Arrow penetration

[Bump79]

Same here. Had to dig for this a bit, but I bought that RF test kit Ethics used to sell a few years ago and chronoed the arrows I had at the time with all nine field point weights. I didn't get KE differences that big... less than 2% between the lightest and heaviest arrow. Only three shots per weight, and there was more variance in the velocities than I would have liked to have seen. Some of the arrow weights spit out all three readings within 1 fps, others there was 3 fps difference between the slowest and fastest for that arrow weight. Wish I could have done this with the Labradar I borrowed last year. Anyway, the table is below, and though there are hiccups likely due to an imprecise speed measurement device, the trend definitely goes in the direction of more weight gives more KE.

TAW	Avg fps	KE ft-lb
516	292.7	98.2
541	285.3	97.8
566	279.0	97.9
591	274.0	98.5
616	268.3	98.5
641	264.7	99.7
666	258.7	99.0
691	254.3	99.3
716	250.7	99.9

Some good data from PNL testers.

 

[entropy]

Might not apply, but when shooting something I know is weak or very weak, I have had a fair amount of variation over a chrono. I figure that shaft is flexing pretty good.

At around 7-8 gr per # with good spine, I generally get very consistent velocity. Like .3 variance over 3 shots.

That could certainly be a contributing factor... but I'm more of the opinion that my chrono is not very good. I've sent everything from 440 grain 250 spine arrows (definitely not underspined with a 14 gr insert and a 100 gr field point) to arrows similar to the max on the table. Most of the time it doesn't vary much... but I've also seen 79 fps arrows and 993 fps arrows, in addition to the normal 3-4 fps variation.

I borrowed a Labradar last year, and that thing didn't vary more than 1 fps over the 30 or so arrows I shot alongside it. Whenever I run across a deal on one of those, or one of those new Garmins, I think that's the way to go.

 

[Billy Goat]

That could certainly be a contributing factor... but I'm more of the opinion that my chrono is not very good. I've sent everything from 440 grain 250 spine arrows (definitely not underspined with a 14 gr insert and a 100 gr field point) to arrows similar to the max on the table. Most of the time it doesn't vary much... but I've also seen 79 fps arrows and 993 fps arrows, in addition to the normal 3-4 fps variation.

I borrowed a Labradar last year, and that thing didn't vary more than 1 fps over the 30 or so arrows I shot alongside it. Whenever I run across a deal on one of those, or one of those new Garmins, I think that's the way to go.

When I get a wide variation, it's typically from lighting.


I haven't put arrows through my labradar. My shooting chrony lines up with AA and has been doing what I need.


But I'm working on something that is based around spine and I might try getting chrono readings at 65-75 yards.

 

[Mighty Mouse]

My 475gn arrow going 288fps has roughly 88 ft lb of KE and 0.6 momentum.

If I bring the arrow weight right up to 650gn, it estimates 230fps, which gives me 76 ft lb of KE and 0.66 momentum.

KE always increases with increasing arrow weight. It's a slight increase though; slight enough to be masked by chronograph error in some cases. Assuming KE remains constant is close enough for all practical purposes. Momentum does change significantly with arrow weight, but whether or not momentum is a useful metric is an open question (I tend to think it's irrelevant). Many online arrow calculators apply a fixed fps per grain speed loss assumption and often give erroneously low speed and KE numbers for heavier arrows. The calculator on the ABF website is good...much of the rest of the site is not, however.

 

[Beendare]

I don't know when I turned into the sort of bloke who crunches numbers, but here we are.

Yeah, its funny….. seems to me thats part of the evolution of a bowhunter. We start to learn more, try to apply the numbers and formulas…blah blah blah….down the road we evolve to a tuned setup that balances trajectory and all the other variables- By tuning and testing …..not by doing the math.

Then we realize…longbow and recurve guys are shooting through critters effortlessly…and with 1/2 of the energy in a compound.

