Arrow penetration

[Beendare]

We are finally starting to see some good info on arrow penetration on Youtube...instead of the crazies. Good performance is almost all about having perfect arrow flight.

This one is accurate all except the minor issue of the attitude of the arrow in flight real world. Arrows with avg FOC fly parallel to the ground while following the parabolic flight path he illustrates....unless they have massive tip weight, then they can fly with a nose down attitude

Hat tip to Lunghit on another site for recommending this vid.....the guy pretty much nails it.

 

[Long Cut]

Cool video.

I’m too stupid to break down and verify his math, but what I’m understanding is a decent FOC/Spine arrow that’s tuned with perfect flight will penetrate “best”.

Regardless, 33” or 42” of penetration, that’s a good amount for a whitetail deer. I’d favor trajectory over losing speed for a potential gain of 9”

My .02

 

[Trial153]

He does an excellent job on his videos.

 

[Beendare]

An avg foc arrow flies parallel to the ground but on the same arc as diagrammed.
Thats minor, Otherwise excellent vid.

 

[Jpsmith1]

Former Ashby 'disciple' here.

Anyone know that the second of his 12 Arrow Penetration factors is?

It's perfect arrow flight. Right behind structural integrity.

Even the Ashby guys fully recognize the need for perfect arrow flight at impact for optimal penetration.

Now, we can have a discussion about the ranking, but the first 3 or 4 factors were widely considered to not be optional. Building a solid arrow that was less likely to break on harder impacts. Arrows with good inserts and sleeves to prevent shaft splintering. Solid broadheads that were less likely to break or bend. Then making that arrow fly as perfectly as possible. Endless hours of bare shaft tuning to get a perfect launch, then putting the barest minimum fletching on.

I really don't think that some of these are terrible ideas to follow building an arrow.

Heck, I still follow a fair amount of it. 510gr at 28" long. I just don't build 700 grain arrows anymore. Arrow mass over 650 was the least important factor of the 12.


I'm definitely curious, having shot heavy, high FOC (23%) arrows at longer ranges, I've never seen evidence of deviation in flight or of the arrow flying tip down. I suspect it's possible, but I think it wouldn't happen until we're reaching some extreme ranges. Certainly on the fringes of what is ethical. I'd love to see good evidence of it, though.

 

[5MilesBack]

Anyone know that the second of his 12 Arrow Penetration factors is?

It's perfect arrow flight. Right behind structural integrity.

I'm not sure I've ever even read Ashby's stuff, other than what's been thrown around on the forums. But my top three arrow requirements have always been structural integrity (i.e. durability), consistency/accuracy, and perfect arrow flight......in no particular order. Of course with my draw length, penetration has never been an issue.

 

[Billy Goat]

I've heard it, but haven't understood it. How does an arrow fly tip down just because it's EFoc? The drag of the fletching should be correcting that. It might do it for the first bit, but the fletching will pull the back of the shaft behind the point unless it doesn't have enough drag.

 

[Bump79]

Former Ashby 'disciple' here.

Anyone know that the second of his 12 Arrow Penetration factors is?

It's perfect arrow flight. Right behind structural integrity.

Even the Ashby guys fully recognize the need for perfect arrow flight at impact for optimal penetration.

Now, we can have a discussion about the ranking, but the first 3 or 4 factors were widely considered to not be optional. Building a solid arrow that was less likely to break on harder impacts. Arrows with good inserts and sleeves to prevent shaft splintering. Solid broadheads that were less likely to break or bend. Then making that arrow fly as perfectly as possible. Endless hours of bare shaft tuning to get a perfect launch, then putting the barest minimum fletching on.

I really don't think that some of these are terrible ideas to follow building an arrow.

Heck, I still follow a fair amount of it. 510gr at 28" long. I just don't build 700 grain arrows anymore. Arrow mass over 650 was the least important factor of the 12.


I'm definitely curious, having shot heavy, high FOC (23%) arrows at longer ranges, I've never seen evidence of deviation in flight or of the arrow flying tip down. I suspect it's possible, but I think it wouldn't happen until we're reaching some extreme ranges. Certainly on the fringes of what is ethical. I'd love to see good evidence of it, though.

I agree. The thing with the Ashby reports is that he has several critical caveats that he lays out. Perfect arrow flight & trajectory. All of it is valid for the most part - the problem is that it doesn't recognize that when it comes to engineering there are always tradeoffs. It's more their application that is flawed than the studies themselves.

