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Arrow Ballistics Argument

This is a test conducted in order to consider the effect of weight vs. KE in regards to hunting arrows, and whether a heavier shaft truly had enough stopping power downrange to warrant usage. This test utilized the same fletchings, nocks, and field points (100 grains).

I did this test because A. I wanted new arrows and B. was tired of debates on AT that showed no data. Here we go :wink:

Empirically, the findings appear to conclusively favor a more common hunting weight of ~415 grains vs. a heavy-weight arrow ~515 grains for almost all game on the planet.

For this test I weighed two arrows I currently use in my hunting setup, both 300 spined Easton FMJ 5mm and Easton Axis 5mm. I found these good candidates because they are exactly 100 grains of difference at my 30" arrow length, and two common hunting arrows that are polarizing in their differences.

Test Results

Easton Axis 5mm
287 fps - 413 gr arrow (with drop differences in inches vs. heavy arrow)
drop at 30 - 21 5" higher POI vs. FMJ
40 - 37 9"
60 - 86 21"
70 - 121 28"

Easton FMJ 5mm
254 fps - 513 gr arrow (with percentage differences)
30 - 26 1.23% drop difference vs. Axis
40 -46 1.24%
60 - 107 1.24%
70 - 149 1.23%

Findings

at 70 yards: FMJ had 62 vs 61 (Axis) KE ft/lbs
at 70 yards: FMJ had 0.53157 vs. 0.47181 (Axis) slugs of momentum
(FMJ 1.63% more KE) at 70 yards
(FMJ 12.66% more momentum) at 70 yards
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at 70 yards: FMJ had a 1.1774% loss of KE and 1.0869% loss of momentum
at 70 yards: Axis had a 1.2295% loss of KE and 1.1138% loss of momentum
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Difference in KE loss - 4.4% more KE loss using Axis arrow
Difference in momentum loss - 2.4% more momentum loss using Axis arrow

Adding a silencing package to the string (additional 20 grains) only decreases speed by 6 fps, negligible in results. The difference in KE and momentum is negligible. Largest concern areas between the two test arrows include noise of shot and arrow drop. Considering a silencing package will drop DB rate on lighter arrows and retain almost exact trajectory, it is therefore advised to use lighter arrows. The speed and forgiveness in parabolic arc is much more effective to a hunters success rate vs. sheer momentum at 70 yards.

I shoot 515 grain arrows. 30 inches long. I will be switching to a lighter arrow this season after these findings. It is hard to ignore the nearly 2 foot drop difference at only 60 yards, and 3/4 foot drop at 40 yards. The difference in noise can easily be remedied.

Unless the world's toughest game (grizzly, cape buffalo, etc) are hunted, there is no need for the downrange Momentum gain by using a heavy arrow such as the Easton FMJ. I hunt these animals sparingly, and when I do all I need to do is switch out my sight and grab my heavy arrows. Since my bow is tuned correctly for all arrows, I do not need to retune.

FMJs are prone to bending, whole Axis have a reputation as one of the toughest carbon shafts on the planet. FMJs, however, are easier to pull from certain targets (high density foam).

WOULD YOU CHANGE YOUR ARROWS AFTER THIS STUDY?
 

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No I am probably gonna shoot Easton hexx/datorch around 508 grains. I don’t shoot over 40 yards for hunting situation so drop isn’t a bother to me and I use a range finder anyway so I’ll keep on keeping on. I like the 6mm shafts cause I can use a insert with a neck instead of a hit or outsert. It’s just easier, never had a problem with the hit inserts though.


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I use HIT inserts as well. I actually like them, I don't understand all the hate. I was given 6x Hexx and 3 shattered in the first shooting session (from hitting nocks) and that's when I got over them real fast.
 

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I don’t have a problem with the hits but like regular inserts. I have never busted a hexx, I pulled one out of a 2X4 when it blew through my target. I ain’t hating on axis(don’t like fmj, to easy to bend) I shot them for awhile and wanted to get higher foc and maintain a decent arrow.
 

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The Ranch Fairy
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Well, if your only concern is getting the arrow to hit the target, you win.
After impact at all ranges, is a completely different story.

Nice job shooting all those shots and keeping such tight records.
How many total shots did you take to get an average?

Yes, I would shoot the heavier arrow - to answer your question.
If you intend to go up to “the worlds most dangerous game” I would suggest adult arrows. 650-700 grains.
 

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put brass inserts in your axis to get to 450-475 and call it good. im not an fmj fan.

but .47 vs .53 momentum is a pretty big difference. your 30" draw will cover up a lighter arrows lackings for the most part.
 

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A Axis 5mm with a brass insert is hard to beat for hunting. It’s been my main hunting arrow ever since they came out. I have put hard telling how many of them thru animals. I haven’t ever had a probablem with a Axis arrow. I tried the FMJ’s but after shooting aluminum arrows for so many years before Carbon arrows come out. I just am not going to put up with bent aluminum anymore.
 

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Corripe Cervisiam
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OP, your data is wrong, leading you to a flawed conclusion.

Are you using a calculator vs actually shooting through a chrono? If you do have a chrono at 70- something fishy going on.

As arrow weight increases so does KE and Momentum, its physics. The software programs sometimes dont account for the fact that a heavier arrow absorbs more of a bows energy.
 