If I asked a bunch of the experienced guys I know what their KE, or FOC is…they not only couldn’t tell me…but they would snicker and shake their heads.

 

[Tilzbow]

When I get a wide variation, it's typically from lighting.


I haven't put arrows through my labradar. My shooting chrony lines up with AA and has been doing what I need.


But I'm working on something that is based around spine and I might try getting chrono readings at 65-75 yards.

The accuracy and consistency of my chronograph numbers improved dramatically with a light kit and moving shooting through the chronograph indoors. Outside, like you, and the person you quoted, noted I would get wide swings especially when the sun was low in the sky.

 

[Billy Goat]

The accuracy and consistency of my chronograph numbers improved dramatically with a light kit and moving shooting through the chronograph indoors. Outside, like you, and the person you quoted, noted I would get wide swings especially when the sun was low in the sky.

Cloudy day is actually the best for outside. No defelctor things, sometimes I'll put straws in place of the rods to line things up better. Florescent lights really mess with them, a light kit is almost required for indoor use in my experience.

 

[Wilderlife]

Then we realize…longbow and recurve guys are shooting through critters effortlessly…and with 1/2 of the energy in a compound.

100%.

Picking up my new longbow tomorrow which will be around 45# @ 28in. I'll shoot an arrow somewhere around 450-500gn and be very confident in it.

 

[ResearchinStuff]

Cloudy day is actually the best for outside. No defelctor things, sometimes I'll put straws in place of the rods to line things up better. Florescent lights really mess with them, a light kit is almost required for indoor use in my experience.

same experience here, i won't even try my optical chrono unless it's a consistently overcast day. The straw trick is a good one, haven't tried that before.

 

[MattB]

Cloudy day is actually the best for outside. No defelctor things, sometimes I'll put straws in place of the rods to line things up better. Florescent lights really mess with them, a light kit is almost required for indoor use in my experience.

I’ve learned that lesson the hard way. Our garage is really well lit, but I have to rig up a separate work light with an incandescent bulb to get to to work.

 

[Wilderlife]

I've just taken up a bit more work doing writing for a shooting magazine here. I'll need to review some rifles and the editor told me I can get equipment at very good prices. Currently using a Caldwell chronograph, which works OK, but one of those new Garmins is tempting me, BIG TIME.

 

[Bump79]

This is an interesting video. Compared to most tests that use ballistic gel or just cardboard - they used hide, small layer of foam, small wood board then actually food jello. So not as much friction as a lot of tests out there. Still being stopped a lot by momentum. Little to no difference shown.

Where the heavy arrow and momentum would come into play would be a sudden stop - causing a larger impulse force. But everyone needs to realize it's not magic. There's no fairy dust to sprinkle on your arrows. We've got to ask ourselves.. If nearly every test medium we can think of doesn't show these gains that are claimed. How large are they in real life? Will the Ashby foundation really put out data that contradicts their entire thesis? Or will this non-profit keep using the money donated to them to go on exotic hunts?

One thing that I've never heard the Ashby folks bring up is that in the latest 2022 supplemental update a Sevr 1.5 penetrated a minimum of 7" into a cape buffalo... Why in the world are we even talking about on penetration deer/elk/antelope for? It seems completely ridiculous given this data. Again, a 1.5 inch cut unsharpened MECHANCIAL penetrated a MINIMUM of 7" into a cape buffalo. If you're shooting a cut on contact fixed broadhead - regardless of arrow weight - is this a conversation we should be wasting our time discussing?

My favorite part of the report is that their ratings are such a joke. A 3:1 unvented 2 blade has the same flight rating as a Sevr 1.5. Both "A". This is so wrong it can't be explained away without flat out lying. Yes, a Sevr didn't penetrate as far. But at least be honest and say that a head that barely has exposed blades will fly better.

 

[Beendare]

Does 7" into a Cape buff even get into the rib cage? It wouldn't on the Aussie Water Buff I shot.