The question to me is "What is perfect arrow flight"?
To me it means 3 things: Flight (flying straight), precision (group well) and accuracy (hitting behind the pin). Believe it or not you can have poor flight and still group reasonably well and sight in to it at close range. I took my rest 50 clicks out for testing the other day and was only 1.5" out at 15 yds with a large unvented fixed blade. Very eye opening. It's just like how a well designed mechanical can cover up a bad tune or spine. A lot of people claim perfect arrow flight but watching them shoot you know there's now way they even have a ability to shoot a fixed blade well enough to even know if their tuned. They shoot a group at 30 yards and it's a spray of arrows and the fixed blade is somewhere in the midst of that spray.

I guess I have high standards - but that head better hit as close the pin about no matter what I do. I've played around with my bow out of tune, gripped the heck out of it, tightened down my cable guard to add torque, but myself in unrealistic shot positions to test at maximums. It's unquestionable that blade surface area equals forgiveness. I actually now tune with a head with a lot of surface area now because it fine tunes my setup as it planes off course easier. Then I screw on a more forgiving head to hunt.

When you read the latest Ashby report and a Sevr 1.5 is given the same exact flight rating as a massive 3:1 (or even 1.5:1) unvented fixed blade. That's fairy tale land. Of course, the mechanical has significantly better flight characteristics. If you eliminate blade exposure you get better flight. If you add vents you get better flight. If you shorten the head you reduced surface area and get better flight. These are FACTS.

But everything comes at a cost, in this scenario as most every there's no solutions only tradeoffs. In real life there's so so much room in the middle ground. It's not light fast dull mechanical with poor arrow flight vs heavy sharp single bevel fixed. There's a whole pile of 100-125 (150 too) broadheads that are durable, sharp and fly significantly better than a massive 3:1 unvented broadhead.

Yes, you want a head to performs well on bone. But we've got to acknowledge that if it has better flight characteristics - you're reducing the odds of hitting bone.

https://www.ashbybowhunting.org/s/2022_ABF-CASE-STUDY_FINAL12072022.pdf

 

[Bump79]

We are finally starting to see some good info on arrow penetration on Youtube...instead of the crazies. Good performance is almost all about having perfect arrow flight.

This one is accurate all except the minor issue of the attitude of the arrow in flight real world. Arrows with avg FOC fly parallel to the ground while following the parabolic flight path he illustrates....unless they have massive tip weight, then they can fly with a nose down attitude

Hat tip to Lunghit on another site for recommending this vid.....the guy pretty much nails it.

I've been messaging back and forth with him some. I'm interested to see where his series takes him. Good dude - a little concerned he's going down the full Ashby rabbit hole without presenting the contradictions. Lethality isn't just about penetration. Arrow flight is number 2 after not falling apart but they don't even address it.

Everything has tradeoffs. High velocity with fixed = low forgiveness. Big unvented broadheads = low forgiveness. Heavy arrows = higher range error. Mechanicals = lower penetration. Extreme FOC = tough as hell to tune. Small cut diameter = small holes and reduced odds of clipping something vital. It really is a balancing act and people want a simple explanation for a complex problem. The only answer to that is while there's madness in crowds - there's also wisdom. There's a reason that the vast majority of setups sold are moderately weighted and have a forgiving 3 blade screwed on it.

I'm thinking about doing my own video as I've really gone deep in some of the math on range forgiveness and (just a presentation really).

 

[Dennis]

Heck, I still follow a fair amount of it. 510gr at 28" long. I just don't build 700 grain arrows anymore. Arrow mass over 650 was the least important factor of the 12.

Thanks JP, and hopefully everyone actual reads the Ashby 12 Penetration Factors and the supplemental 2021 and 2022 reports from testing in animal tissue. Arrow mass over 650 grains is the 12th factor and hopefully everyone realizes it moves up to about number three if heavy bone is encountered. If no heavy bone is encountered its number 12.

I think Lucas Palmer has been doing a good job on his educational videos. His recent video on heavy vs light arrow trajectory at 60 yards show how little the difference really is which is nice to see it documented.

His videos seem to follow along with both the Ashby study and Ranch Fairy testing which is all fact based. Thousands of hours of testing in actual tissue and science that lays out the facts.

Bump79 is correct that perfect arrow flight is important and so is accuracy and thanks for sharing the supplemental report. Good luck on your videos.

My goal is to balance all the factors and my accuracy within my effective range.

 

[Dennis]

Another good video report is from DYI Sportsman on arrow flight and deer reaction time. Fact base testing is great to see what really happens and how much arrow speed beats a deer at what yardage.

