bear etc all seemed to shoot at longer ranges than most bowhunters admit today, different era and social attitudes I guess . Still the heavy vs light arrow argument continues, minimun 10 grains per pound for me even for targets , . I note that Hill and Bear prefered heavy shafts for there african trips and used lighter shafts for there north american game , like Jack Howard said match your arrow to your game . regards Perry

Glenn
23-05-07, 11:41 AM
I don't necessarly agree with all of Jacks findings ether Perry but I thought it was worth a look at. At one stage I was using light arrows out of a light poundage recurve and had good success with penetration on pigs but I was using shafts that were a lesser diameter than the ferrule of the broadhead. I didn't have any problems with penetration on pigs but I did have problems with penetration with heavier bows when I was using 3/8 shafts. I always suspected the larger diameter shaft reduced penetration considerably....Glenn... [/quote]

Clinglish
23-05-07, 09:48 PM
I would rather go by the results of Dr Ashby simply because the tests are on flesh and bone ,and with modern equiptment the carbon arrows with good FOC is my choice.

Paul R
24-05-07, 12:17 AM
It is a very interesting artical Glenn, it sure got me thinking.

The problem with those sorts of tests is that there are always so many variables that aren't covered properly.

For example:
- Not having a consistant draw length and release across all test bows.
Draw lengths can be significantly shortened on heavier bows and releases can be less crisp. Both of these can lead to a drastic reduction of speed.

- The efficiency of the test bows in question. Some lighter bows can be far more efficient than heavier bows of the same design, not to mention different designs. By that I mean just because a particular bowyers design is very efficient and shoots an arrow fast at say 45 pounds draw weight, it does not mean that the design will perform as efficiently between 60 and 70 pounds draw weight. The string material used and the silences would have to be exactly the same as well.

- Poor arrow flight. Are all of the arrows perfectly tuned to their respective test bows? It would be extreemly difficult to get all of the arrows being used, flying exactly the same way, that is with the exact same occilations from their respective bows. If all of the test arrows do not hit the target in exactly the same way, from all of the bows, then this would lead to differences in penetration as well.

- Then there is the target material and how it reacts to different arrow speeds, weights and point shapes, as compared to the way flesh and bone would react to a broadhead.

There would be a lot of variables to cover if the testing was to be done properly. It would be an interesting project though. :D

Glenn
24-05-07, 06:29 AM
I know what you are sayng about the different design bows Paul. Some bows are more are more efficent than others, not all bows are equal, in desing and peforance. The FOC of an arrow can make a huge differance to how much penetration you get on game.
One of the biggest problems with penetration I have seen over the years and I have had the same problem myself is being over bowed, when you do not come to full draw because the bow you are using is too heavy for you under hunting conditions you loose a lot of penetration by not coming to your correct draw length. There has been far too much importance placed on bow poundage over the years, it is highly over rated, correctly matched equipment and also matched to the hunter is a lot more important, it's amazing how much money people will throw at a bow and use mismatched rubbish arrows for hunting. At the end of the day it's the arrows that do the killing so the arrows need the most amount of attention...Glenn...

Paul R
24-05-07, 02:25 PM
I agree Glenn, the arrow is the most important part of the equation.

Every time the issue of penetration comes up Glenn, I think of that 42# Defiant of yours shooting perfectly matched, heavy arrows with a high FOC and the complete pass through that you achieved on that big boar. All with your 27" draw length.
It's a brilliant example of why hunters need to worry less about the poundage they pull and more about the actual draw length they're achieving under hunting conditions, the efficiency of the bow they're using and the arrows they're shooting and how well they fly.

As you said, an efficient bow, matched to the hunter and shooting perfectly tuned arrows is definately the key to good penetration. In my opinion heavy arrows with a high FOC and a small diameter shaft (one that is smaller than the broadhead ferrule as you mentioned) also play an important role in achieving good penetration.

I'm looking forward to putting it all into practice again in a few weeks time, maybe on a big toothy tusker or two. :D

pete w
10-06-07, 11:41 PM
I don't buy it.
Give me a heavy arrow{600 to 700GR} with small diameter{carbon} and very high FOC.{20 to 25%}

Asby has also found that light arrows do not penetrate as well as small diameter ,Extreme FOC, heavy arrows on his Buffalo tests.

As for shooting these long distances, it is like the guy betting on horse races, we only hear about the success, never the losses. Archery is about getting close not Rifle hunting with a bow.

Pete

Kimall
10-08-07, 09:21 PM
Ok to bring up an old thread I have a question for all you heavey arrow guys.
If you shoot an arrow weighting 500 grains from a 50 pound bow (10 grains per pound) and you all rekon this is bliss then this weight arrow shot from a 60 pound bow going by your theory is no good as the grain per pound is not 10 any more but common sence says its the same weight arrow going faster so how can it not penertrate better if spine is still right?
Cheers KIM

rory
10-08-07, 09:34 PM
Good call Kim, I've thought the same thing, especially comparing my compound arrows to trad arrows...