Seems to me the Ashby Foundation is a bit of a joke.....in fact, so many of these influencers try to make this stuff more complicated than it really is to inflate their celebrity.........don't you think?

 

[MightyWhitey]

So if you recurve/longbow guys are shooting 10-11gpi per pound of draw weight and blowing through animals effortlessly and have no issue with trajectory, why are you having such a fit about a compound guy’s trajectory shooting a similar gpi per pound of draw weight?

Or why aren’t you compound guys telling the recurve guys their arrows are way too heavy and inaccurate?

I can’t talk KE, momentum numbers so maybe there’s something I’m missing. But if we can all agree that Structural integrity, perfect arrow flight(tune), and sharpness are the most important factors of any weight arrow, then why do the heavy ones with all three of those factors coming out of a compound get everybody so worked up?

 

[Bump79]

So if you recurve/longbow guys are shooting 10-11gpi per pound of draw weight and blowing through animals effortlessly and have no issue with trajectory, why are you having such a fit about a compound guy’s trajectory shooting a similar gpi per pound of draw weight?

Or why aren’t you compound guys telling the recurve guys their arrows are way too heavy and inaccurate?

I can’t talk KE, momentum numbers so maybe there’s something I’m missing. But if we can all agree that Structural integrity, perfect arrow flight(tune), and sharpness are the most important factors of any weight arrow, then why do the heavy ones with all three of those factors coming out of a compound get everybody so worked up?

Trad guys limit themselves to 15-20 yds typically. They generally fully acknowledge that out past that distance their trajectory is a problem. Why? Because their going slower and they don't deny that it going slower = more range error.

I agree that those factors are the most important. If you listen to certain people on YouTube and the notorious Ashby Foundation - it is unethical to hunt elk with my 445 grain arrow going 294 fps out of a 70# compound with a 30" draw. Even I bumped up my weight 50 grains I would be in the "cautionary" zone. 150 grains add and I'd be "acceptable" after increasing my weight 33%. This chart is complete non-sense as it doesn't take into account the archer specs, the bow or shot distance. Just complete junk - it doesn't even match their 650 grain bone breaking threshold. The Ashby Foundation is setup for 3 things - to give them status, make heavy components and arrow manufactures money and to get them free hunting trips to exotic locations. A trifecta of bias.

If I was a low energy shooter concerned about my penetration you'd go to this chart, see you need a 650 grain to hunt elk then you've spent pile of money then realize that the trajectory doesn't allow your 192 fps bow to shoot 30 yards without insane arrow drop that isn't acceptable. So then you either have to limit yourself to 20 and in or sell those arrows and get a lighter arrow that any normal shop would have set you up with. Now your out money and time. Who won in this scenario? Not the hunter.

As I demonstrated multiple times the range error is real, the opportunity for a deer to move is more and no matter what you do to that compound - it's never going to be as quiet as a recurve/longbow. Just be honest about the tradeoffs with a heavy arrow. It's going to get there in a longer time giving the animal more opportunity to react to your still loud bow, if you don't have a perfect range it will amplify the error but it will have more momentum and KE when it gets there. The question is how much more penetration do you need with your compound that already has more KE & momentum than the recurve?

I argue - that we're effectively all arguing about something so silly it's like arguing that a diesel 3/4 ton diesel should limit itself to the same speed limit while towing 6k pounds as a Tacoma. It's the same trailer to be towed but the diesel has 1000 ft-lbs of torque vs the 300 ft-lb of the Tacoma. The Tacoma is maxed out and is struggling along at 55-60mph. The diesel isn't anywhere near payload and barely above at idle if going 60 and it's perfectly capable of safely going faster. While this analogy isn't perfect - it's a good example.

If the force to get through the animal is the same (effectively) and a 550 grain arrow out of a longbow/recurve (Tacoma) blows through everything in NA with way less momentum and KE than the compound (Diesel). Why would you not go a little faster or cut a little more (tow more weight) if you have more? Why can't you go faster and get the advantages if you have the right tool?

