FAQ — Ashby Bowhunting Foundation

Frequently Asked Questions

Important Terms Used in FAQ

NBEF: National Bowhunter Education Foundation

IBEF: International Bowhunter Education Foundation

CP: Center of Pressure

TAW: Total Arrow Weight

FOC: Forward of Center

EFOC: Extreme Forward of Center

A&A: Adcock and Ashby fletching profile (1/2" high with 90-degree back edge and straight-taper to the front, regardless of length: basically a wedge shape.)

Q. who is dr. ed ashby?

A. Dr. Ed Ashby invested 27 years in the study of arrow performance and broadhead lethality. Starting in 1981, while working as a PH in Zimbabwe, Dr. Ashby was recruited by the Mkuzi Game Reserve head Game Ranger Tony Tomkinson to assist in a bowhunting research study. At the time bowhunting was not legal in South Africa. The government commissioned a study to determine if African game could be ethically and humanely harvested with the bow and arrow.

Four years later, Dr. Ashby and his team published what has come to be known as the “Natal Study.” The research was based not on the scientific method but outcome driven experimentation. Arrow penetration tests were conducted on hundreds of freshly culled animals and results were meticulously recorded and documented.

In 1986, based on Dr. Ashby’s Natal Study, the South African government legalized bowhunting. Legalization in South Africa acted as the catalyst to open bowhunting in many other Sub-Saharan countries. The Natal Study was the definitive document used to successfully lobby for bowhunting legalization.

Upon completion of the Natal Study, Dr. Ashby continued his arrow and broadhead penetration research for another three decades. His research has led to empirical findings in arrow lethality, revealing the 650 grain heavy bone threshold, the 19% FOC threshold, and the effectiveness of single bevel broadheads on breaking bone as well as increasing soft tissue damage.

Q. Why does the Ashby Bowhunting Foundation Exist?

The Ashby Bowhunting Foundation’s goal is to provide the bowhunter with the information to achieve highest possible success rate and reduce the wound/non-recovery rate of big game to the lowest level possible. Through a program of continuing research, the Foundation seeks to find the most lethal arrow setups, considering all possible hits under real hunting conditions, and to make the results of this testing available to the global bowhunting community free of any cost, utilizing multi-media outlets for information and test results. More information.

Q. Can you help me build the fastest shooting bow?

A. No. We are about arrow lethality on whatever animal you hunt. Penetration requires arrows with enough structural integrity to stay intact and carry enough momentum to penetrate through an animal. If you have to use the lightest and fastest set up, please use an efficient cut-on-contact, razor sharp head to aid arrow penetration. The animal you are hunting deserves an ethical hunter.

Q. What is FOC, Forward of Center?

What does weight forward of center mean? The common answer is: FOC represents how far forward the arrow’s balance point is from the shaft’s midpoint … or the mid-point of the arrow’s total length; and we will discuss that “definition difference” later. FOC is specified as a ratio of balance point to shaft’s (or arrow’s) mid-point; in percentage. For practical purposes; uses archers commonly apply FOC to; the definition(s) above is sufficiently correct. However, should one wish to be precise: FOC represents the percent a projectile’s gravitational balance point is forward of the projectile’s center of pressure (CP). The CP is that point where the maximum “bending force” is exerted upon the projectile. The CP is dynamic for an object in flight; changing as propulsion forces, resistance forces and forces exerted by moving air currents change. For convenience, our “practical purpose” formula(s) merely assumes the CP to be at the mid-point. More information.

Q. DOES USING A HEAVY ARROW AFFECT YOUR TRAJECTORY?

A. All arrows have trajectory depending on their weight and how efficient a bow from which they are they are shot. Trajectory is up to the individual bowhunter to determine what they can shoot accurately. An arrow with more mass will carry a more consistent velocity downrange than an arrow with less mass, so compound shooters using multi-pin sights will notice more consistent pin gaps. While the lighter arrow might have slightly tighter pin gaps at closer distances, with the loss in velocity at longer distances those gaps widen.

Q. Why is a heavier, higher foc arrow and broadhead System more lethal?

A. An arrow with more mass carries more momentum and inertia. Heavier arrows with at least 20% FOC and sharp single bevel, cut on contact broadheads, aid in efficiency for penetration and with enough overall TAW (Total Arrow Weight) will substantially increase the likelihood of a complete pass through, resulting in a more certain, quicker death. Many times the animal will fall within sight of the hunter.