 

[Beendare]

I think this guy does a great job in his series.

IMO, one way to think about this stuff without the math is;
FOC creates the balance point on an arrow that all of the oscillations, fletch and direction hinges on. Push that point too far in one direction and it destabilizes the arrow- simple. All of the experienced shooters in every archery discipline tune for perfect arrow flight with avg FOC.

Arrow tuning is a bell curve. It makes sense that when we go to far from the center of the curve, we lose a good tune and arrow energy. This was proven in their book “ Archery the technical side” back in the 40’s with testing done by the original rocket scientists Hickman, Goddard, Nagler and others

 

[Bump79]

@Beendare @Dennis here's the summary from his velocity video. I like this guy a lot - the problem is so much YouTube content is being driven to push you to their conclusion.



The difference in range error at 60 yds between the 450 grain arrow and the 600 grain arrow is 1.8-2.2". An entire 2" diameter broadhead high or low in terms of vitals you're hitting. I'd say that's something.. As a percentage - the 600 grain arrow is 29% less accurate (hitting where you thought) than the 450.

That's straight off the top without any of your errors taken in. So how big is your group at 60 yds with broadheads in the field? Well mine is probably realistically 3"-5" in the field. We'll call it 4". So now you're at a total error of 6". How do you feel about that at full draw? You're aiming middle on that bull and could hit high scapula or leg.

My vote goes for as close behind my pin as possible. There's a reason every pro shooter shoots fast. They run this equation out daily. Not that you don't give up things with velocity - you absolutely do. Shoot a little slower and your broadheads will group better. Shoot a little heavier and you'll get better penetration on average.

Ranch Fairy testing which is all fact based.

I'm going to disagree with this. RF is very, very biased. In fact - he goes through that entire animal reaction video trying to deny what is presented to him and was arguing with me about it the other day. I've done the same exact physics and the opportunity for an animal to move is greater with slower arrows. That's just a fact. He says he's watched hundreds of videos to analyze - well guess what. The cameras people are filming hunts with are like 140 fps. The frame rate just isn't high enough to be able to tell. He's trying to say he's measuring a you're bore size of your block with a ruler then telling you it's bored over .040" not .060". Are you going to buy pistons on that recommendation? I'd recommend not.

He's right about a lot - Heavy arrows penetration more. A lot of mechanicals suck. Mechanicals don't penetrate as well as fixed. Aim further forward generally. Tune your setup. Shoot good broadheads. Sharpen your broadhead. But animal reaction and trajectory is not one of those things. He just doesn't do well with presenting the other side of the story and is not an objective person to rely on. He's deliberately leading you down one path and won't accurately present the other side of the story.

 

[Dennis]

Bump79, I do not see any loss of accuracy in heavy arrows vs light at distance in my own shooting, however maybe your results are different. I have never attempted to conduct a scientific test to see any changes other than my own ability. When I achieve perfect bare shaft arrow flight at close range and then extended bare shaft shooting, testing and grouping at 50 yards my arrows grouped has good or better than fletched shafts. Finished arrows did just as good just lower because of additional drag with fletching and broadheads.

I think we all will be looking forward to seeing your video providing facts that prove your conclusion. Do you have a timeline?

 

[Bump79]

Bump79, I do not see any loss of accuracy in heavy arrows vs light at distance in my own shooting, however maybe your results are different. I have never attempted to conduct a scientific test to see any changes other than my own ability. When I achieve perfect bare shaft arrow flight at close range and then extended bare shaft shooting, testing and grouping at 50 yards my arrows grouped has good or better than fletched shafts. Finished arrows did just as good just lower because of additional drag with fletching and broadheads.

I think we all will be looking forward to seeing your video providing facts that prove your conclusion. Do you have a timeline?

Sometime in the next month. I'm not a video guy or have a desire to become an influencer of sorts so expect a lot of math and just examples like he did in the field. I've done it before and it's extremely well established. Heavy arrows move slower, arrive later and have more range error.

Accuracy as that's the ability to hit where your aiming. Range error is a reduction in accuracy. You're talking about precision - IE grouping well. I never said you can't group well with a heavy arrow, you should be able to as well or actually easier. That is unless you're broadhead is a massive unvented 2:1 or 3:1 then I'd debate it..

Again, I like this guy but he just glossed over it and said it was "small" or not significant. I'm just pointing out that it's not small and is significant. Everything I stated was in his video, I came up with no numbers and literally took them out of his video. The problem his presentation was in Ranch Fairy light fashion where it's leading you to a conclusion. One that sounds like you're already at so it feeds into your bias.