I can logic my way into setup where compound guys bump up their arrow weight and put a larger cut size broadhead on the front. Or a mechanical. This is a consistent thought process - IE tow more weight with the diesel in my example. If you have nearly 2x the KE & momentum - You could increase the cut size 50% by using a 4 blade vs the 2b that passes through everything with a recurve. Or just shoot a mechanical. It's just illogical to me for someone to advocate for someone to shoot a smaller cut broadhead, with more range error and time for the animal to react so long as your flight is still perfect. Why not take advantage of what we've got?

My vote is to use normal compound weights - the weight you can just walk out of the archery shop with. It's not a conspiracy that most all arrows off the shelf will land you around 400-500 grains. Increasing in weight with stiffer spines as a bow with more energy needs a stiffer arrow. Almost like it is purposefully designed that way by experts and engineers.... crazy.

My point isn't to nock the guy who shoots this heavy setup - it's nocking the guy who is advocating for others to shoot their setup and saying how magical it is. Just say you like being a contrarian and that's fine. But be honest about it.

 

[AkRyan]

@Mighty Mouse

I think to get the tip down, it's a loss of forward momentum coupled with the increased drop. It needs to slow to where the drop is actually giving air resistance to the fletching and causing it to hold the back of the shift higher.

I'd assume this happens well outside of hunting ranges.


So I guess it's something that can happen at any point past the apex, but it's gotta be pretty insignificant and is more due to fletching size over point weight.

If you watch some trad bow guy shoot heavy (600+g) setups you will see the tip down, the low velocity has a harder time fighting the effects of gravity and pull the front down, there larger fletching at the rear of the arrow grabs air and forces the rear of the arrow down. It's all a balancing act. If you shooting 60lbs runs 400g ish setups with 15% foc and you will have full freezers, at 70lbs run over 450g with the same foc parameters.
I just built a set of x10 parallel pros at 27.5 with 75g match inserts and tac vanes, comes in at 459g and 17.3% foc. Wife runs rip tko at 26.5 with 50g insert and blazers, low 400s and over 15% foc.

 

[MightyWhitey]

Beendare, are you only shooting 20yds and in? Trajectory is part of it, aiming method, holding weight and release method greatly are bigger factors that limit range more than trajectory. If it was trajectory only I think they’d be shooting lighter arrows, no?

I’m not arguing about the trade offs, but I don’t think they’re as drastic as the Ashby haters make it out to be and that they’ve got some devious plot for self gain any more than they accuse the archery industry of.

I’ve got a leg on both sides of this fence. I shoot a compound, but I it shoot instinctive and have been for about 20yrs. For the longest time I shot a gold tip 7595 with a 125gr coc head out of a 70lb bow. And my max range was about 30yds. Never had any penetration trouble, but only hunted WT and took broadside or quartering away shots. I did have some structural integrity issues but I just thought that’s the way it was.

About 5 or so years ago I got interested in this Ashby stuff and liked the thought of a tougher arrow that was more leathal in more situations (shot angles). I was also looking for a new bow at about that time and got a 80lb to try to push this new heavier arrow at similar speed (trajectory). I settled on a 665gr arrow that ended up doing 240fps. (Making my 3/4 ton work a little.) Im shooting better at longer ranges than I ever have. Not saying it’s because of a heavier arrow at all. It’s from Tom Clums coaching and more practice.

So I don’t think it’s fair to say a heavier arrow is less accurate. It’s the yardage estimation that lacks accuracy.

It seems illogical to me to up your weight just to put a head with the least structural integrity (mechanical), since we already agreed that that was more important than weight. And aren’t heads with wider cuts less accurate?

As far as different penetration tests go, maybe I’m wrong but isn’t the Ashby foundation the only ones shooting arrows into whole animals for testing? I agree that they use some strong language in those charts etc that pisses people off and I get it, I’m sure more animals have died with lesser weights than what they’re saying is acceptable.