Q. Why is arrow FOC such an important Penetration Factor?

Testing on freshly downed real animals indicates that, while maintaining the arrow’s overall dimensions, increasing an arrow’s FOC shows a substantial nonlinear relationship between the FOC and increased arrow penetration. These increases are first manifest when arrow FOC reaches 19% FOC and the percentage of penetration gain becomes ever greater with each incremental increase in FOC.

In simple terms, this means the percent increase in penetration measured when FOC is increased from 20% to 21% is greater than that shown when FOC was increased from 19% to 20%, and so on. For each increase in the arrow’s FOC both the percentage and actual amount of penetration gain increases at an ever-faster rate. This is a type of Exponential Growth. Think of this in terms of a savings account where you are paid a higher interest rate each and every month on both principal and all previous earned interest. The amount of money in your account increases at an Exponential Rate.

The graph shows the approximate average penetration gain as arrow FOC was increased. As you can see, somewhere around 29.5% FOC the average penetration has tripled, from 10 inches to 30 inches. Remember that this was real-world testing on freshly-downed real animals – mud, hair, hide, muscle, connective tissue, heavy bone and internal organs, backed by the off-side layers.

BUFFALO TESTING

Here’s a real hunting example of FOC’s effect on arrow penetration, and is for one of the many arrow setups used in the testing. At 31.4% the 655 grain, eleven-factor arrow (it had a light-weight parallel shaft) achieved a near-passthrough on a hunted mature Asian Buffalo bull, hanging up on the buffalo’s off-side shoulder by the tiny A&A fletching. This shot was from approximately 20 yards on a trotting buffalo and was from my 82# longbow – at what most would consider ‘very low velocity’ and which the ‘recommended guidelines’ consider to be ‘inadequate Kinetic Energy’. That’s why FOC is such an important factor.

The important takeaway is: the higher you can get your arrow’s FOC, while maintaining structural integrity and perfect arrow flight, the greater your arrow’s penetration will be. The potential increase in arrow penetration at the upper limits of arrow FOC is enormous.

Q. Do tapered shafts really make a difference?

A. In short - yes. With normal to high FOC arrows, and possibly extreme FOC arrows too, shaft profile affects penetration. In fresh tissues, tapered shafts out-penetrate parallel and barrel-tapered shafts of the same mass, force, material and shaft finish, by 8 to 15 percent. Whether this penetration gain is an effect of the substantial FOC increase, or other factors, is unclear. With like materials, tapered shafts have a higher FOC. The taper may act as a reverse inclined plane, constantly lowering the rate of increase in shaft drag the deeper it penetrates. The progressively increasing cavity created between shaft and tissues may facilitate the flow of shaft-lubricating blood, reducing friction.

Q. why single bevel heads?

A. The advantages of single bevel broadheads are many. If you can’t get through the bone, penetration stops. The powerful rotational force of single bevel broadheads results in massive bone splits – especially in long bones. Single bevel broadheads regularly turn what would be a non-penetrating wounding hit - into a killing shot.

Note: Your arrow must be of sufficient weight and strength to drive the broadhead through and withstand the forces involved in breaching the animal and any bone encountered.

Q. Does mechanical advantage mean mechanicals have an advantage?

A. No. Mechanical heads are known to be less efficient, and a reason the NBEF/IBEP teaches not to use them on bows with less than a 50# draw weight. The Ashby Bowhunting Foundation does not recommend using mechanical heads on any animal, but we can point to one head tested in 2022 that held together for those that want to shoot a mechanical.

Q. what are the basic steps for a bowhunter to use this system?

A. The steps include:

Assessing your equipment, poundage, draw length, and range of big game animals hunted.
Purchasing practice arrows matched with your hunting setup
Tuning and practicing efficiently and successfully.
Hunting successfully

Q. What do you recommend for a traditional bowhunter, shooting a 53 pound recurve and hunting elk and deer?

A. We do not recommend manufacturers, but will provide you guidelines to help you build the heaviest arrow that you find trajectory acceptable, while achieving perfect flight. Every bow/shooter is different, so it is up to you to test multiple arrows/weights to determine what works best.

Q. WILL THIS WORK FOR MY CROSSBOW?

A. Yes, following these guidelines will also work on your crossbow. There are a few manufacturers that have equipment to get you reasonable bolt weights for hunting most game animals, but for large thick-skinned game you will likely have to get someone to custom build your equipment. We can make recommendations to you for custom bolts.

