Arrow set up

chiefdale

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taking first trip in july to SA for bowhunt .noticed most outfitters recommend 450 grain arrow with a least 60 pound draw .my question which set up is better for shooting thick hide animals(zebra,gemsbok,wildabeast) 1)350 grain arrow with 100 grain broadhead vs 300 grain arrow with 150 grain broadhead. shots 20 to 25 yrds. my current set up 70 pound with arrow shaft 318 grains and a 100 grain broadhead is 282 feet per second.
 
would be curious to know the same..

IF I end up taking a bow to SA in June, I dont have any intent of hunting a larger/thicker hide animal like gemsbok or wildebeest.. Im more interested in smaller/thinner skinned game like blesbok and impala..

But if that perfect shot on a perfect wildebeest presented itself... I might not be able to resist the temptation... :)
 
The arrow with higher foc will get more penetration. Now any of those weight wise at that speed will be pass thru unless heavy bone is hit. I shoot a 370grn arrow for elk out of a 60lb bow at 300fps with no doubt in it. I'll be taking my bow with me in april and as long as you know the animal vitals and have a good sharp head I would worry to much with a 70lb bow.
 
Arrow placement and a quality razor sharp broadhead of good design are more important that high poundage. I shot through kudu, waterbuck, and blue wildebeest with a #60 recurve and 570 grain total arrow weight shooting only about 175 ft per second.
 
Arrow placement and a quality razor sharp broadhead of good design are more important that high poundage. ..............

Exactly.
 
chiefdale,

Devin Twitty and Jeff have hit the key areas of importance when considering your African bow hunting set up..... Front of center weight distribution in your arrow construction is paramount for good penetration. A quality arrow combined with a heavy duty, compact fixed blade broad head placed in the right spot is another major component to success.

As a general rule, most North American hunters already successfully shoot bow & arrow combinations that more or less fall within the parameters that will also perform well on African plainsgame. Therefore, it is not usually necessary for them to go out and buy all new bows, arrows and broad heads for their African bow hunt. Still, a few equipment tweaks are sometimes recommended and necessary to ensure maximum performance, short tracking jobs, and happy hunters.

My advice is the heavier the arrow the better with emphasis on the FOC.... The stronger the broad head the better. Arrow speed is really a minor consideration over the larger benefit of momentum that will be created by forward weight of the arrow. My personal bow is set up at 70lbs., 29" of draw, and an overall arrow weight of 685 grains. I also recently switched to 2-blade, single bevel broad heads for Africa. The arrow hits game like a hammer, resulting in complete pass-thrus every time with proper shot placement.... Two holes are better than one when it comes to bow hunting.

Similarly, on our first safari, my wife was set up at 52lbs, 27 1/2", with a 400 grain arrow at 18% FOC. She got decent penetration with good placement but not nearly efficient enough for our satisfaction. By our second African Safari, we upgraded her to arrows just shy of 640 grains with a 2-blade single bevel broad head, and 30% FOC. Every subsequent game animal taken since has resulted in complete pass-thru's with her set up. Sure, the arrow is slower, but she is selective in her shots and she kills what she hits. We are now devout believers in the religion of momentum at the church of FOC. There is no such thing as too much penetration..
 
Im a total newbie when it comes to archery.. so please forgive my ignorance...

how are you guys coming up with your arrow weight calculations? Or am I maybe missing something (there are perhaps heavier shafts, or something you guys are doing to make your arrows heavier that Im not aware of?)

I'm currently shooting carbon express whitetail arrows, 250 spine, 30". They are 7.04 gr per inch.. so 211.2gr.. Ive got carbon express inserts (11gr), launchpad nocks (9.9gr) and Im using 100gr muzzy broadheads..

If Im doing this right, Im shooting 332.1gr arrows..

I know I could pick up another 25gr by going to a 125 gr broadhead.. and I could pick up another 30gr by going with most 350 spine shafts.. but even doing that I'd still only be shooting 387.1gr...

Where are you guys getting all of the additional weight?