I shoot nigh on 600 grain arrows from all my 65-70# recurve limbs, including a 220 grain head. This weight flies well from the curve, but more importantly to me a heavyish arrow gives a nice quiet shot :)

ed
11-08-07, 10:12 AM
I do shoot heavy arrows - around 750 grains from a 67# bow so well over the 10 grain per pound. They fly well and I am happy with them. Now when I can find a hardwood shaft that is lighter for the spine and draw length then I will think about using them. I think all this light arrow stuff is partially a product of new arrow materials. Once you start getting to heavy bows then it is hard to find a light wooden arrow that can handle it.

Piggy
11-08-07, 10:23 AM
I shoot a 650 grain arrow from my 59# recurve.
Black widow have a minimum weight of 8 grains per pound of draw weight to maintain a warranty which is 472 grains for my set up.
I find the heavier arrow flies better and quieter.
At the end of the day though you can the heaviest arrow or the lightest arrow but shot placement is the most important detail.

Having said that with the heavier arrow I believe if your shot encounters bone you will get better penetration.

Glenn
11-08-07, 06:59 PM
Me personally I like the heavier arrows with a high FOC and I also barrel taper the shafts so that the arrow diameter is narrower than the ferrule of the broahead which helps with penetration as well...Glenn...

shane
17-12-07, 06:46 PM
See Slike this....

A circle - for every doubling in diameter - the cross sectional area goes up by 4X as well.

The surface area of the shaft also goes up by 4X

For a THIN light arrow vs a THICK heavy arrow....

The tests and the resultant theory, "appear" to be flawed, because there are NO very closely set INITIAL velocity - as acceleration = force X time...

To be proportional - in terms of penetration, both the light arrow and the heavy arrow MUST be launched as more or less equal speeds - so the light arrow gets launched from the LOWER powered bow, and the heavy arrow gets launched from the HIGHER powered bow.

The cross sectional area, and length of the cylinder, and the relative kinetic energy and the velocity are easily tabulated... (pencil - paper and ratios)

The tests in the article appear to be little more than twang and poke (with a ruler) sorts of science.



To get the very BEST penetration - for a PRACTICAL working archery system - three factors must met.

The arrow (and it's tip) MUST be as narrow as structurally and functionally possible (small cross sectional area), the arrow must be of the highest reasonable density for it's cross sectional area (lead filled core? - or very long?), and it must be launched at the highest reasonable velocity.

Glenn
17-12-07, 09:52 PM
The argument about kenitics versus momentum has gone on for years. I tink that monentum of an arrow is a much better figure to find out how much penetration an arrow will have...Glenn...

perry
29-12-07, 03:07 PM
Crikey you ask hard questions of dumb trad shooters Kim . Do the maths [ no claim to being clever but formula for is momentum mass X velocity ]

500 grain arrow from a 60 # bow at 175 fps = 87500 650 grain arrow from same bow at 140 fps = 91 000

Ed has identified a few factors in arrow penatration 13 of them are
stuctural integrity
arrow flight
extreme FOC
mechanical advantage of broadhead
shaft diameter
arrow mass
edge finish
shaft profile
broadhead arrow siloutte
type of beval edge
tip design
arrow mass above the heavybone threshold
arrow forse derived from bow

For the full guff google Eds penatration study updates particulaly his 07 updates - really interesting -look em up .

My head hurts , just know once I started shootin over 650 grains and worked out a lot of the above all of a sudden [ over 7 or 8 years ] I was shooting more accuratly at 3D targets . When hunting game was downed faster because of more exit wounds / pass throughs . regards Perry

Kimall
29-12-07, 03:19 PM
Well Perry I can be a bit of a trouble maker.:)
The formular you put up is oppisit to the senario I spoke of I said keep the same arrow and up the bow weight not the other way around.For the record I dont disagree with heavey arrows being good it was just another way to look at it.LOL
Cheers KIM

perry
29-12-07, 08:12 PM
I did say dumb trad bow shooters Kim .

When people talk about 10 grains per pound as a fair minimum for traditional arrow weights for whatever drawweight they are using a very broad premis .Firstly trad bows usually like a heavier arrow in terms of efficency and 10 grains per pound is a ball park figure many believe you should start at . All my bows shoot sweeter in the hand with 10 grains per pound rather than 8 grains per pound for example .

Secondly many reason that bows of 40 # shooting 400 grain arrows should get similar performance as in velocity and trajectory that a 50 # bow and 500 grains assuming same design is acheiving .

It comes back to the momentum and the lighter bow cant match the heavier bow so in your example Kim your spot on - it cant match the penatration of the heavier bow unless the archer steps up considerably in arrow mass assuming proper arrow dynamics .

Add some misleading information feed to us by the marketing guru's ,plus plain ignorance , publish in a few magazines mix with a bit of time and we get Dogma - any wonder people are confused or trouble makers. regards Perry