My point is that we need to be honest about the facts on the ground. Per his numbers - a 5 yd range error at 60 yards (too far IMHO) with the 450 grain arrow has a 6.3 to 7.5" vertical error. Ask yourself - how much more room do I have vertically? Do I have 2" more in the vital v without hitting bone? Why should you increase the odds of hitting bone?

Slow arrows and long range don't mix on game. You need to limit your range and be fine with that. Again, I just want facts to be spelled out. Slower arrows arrive later and have more range error. They do retain some more momentum & KE but you'll need it if you hit bone you would have just avoided.

 

[Dennis]

Range error is a reduction in accuracy.

If I understand your point it is that a 2" additional drop between a 450 grain and 705 grain arrow is your definition of reduced accuracy? If we both ranged the target at 60, but it was really at 65 the 450 grain arrow would be a killing shot low 7.5" and the 705 would hit 9.8" low or 2" lower in bone. On the other side is a 705 grains exceeds the bone breaking threshold and thus still a killing shot one might assume. However even with an elk kill zone of 12" we would still both miss the kill zone anyway. Sounds like you just have a different bias.

While I strive for precision in my shooting I would be hard pressed to see a 2" difference at 60 yards. My goal is more like can I hit a paper plate every time at 60 which is my limit on animals anyway.

I just watched "Elk Shape" video "It was Embarrassing" which seemed to be what I normally see on 3D ranges with regular guys. These are ranged targets with a good shooter and yet arrows hits are not perfect as you say right behind the pin. I don't think he or I could ever rule out that we might not hit bone.

Below is an attached chart from the 2023 Rockslide Cold Bow Challenge that is of every day bowhunters shooting whatever their set up is. They all have stated their MER and range estimates are or should be accurate. On average almost everyone makes a vital shot 4 out of 5 shots with compound bows.

 

[Jpsmith1]

Thanks JP, and hopefully everyone actual reads the Ashby 12 Penetration Factors and the supplemental 2021 and 2022 reports from testing in animal tissue. Arrow mass over 650 grains is the 12th factor and hopefully everyone realizes it moves up to about number three if heavy bone is encountered. If no heavy bone is encountered its number 12.

I think Lucas Palmer has been doing a good job on his educational videos. His recent video on heavy vs light arrow trajectory at 60 yards show how little the difference really is which is nice to see it documented.

His videos seem to follow along with both the Ashby study and Ranch Fairy testing which is all fact based. Thousands of hours of testing in actual tissue and science that lays out the facts.

Bump79 is correct that perfect arrow flight is important and so is accuracy and thanks for sharing the supplemental report. Good luck on your videos.

My goal is to balance all the factors and my accuracy within my effective range.

I agree that it's a well presented video.

I want to make it super clear that I'm a crap archer (part of why I went heavy to begin with) and I'm not super great at tuning. I'm definitely not putting myself out there as anyone whose advice should be followed.

I went down the rabbit hole after struggling and losing like 3 bucks to a combination of bad shots, piss poor tuning, improper broadhead selection/care/maintenance and poor fieldcraft.

Watching that red nock walk off into the setting sun hanging out of the third buck I'd managed to put an arrow in while the thunder rumbled behind me was shattering. I seriously considered a nose dive out of the stand.

So, questions like "how to maximize arrow penetration" led me to Ashby and Grizzlystick.

Built out arrows weighing 692. Single bevel heads, all the "cool kid" stuff. Managed to screw up a whole bunch more before deciding I wanted more forgiveness in my range estimation than i wanted the ability to smash bone.


My point was just that the 'Ashby guys' consider perfect arrow flight, defined by them as the arrow traveling with the point and the nock in perfect alignment with the direction of arrow travel, as super critical. More critical than nearly anything else.


I am very curious about EFOC arrows flying tip down. I'm not super sure about that.

 

[Dirt_Fishh]

I'm super new to this but some really nice info + thoughts here! Thanks

 

[Bump79]

If I understand your point it is that a 2" additional drop between a 450 grain and 705 grain arrow is your definition of reduced accuracy?

My example was just an increase of 150 grains as he presented from 450 to 600. I'm highly suspect of his 705 grain arrow number - an increase of 105 grains would not lose only 2 fps. For example Ranch Fairy's data showed a loss of 17 fps with a 100 grain increase. The range error would be much larger than the 600 grain arrow in the realm of another 1"+.