(Or am I doing the math wrong somehow? Or leaving something out of the equation?)
 
Arrow placement and a quality razor sharp broadhead of good design are more important that high poundage. I shot through kudu, waterbuck, and blue wildebeest with a #60 recurve and 570 grain total arrow weight shooting only about 175 ft per second.
Exactly right.
 
Remember, when the "gurus' worked out what poundage and arrow weight you need to kill an animal they still used a sundial to estimate the time. Things have change technology wise wrt to bows, arrows and broadheads. If you read the latest bow magazines you will see there is a bigger animals that is now taken with equipment far below the "recommended" requirements. This is possible because shooters and equipment gets better ensuring a clean kill.

I hope this info will help you understanding a little better.

Use the information at you own discretion. This info was drawn up on basis that all things are equal.

Although kinetic energy and momentum are traditionally used as indicators in the hunting community, it has severe shortcomings when applied to low energy weapons as discussed above, and is being replaced by something called momentum density

This equation, SABA applied to archery, not with the purpose to calculate penetration, but for investigating the relationship between speed and weight and its correlation to penetration. The result of investigating penetration into bone tissue, showed a relationship between weight, speed and penetration (Fast Arrow) that exactly mirrored weight x speed squared, or kinetic energy. Penetration into soft tissue was totally different and there the relationship closely resembled momentum: weight x speed to the power (Heavy Arrow) of 1.3, where momentum is of course weight x speed to the power of 1. This clearly demonstrates the reason why different researchers favour different indicators (momentum vs. kinetic energy) as penetration indicators.

NB, The problem with defining penetration ability (PA) recommendations is the great many factors influencing it, and the huge variation of penetration in different tissues by projectiles with marginal abilities. Factors affecting arrow penetration, excluding the tissue type, as found by the studies of for example Dr Ed Ashby to have a high correlation, is momentum, and arrow design. In arrow design are included the number of blades, the angle of the blades, the cutting diameter, surface area, and the diameter of the shaft relative to the hunting point's shaft diameter.

In an effort to quantify all these measurements on the broadhead, Dr Ashby suggests the use of a tissue penetration index (TPI = length/(Blade Count x Cutting diameter/2) ). This index captures most of the listed attributes, but excludes the effect of the general size of the hunting point (see next table). It also fails to provide for modern multi-blade hunting points with so called "bleeder blades."

NB. The chisel tips are very strong, and very robust. There are conical ones, square ones, triangles, and some have the flat areas of the tip machined out. The main advantage of these tips is their strength. You can break bones with them, and they will still have cutting edges to penetrate flesh thereafter.

NB. The cut-on-contact (COC) types are less durable, and may fail on hitting bone. However, their penetration in hide and flesh is by far superior to the chisel nose broadheads.

NB.You must remember that all animals are very heterogeneous, and consists of very hard bones, very tough sinews, muscles that move across the arrow's path, and right at the other end of the scale, tissue that is largely just airbags (lungs and genuine airbags in birds). The ability of an arrow to penetrate these is dependent on the arrow's mass and its speed. The importance of mass vs. speed changes as the hardness of the material changes. For some materials kinetic energy, where speed is much more important than mass, will be indicative. For other materials, speed plays a relatively small role in relation to mass.

NB. In an effort by SABA to define a more comprehensive index, a new formula is suggested. Herein the following assumptions are made about the hunting point:
1. The larger the point size (cutting diameter), the more difficult it will penetrate.
2. The larger the angle of the blades with the shaft, the more difficult it will penetrate (reaching a maximum at 90°),
3. The more blades it has, the more difficult it will penetrate.

As you can see, slower and lighter arrows lose more speed breaking ribs than faster and heaver ones.

Approximation of energy needed to break a rib per animal mass:

Animal weight kg / energy needed
10--------------------- 12
50--------------------- 19
220------------------- 29
1060------------------ 45
5000------------------ 70


Warning: Although tests like these try to prove heavier arrows have more penetration, they rather reflect that the bow is slightly more efficient at higher arrow weights. The medium is not comparable to wet tissue, but is indicative of penetration into bone.