Q. What do you recommend for a compound bowhunter, shooting a 70 pound bow and hunting brown bear?

Q. how do I match practice and hunting arrows?

A. Start by focusing on your hunting arrows and then match your practice arrows to your hunting arrows. The number one factor; the single most important arrow feature; is the structural integrity of the arrow system: broadhead; shaft; and all shaft components. To reliably achieve effective, predictable penetration resulting in a lethal hit, the broadhead and the shaft must remain undamaged; regardless of tissues encountered or angle of impact with those tissues. More information.

Q. Does using the Ashby based systems affect your arrow flight?

A. No, perfect flight must and can be achieved. See Factor #2 of the 12 Factors of Arrow Penetration.

Q. What manufacturers make ashby based systems?

A. Tuffhead, Bear, Abowyer, Grizzly, GrizzlyStik, Kudu, and Zwickey are a few that manufacture single bevel broadheads. Others are starting to understand the benefits of single bevel heads and manufacture them.

Q. Will the fixed blades hit the same place as my field points off my compound bow?

A. If your compound bow is tuned the answer is yes. The bow is either tuned, or it is not tuned. Of course, the shooter has a lot to do with it also.

Q. How do i tell what is a left bevel or right bevel?

A. With the broadhead pointing away from you, which side do you see sharpened? If left, it is a left bevel. If right, it is a right bevel. Be sure to match left helical or left offset to left bevel broadheads and right helical or offset to right bevel broadheads, or they will be working against each other.

Q. Do you teach bowhunter education classes?

A. No, we specialize in arrow and broadhead lethality to identify how to cleanly kill whatever you are pursuing with a bow and arrow around the globe. We share this knowledge base with bowhunter ed instructors, bowhunters, wildlife agencies and other organizations interested in helping bowhunters become more lethal through the use of more effective and efficient equipment. We leave the hunter safety classes to the hunter ed instructors, and recommend all bowhunters take the NBEF/IBEP Bowhunter Safety Class, whether or not mandatory to hunt in your area.

Q. Rob, how did you become the president of Ashby Bowhunting Foundation?

A. In 2017, a group of passionate, dedicated, bowhunters came up with the idea to form this foundation. As we progressed and needed to establish our officers, I was honored and humbled to have been asked by the other co-founders and directors to be the President of the Foundation. I look forward to serving the Foundation for the betterment of all bowhunters worldwide.

Q. How can I get involved to support your work?

A. Consider a one time donation or if possible, donate monthly, subscribe to our newsletter to stay up to speed on current and upcoming events.

Q. I shoot a 50# recurve with a draw length of 29 inches. Using this system, how close do I need to be to my quarry before taking an ethical shot?

A. All men are created equal, but they don’t stay equal. This is a shot only the individual bowhunter can determine.

Q. Is there any research available regarding the failure rate of mechanical broadheads?

A. One mechanical tested in 2022 survived the Structural Integrity portion of testing. That is the first mechanical in our testing that did not fail since testing began in the 1980s. Glad to see the improvement.

Q. Why do you use and recommend the A&A fletching for EFOC arrows?

A. Feathers are significantly lighter than plastic fletches, resulting in higher arrow FOC (Forward of Center). The A&A fletching cut is lighter than equal-length parabolic cut feathers. Because EFOC arrows have a longer rear lever (the ‘steering arm’) they require less fletching than normal and high FOC arrows to achieve stable broadhead flight. A&A fletching should be tuned to your arrow setup. You want to use the minimum fletching that will stabilize your hunting arrow under all wind and shooting conditions. Note, the A&A, Adcock and Ashby fletching profile is a half inch high with a ninety degree back edge and straight-taper to the front, regardless of length, basically a wedge shape. More information is available about tuning A&A fletching for EFOC arrows.

Q. Most sources say shot placement is the most important thing in arrow lethality. Shouldn’t it be listed as the number one factor? Why is it not anywhere among Dr. Ashby’s 12 Factors?

A. One should always try for the best possible shot placement … but when hunting things happen. There are things the hunter can control and there are things beyond the hunter’s control. Never forget that the animal gets a vote too!

It’s rare for an animal to not react to the shot and that reaction, or at least a significant portion of the reaction, occurs before the arrow reaches the animal. That’s when the animal gets to cast its vote! Because the animal gets this vote it’s impossible to predict beforehand where the shot will impact.