Anyway we can point the finger back at each other forever and I’m not sure there’s a right answer. We just each have to choose what limitations we’re comfortable with. I don’t want to have to pass on a 30yd quartering to shot and you probably don’t want to have to pass on a 65 but maybe it’s 70yd shot. I doubt your faster lighter setup gives you any more advantages than my quieter heavier setup does. To each their own I reckon.

 

[Billy Goat]

If you watch some trad bow guy shoot heavy (600+g) setups you will see the tip down, the low velocity has a harder time fighting the effects of gravity and pull the front down, there larger fletching at the rear of the arrow grabs air and forces the rear of the arrow down. It's all a balancing act. If you shooting 60lbs runs 400g ish setups with 15% foc and you will have full freezers, at 70lbs run over 450g with the same foc parameters.
I just built a set of x10 parallel pros at 27.5 with 75g match inserts and tac vanes, comes in at 459g and 17.3% foc. Wife runs rip tko at 26.5 with 50g insert and blazers, low 400s and over 15% foc.

I suspect that's more a tuning issue.


I can shoot 600 gr bareshafts (out of my recurve) and they don't fly point down. The effects of gravity are the same if it's going 100 fps or 1000 fps. Only difference would be drag from the vanes is increased with higher speed, which would bring the back of the shaft down.

But that means the arrow is launching/recovering point down which is out of tune.

 

[Wilderlife]

So if you recurve/longbow guys are shooting 10-11gpi per pound of draw weight and blowing through animals effortlessly and have no issue with trajectory, why are you having such a fit about a compound guy’s trajectory shooting a similar gpi per pound of draw weight?

Or why aren’t you compound guys telling the recurve guys their arrows are way too heavy and inaccurate?

I can’t talk KE, momentum numbers so maybe there’s something I’m missing. But if we can all agree that Structural integrity, perfect arrow flight(tune), and sharpness are the most important factors of any weight arrow, then why do the heavy ones with all three of those factors coming out of a compound get everybody so worked up?

I don't really want to shoot a trad bow further than about 25 metres on animals. A much faster arrow (among other things) gives me a much further point on, and this annoys me for hunting. I have a setup I use for target stuff and it launches a short arrow at 195fps, which gives me a point on around 45 metres, so my maximum gap is around 22 metres, which is something like a 6ft hold under. I'd much rather have a closer point on so the maximum gap I have is far less.

Yes, longer arrows, crawls, and where I anchor, also determine what my point on is, but the other point I'm making here is that I tune my bows and hunt in a manner that takes as much guess work out of my trajectory as possible, and that then means I don't/can't shoot that far.

With a compound, the potential for accuracy is far higher, and being able to take advantage of a flatter trajectory is much easier. If I were shooting a significantly heavier arrow, I may only be able to get my sight tape out to about 80 metres, but I can get it out much further than that at a moment - yes, this also has a lot to do with the type of sight and pins, etc.

My point is, a trad bow can certainly shoot 60 metres accurately, if the person is up to the task. I'm not, probably never will be, and I'm OK with that. The way my compound is setup right now, 60 metres isn't really what I'd call a long way. Sure, it is if we're talking hunting, and I doubt I'd ever shoot something that far.

 

[Bump79]

Anyway we can point the finger back at each other forever and I’m not sure there’s a right answer. We just each have to choose what limitations we’re comfortable with. I don’t want to have to pass on a 30yd quartering to shot and you probably don’t want to have to pass on a 65 but maybe it’s 70yd shot. I doubt your faster lighter setup gives you any more advantages than my quieter heavier setup does. To each their own I reckon.

I agree we shouldn't point fingers at each other - to each their own. That's been my entire point of my comments. Fast and light arrows and mechanicals have downsides. So does heavy arrows - the balance of which is up to the shooter. They aren't a magic wand that just allows for any shot presentation. We just need to agree on reality - If Ranch Fairy and Ashby won't give in to reality I'll keep beating this drum to counter their bad information to whoever will hear it.