But yes, absolutely! This is the technical definition of accuracy - not mine. Accuracy is hitting where you aimed and precision is grouping together. Think about it like this - you can be shooting extremely well but you're sight tape is off - then you're precise but your missing your mark. Range error is missing your mark and therefore not accurate. If you're shooting an unknown 3d course and can't judge range well (like me) then your not going to score well.
https://statisticsbyjim.com/basics/accuracy-vs-precision/

If we both ranged the target at 60, but it was really at 65 the 450 grain arrow would be a killing shot low 7.5" and the 705 would hit 9.8" low or 2" lower in bone. On the other side is a 705 grains exceeds the bone breaking threshold and thus still a killing shot one might assume. However even with an elk kill zone of 12" we would still both miss the kill zone anyway. Sounds like you just have a different bias.

I agree that a vital height of an elk is around 12". Depending your aim point - if hitting low one would "maybe" be in vitals and one could just destroy a leg bone. Hitting high one might be in spine and one my just need to pass through scapula.

This is why I said I think a 60 yard shot is too far. It would have to be a perfect scenario for me - IE perfect range on his body, low wind, his head up looking away, maybe looking at a different elk who's making some noise, maybe mid bugle. For me it's really got to be perfect. This is being consistent with the same logic as a heavy arrow taking longer.

50 yards for me and that's with a faster arrow and fixed blade. Because of range error & time to target.

Per his numbers - a 5 yd range error at 60 yards (too far IMHO)

I don't think he or I could ever rule out that we might not hit bone.

Yes, I agree. But the range error with 600 grains is still 29% less at 60 yards. Our pie plate group is now 2" lower. Meaning you just stacked your errors on top of each other. Your arrow & broadhead can still be durable, super sharp, single bevel if you like and weigh 450-520 grains and fly fantastic. The worst case scenario is I hit near side bone with that setup and I don't get into vitals. In that case - that's the "best" worst case scenario in my book as he'll shake that off. Worst case is a shot too far back.

Sounds like you just have a different bias.

I do have a bias. But I'm truly trying to challenge it and these are based on the facts on the ground. I'm not here saying that guys should shoot a mechanical at over 300 fps. I'm saying there's actual tradeoffs taking place and the Ashby disciple videos aren't being objective. I'm in no way denying that a heavy arrow will penetrate better. While it retains KE & M better downrange, it will get there slower, give the animal more time to react (does quiet things down though) and you'll have more range error. So the question is with your setup how much penetration do you need? Well fortunately like Lucas in the video - I've a 30" draw and shoot 70#+ so at 50 yards I've got more energy than a lot of killers do at 30. So for me - I choose range forgiveness. That's not an option for everyone. But as your energy goes down - the range error increases. A 600 grain arrow for my uncle at 26" 55# is like me shooting 900 grain arrows (or something). He ought to move up in grains and get CLOSE.

This isn't that controversial - 280 fps is recommended by nearly everyone. The middle ground just isn't as sexy. It's not some industry conspiracy that everyone winning professional 3d shoots scores better with a faster arrow. This is why they have limits on speed in some shoots. If it wasn't an advantage they wouldn't have that limits. These are all really well established things. There are real tradeoffs - Pick your poison.

I'm in no way saying that you shouldn't shoot heavy. But I will say I'd hold onto that rangefinder tight! Or just be honest about the range error and shoot 45 yds max and not 60 yds. I hunt by myself so I pre-range and still often am plus or minus 5 yds. I'm just not that good at it. For me, I've nearly lost a bull from 5 yard range error. Luckily I backed out as it was near dark and he was still alive in the morning but unable to move 40 yards away so could finish him off. We were all mind blown that he died - very bottom of the chest cavity. 2" lower and he would have been. Had it gone the other way and be high my arrow would need to plow through both scapula's to get through. I've also missed bulls due to range error.

 

[Beendare]

JP, I think its admirable you did what you think best to improve arrow penetration.

The fact is, you don’t need a 600g or 700g arrow to kill a whitetail…thats a laughable claim when we see trad guys blowing through critters with very low energy setups. I have personally blown 2 arrows through a moose with a 46# recurve that barely makes 30 KE And didn’t have penetration issues with that bow Using a 2 blade.

I think this guy in the vid is partially right when he states penetration problems are due to bad arrow flight, especially considering many of the mech guys don’t BH tune.

Pair an inefficient BH with an untuned arrow and its no wonder guys have penetration problems. The mech head guys that do tune don’t have a problem.