This model works well over a range of arrow weights, but also has its limits. The virtual model predicts that as you increase the arrow weight; the arrow's kinetic energy will always increase, reaching a limit close to the total draw energy. This is a better fit for traditional bows and recurves, but with compounds there is a definite optimum arrow weight, beyond which its kinetic energy decreases as arrow weight increases. A better energy model for compound bows looks like this:

Draw energy = (arrow weight + virtual mass + K (arrow weight)3 ) x arrow speed2 / 450240.
 
Mdwest,
Your calculation is accurate less the additional 15-25 grains that would account for a shaft wrap and fletching weight. Still, at 7 gr per inch, you are shooting a very light shaft for a hunting arrow. Most hunting arrow shafts will be 9 gr per inch and up.

There are several arrow manufactures that offer arrows specifically designed with FOC (forward weight) already built into the shaft. To increase total arrow weight as well as FOC, you can do several easy things including simply screwing on a heavier broad head or a weighted screw-in insert adaptor. You can also use heavier brass inserts that can be custom cut to any specific weight. This option would likely only be used to built arrows for really big game where bone splitting penetration wiould be a consideration.

As far as determining your FOC, there is a simple calculation used to determine that based on total arrow length and the measurement to the arrow's balance point.... Now keep in mind, when you experiment with changes to arrow weight and FOC, you will be affecting the arrow flight relative to spine deflection. In other words, you cannot just add lots of tip weight to your current arrow and expect it to fly perfectly without at least some tuning adjustments. I realize all of this sounds like it can get pretty technical, and it can.... However, for most hunters pursuing African plainsgame, you can find the right set-up with just a few minor tweaks and gear modifications.

In your case, I hate to convince people to spend money, but I would recommend buying some arrows with a higher gr per inch than 7.... Start out with just a half dozen from a manufacturer that has the FOC built into the shaft in the 9-12 gr per inch range. Then add a 25 gr weight increasing adaptor or bump up to a 125-175 grain broad head. You can purchase a field point test pack of various weights to experiment with before committing to buying broad heads. At 30", that should get you to at least a 500 grain total weight arrow with more than enough FOC for excellent penetration.

BJX13,

You have provided some excellent technical information..... The speed/momentum/kinetic debate is on every bow hunting forum out there, and there is a lot of outdated and inaccurate information that is still being argued as you mentioned...... Controversy aside, I base my equipment selections on results that I can see with my own two eyes. You don't get complete pass thrus with bow energy calculators.... You get them by the application of physics, common sense, and practical experimentation much in the same manner as Ashby conducted his field tests. One can argue the physics of it all day long, but the results are fairly indisputable.
 
I shoot gold tip arrows and use the fact weight system they have. You could set up arrow with lots of weight upfront and still use the common 100grn heads this way. I've put 50grns up front on my arrows using the weights. As said 7grn per inch is light. I'm very sure the arrow would do its job as long and no heavy bone is hit and there is a good sharp head at the tip. If your worried about penetration you could step up to a .204 dia arrow to help a little more but my .246 gold tips will blow through a block target for 20 yards with my broad heads.
 
............... practical experimentation much in the same manner as Ashby conducted his field tests. One can argue the physics of it all day long, but the results are fairly indisputable.

That's the truth.
 
Mdwest,
Your calculation is accurate less the additional 15-25 grains that would account for a shaft wrap and fletching weight. Still, at 7 gr per inch, you are shooting a very light shaft for a hunting arrow. Most hunting arrow shafts will be 9 gr per inch and up.

There are several arrow manufactures that offer arrows specifically designed with FOC (forward weight) already built into the shaft. To increase total arrow weight as well as FOC, you can do several easy things including simply screwing on a heavier broad head or a weighted screw-in insert adaptor. You can also use heavier brass inserts that can be custom cut to any specific weight. This option would likely only be used to built arrows for really big game where bone splitting penetration wiould be a consideration.