Personally, I'm about done with quartering to shots. Not because of bone but because of the more limited error to the back of the animal. I'd be extremely hesitant on deer, elk or antelope to take a 30 yard quartering to shot. Especially with an arrow moving 240 fps. Hard no for me but not because of bone - because of guts.

Sounds like we have similar energy - here's some food for thought. Your arrow will have more KE & M at the target than mine in the neighborhood of 18% or so. Giving you around 24% more momentum and 2% more KE. Pretty sweet right?


However, you've given it 22% more time to react. Some of that is taken up by the sound and reaction time - leaving as a percentage your arrow having 46% more opportunity for the animal to move.


So the question is - if the animal decides to move. How far will it move? At only 30 yards the ability for the animal to drop with gravity (head up) would be 4.8" more than mine. If it decided to spin and takeoff like a track sprinter at the sound of the shot - it could move 2.7" more than mine. That's a large error considering vital size. Since the animal started moving pre impact you're also losing more energy and momentum.


Given this information - I feel much more comfortable with my fixed blade faster setup at 30 yards as I'm significantly more likely to hit the animal where intended and it will still handle some bone. Both have tons of energy and momentum (more than Ashby ever did) and neither setups are guaranteed to get through a knuckle. If I hit near side bone and don't get in - then then that is the absolute best case of the worst cases. That animal will most likely live. If you gut shoot it, it will most likely die. If I gut shoot it - at least it was a 3 or 4 blade and I might just put it down quicker. If I was you I'd still stick to that 20 yard range.. but to each their own.

Just to be really clear - I don't advocate for everyone to shoot 294 fps with a fixed head. If you're form isn't the best or you don't have much time for practice slow it down to 280 fps. And of course not everyone can get this fast without getting to light. It's a balancing act.

So I don’t think it’s fair to say a heavier arrow is less accurate. It’s the yardage estimation that lacks accuracy.

We misuse about our terms in archery. There's a difference between accuracy and precision - see below. Range error by definition is poor accuracy as it misses the intended mark. Precision is the ability to group well. You can definitely group well if you bow is setup well.

It seems illogical to me to up your weight just to put a head with the least structural integrity (mechanical), since we already agreed that that was more important than weight. And aren’t heads with wider cuts less accurate?

To be clear - I'm not really advocating for mechanicals. But logically it makes more sense than increasing your energy & momentum and then decreasing your cut size from the average hunter who doesn't have issues with penetration anyway. Again, we're limiting the speed limit of our diesel to the Tacoma. Also, there's plenty of mechanicals out there now with durability. IE Sevr and others. Sevr even passed the Ashby testing. A Sevr will cut more and fly better than a long fixed head while still penetrating a minimum of 7 inches into a cape buffalo and holding up. Not a concern durability wise. Mine didn't fare quite that well but penetrated 10" or so on a elk. I'll stick to fixed unless I bump up arrow weight and energy.

Wider cut heads can be less accurate if given than the equivalent surface area. But a 150 vented Magnus Black Hornet will fly better than their new Magnus 150 grain single bevel all day every day and cut much more. A vented Grim Reaper Micro Hades 3b 150 grain will absolutely fly better than a Tuffhead 3b 150 all day every day. Given the same tolerances in straightness then it's just surface area - put a bigger plane on the front and it won't fly as reliably. Add vents and it will fly better. Make the head shorter and it reduces the area and it will fly better. An Exodus Swept 125 will fly better than say a Stinger Killer Bee and Valkyrie will fly exponentially better than a Ranch Fairy 3 blade.

I can keep going if you like - but this is reality. Heavier arrows get there slower, give the animal much more time to react allowing them to move further and be accelerating away faster but will hit harder. A massive 3:1 or just long unvented broadhead will not fly as well in the heat of the moment as nearly any other design on the market. Personally, if I want to shoot 20 & in I'll just shoot trad equipment. Until I get much better at hunting, I'll stick to the compound to fill the freezer.