The best a hunter can do is maximize the terminal performance potential of the arrow he uses. His arrow must remain structurally intact. If some portion of the arrow system fails on impact or during penetration how perfectly the shot is placed no longer matters and the shot may well result in a nonlethal hit. All the Penetration Factors are things within the hunter’s control which will maximize the likelihood of the hit being lethal, whether the shot is ‘perfectly placed’ or whether it is less than optimal.

Q. Does the Heavy Bone Threshold mean that every arrow weighing 650 grains or more will always break through heavy bones?

A. No! What the testing on real animals indicated was that every broadhead tested showed a marked increase in the frequency with which it managed to penetrate heavy bone whenever the entire arrow system remained structurally intact AND the arrow’s weight was at or very near 650 grains.

With a ‘poor bone-performance broadhead’ its bone-breaching rate may suddenly jump from 8 or 9% to 12 or 15%. In the testing, for all broadheads having a Mechanical Advantage of 2.6 or greater the heavy bone-breaching rate abruptly increased to 100% when arrow weight was at or very near 650 grains AND the arrow system remained structurally secure.

Q. Do I really need a 650-grain arrow to kill deer?

A. No! When everything goes perfect virtually every hunting arrow setup will work. However, everything going perfect on every shot, or even most shots, under hunting conditions is not the norm. Incorporating any of the Penetration Factors into your arrow system increases the lethality potential on all shots. Think of it as an insurance policy. The more of the Penetration Enhancing Factors you incorporate into your arrow system the better your insurance policy is.

Q. I’m new to bowhunting and will be using a crossbow. Can you help me with information about what arrows I should use with my crossbow?

A. The terminal performance of crossbow arrows or bolts is dictated by all of the same Performance Enhancing Factors as arrows fired from vertical bows. Once the arrow is in flight it does not matter what it was launched from. For detailed information specific to crossbows ABF highly recommends Jim Aken’s book, It’s All About the Arrows! Engineering Arrows for Enhanced Hunting Performance.

You can get your book directly from Jim by emailing him at jim_aken@hotmail.com. Autographed copies are available.

Q. Where can I get a copy of Dr. Ashby’s book?

A. Dr. Ed Ashby’s book: Now, ...: Ramblings fron the Old Derelict Bowhunter is available on Amazon.Your purchase helps support wounded members of our Armed Forces. 100% of the author’s profits from sales of “Now…” go to Fisher House Foundation, a charitable organization that provides assistance to the families of severely wounded warriors, so that the family members can be with their loved ones during their period of recovery. Additional donations can be made through the Fisher House Foundation.

Q. Dr. Ashby, what are your thoughts on building different arrow setups for specific hunting situations?

A. Though my hunting arrow setup constantly evolved as more was learned, at any given time I used only one arrow setup for all of my serious hunting and all my practicing. I used that one arrow setup for everything from small game up through Cape/Asian buffalo. The only changes I made to this arrow setup were changing to blunts for some small game, wide-cut broadheads for turkey hunting, and adding different fletching when hunting aerial game, such as geese and sandhill cranes.

Obviously, any arrow setup capable of cleanly and rapidly dispatching a Cape buffalo will do the same on all lesser game. There’s also the undeniable fact that shooting the same arrow setup for everything, all the time, develops a familiarity with how that arrow flies, at all ranges. That applies to both compounds and traditional bows, as well as crossbows.

Q. Dr. Ashby, having hunted with all types of bows, why do you prefer to hunt with a longbow?

A. When guiding clients who were hunting with compounds this was probably the most common question I was asked, and my reply, “Because it’s faster than your bow”, always brought an astonished look and a rapid challenge to my reply. In response to this challenge, I always suggested the following small test. We both stand side by side, 20 yards from the target with bow in hand and an arrow on the string. At the ‘go’ signal we both draw and place an arrow into the ‘kill zone’ as quickly as we can. I was never beaten by a shooter using a compound bow, and was often able to place a second arrow (which I was holding in my bow-hand) into the kill zone as or before their first arrow arrived on target. After this simple test I would simply ask, “Now, who has the faster bow.” It was an eye-opener for many.

That’s only one of the many reasons why I prefer my longbow but the complete answer would be a full-blown article. If you want the whole story you will need to read my book.

Q. Dr. Ashby, with the heavy arrows you hunt with how do you cope with the longer shooting ranges we encounter out west?

A. I’ve done a fair amount of hunting in both the mountains and the open prairies and tundra; more than most folks. I’ve never found that a problem for me. You see, I have never needed to do any long-range shooting at game because I’m a better hunter than that. I always found it more productive to spend my time on developing my hunting skills rather than on long-range practice.