As far as determining your FOC, there is a simple calculation used to determine that based on total arrow length and the measurement to the arrow's balance point.... Now keep in mind, when you experiment with changes to arrow weight and FOC, you will be affecting the arrow flight relative to spine deflection. In other words, you cannot just add lots of tip weight to your current arrow and expect it to fly perfectly without at least some tuning adjustments. I realize all of this sounds like it can get pretty technical, and it can.... However, for most hunters pursuing African plainsgame, you can find the right set-up with just a few minor tweaks and gear modifications.

In your case, I hate to convince people to spend money, but I would recommend buying some arrows with a higher gr per inch than 7.... Start out with just a half dozen from a manufacturer that has the FOC built into the shaft in the 9-12 gr per inch range. Then add a 25 gr weight increasing adaptor or bump up to a 125-175 grain broad head. You can purchase a field point test pack of various weights to experiment with before committing to buying broad heads. At 30", that should get you to at least a 500 grain total weight arrow with more than enough FOC for excellent penetration.

BJX13,

You have provided some excellent technical information..... The speed/momentum/kinetic debate is on every bow hunting forum out there, and there is a lot of outdated and inaccurate information that is still being argued as you mentioned...... Controversy aside, I base my equipment selections on results that I can see with my own two eyes. You don't get complete pass thrus with bow energy calculators.... You get them by the application of physics, common sense, and practical experimentation much in the same manner as Ashby conducted his field tests. One can argue the physics of it all day long, but the results are fairly indisputable.


Great info in there. Thanks!

I may give the carbon express mayhem hunter (9.8gr per inch) or maxima hunter (8.9gr per inch) a try, and look at some 125 gr fixed broadheads based on the above.. that should bring me up to somewhere in the 460gr range..

Im only shooting at 60 pounds right now.. but I would think 460 @ 60lbs should be enough for an ethical kill on deer/hog sized game.. (all Im really planning on trying to hunt in 2017 with a bow.. although if I can get my skills up to at least "decent", I may take it with me to SA in June and try for some smaller plains game)..

Ill keep the CE Whitetails with 100gr field tips for practice arrows (knowing their POI will be very different from whatever I brew up next..).. and not plan on taking them to the woods..
 
460 grains, 60 lbs with a sharp head will take any PG animal with a good shot.
 
I'm currently trying to adjust my arrow setup as well and is what I have found out so far is that a heavier arrow setup is the way to go as well as a good tough broadhead (two blades) that have less surface area contact.
I'm about to switch from my BE Spartans 350 spine at 8gr per inch to an arrow of 300 spine at 9gr per inch with a 40gr insert and a 125 gr 2 bladed broadhead for a total weight of 499gr(including nocks, etc) from my 440gr setup for whitetail.
Good luck and let us know how it works out

PS I'm also trying to get a heavier setup with an increase in FOC from 11% to hopefully at least 20% due to how tough I've heard that wildebeest and Zebra can be
 
460 grains, 60 lbs with a sharp head will take any PG animal with a good shot.

I have some video that shows that not to be the case all the time. I would say most of the time yes but if you hit a rib just the wrong way, it might be an issue. When I get homenrxt week, I will post my wildebeest video.
 
I cut a rib in half on a eland bull on entry and exit with 60 pounds and a 450 grain arrow and a coc broadhead
 
And my fixed 3 blade didn't on two zebra shots and a wildebeest. They will pass through at that weight combo and break bones, but not every time. I suspect with a 2-blade head, I might well have but with a three blade on PG, it isn't a guarantee.
 
. I would say most of the time yes but if you hit a rib just the wrong way, it might be an issue.

Agree. Thats why a broadside or quatering away shot is so important. Know of some hunters that tried frontal or quatering towards shots that the arrows did not penetrate because the ribs deflected the arrow
 
Yes, but I never took a quartering towards shot. They were either broadside or slightly quartering away. The arrows I had could do it but it but not on every shot. Maybe I could have learned more with more time in the skinning she'd, but that takes away from hunting time, right?
 

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