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As a white tail hunter, I value shot placement over penetration. Flat trajectory helps shot placement. I am 29” draw but shoot 27” axis 400 vs a longer 340.


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What are you hunting in Spain, and how long are your shots? The drop in trajectory is easily accounted for with a range finder, which is necessary if you are shooting at 60-70 yards (unless your first name is Levi) If you are shooting goats/deer you are fine with the light arrows, for boar or big animals I would go with the heavy arrows. What broad heads are you using? On a side note, how popular is bow hunting in Spain, and do you have archery shops that stock everything you need? Just wondering what the hunting/geography is like in Spain? Thanks
 

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OP, your data is wrong, leading you to a flawed conclusion.

Are you using a calculator vs actually shooting through a chrono? If you do have a chrono at 70- something fishy going on.

As arrow weight increases so does KE and Momentum, its physics. The software programs sometimes dont account for the fact that a heavier arrow absorbs more of a bows energy.
What am I missing?
His data indicates both more KE and more momentum for the heavier arrows, as well as less LOSS of those values at that distance from (I assume) point blank values compared to the lighter arrow.

(So if I'm reading it right, his data acknowledges superior energy transfer from bow to target with the heavier arrow, but his conclusion is that for him it's not enough to outweigh the trajectory superiority of the lighter one.)

Edited to add: Again, I'm assuming he took point-blank chrono readings and just neglected to mention them. I may be wrong though.

OP-please clarify!
 

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Corripe Cervisiam
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What am I missing?
His data indicates both more KE and more momentum for the heavier arrows, as well as less LOSS of those values at that distance from (I assume) point blank values compared to the lighter arrow.

(So if I'm reading it right, his data acknowledges superior energy transfer from bow to target with the heavier arrow, but his conclusion is that for him it's not enough to outweigh the trajectory superiority of the lighter one.)

Edited to add: Again, I'm assuming he took point-blank chrono readings and just neglected to mention them. I may be wrong though.

OP-please clarify!
Actually it was me that misinterpreted his study- my appologies OP
 

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Well, if your only concern is getting the arrow to hit the target, you win.
After impact at all ranges, is a completely different story.

Nice job shooting all those shots and keeping such tight records.
How many total shots did you take to get an average?

Yes, I would shoot the heavier arrow - to answer your question.
If you intend to go up to “the worlds most dangerous game” I would suggest adult arrows. 650-700 grains.
I shot 5 of each arrow, alternating between, using my sight that was setup for the axis. Im still going to use both, but axis for almost everything unless I need a reason to slide metal in ;). I do disagree on needing 700 grains. Im canadian and have shot grizzlies, moose, etc with the FMJ setup and had nothing but passthroughs. I have no desire to shoot a hippo or anything. 322IBO bow at 29" and 72 lbs.
 

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OP, your data is wrong, leading you to a flawed conclusion.

Are you using a calculator vs actually shooting through a chrono? If you do have a chrono at 70- something fishy going on.

As arrow weight increases so does KE and Momentum, its physics. The software programs sometimes dont account for the fact that a heavier arrow absorbs more of a bows energy.
I never calculated speed at 70 yards. I shot groups, and used calcs for computations.
 

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A Axis 5mm with a brass insert is hard to beat for hunting. It’s been my main hunting arrow ever since they came out. I have put hard telling how many of them thru animals. I haven’t ever had a probablem with a Axis arrow. I tried the FMJ’s but after shooting aluminum arrows for so many years before Carbon arrows come out. I just am not going to put up with bent aluminum anymore.
Me either. Its too expensive for what I consider to be a major defect. I shoot my FMJs nd think "ok, theres a chance that fkers bent now." ITs like having sex without a condom. Its just too risky!
 

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What are you hunting in Spain, and how long are your shots? The drop in trajectory is easily accounted for with a range finder, which is necessary if you are shooting at 60-70 yards (unless your first name is Levi) If you are shooting goats/deer you are fine with the light arrows, for boar or big animals I would go with the heavy arrows. What broad heads are you using? On a side note, how popular is bow hunting in Spain, and do you have archery shops that stock everything you need? Just wondering what the hunting/geography is like in Spain? Thanks
Honestly Spain is a pain in the ask. It is "popular" here but bows have a special legal status, so you need to be a member of a club to shoot, which of course carry fees of 200 euros or more. I live near Alcornocales park, which has some incredible hunting. The good news is the seasons for hunting here are REALLY long. As far as ger, there is a shop in Madrid (cerra and NockPoint) that are good, but easily 30% higher prices than the US. Also no returns, bad service, uncaring staff. Most archers here care about Olymic style shooting. You wont find many true hunters. Not the way we know them.

I shoot a ramcat on bigger game and hypodermic on anything smaller than big bears. I dont think you NEED a COC for deer. I do, however, not want to risk the chance of a mechanical not deploying on a grizzly at 40 yards.

Spain is mountain goats and fallow/red/roe deer. Some sheep are here but are too expensive for me. I do not use a rangefinder, I have an excellent system in place. I did my test to 70, but will not take a shot past fifty. Also, my yardage tapes are set to my paces, not exact yardages. For me its easier to gauge a length of my own step than a standard unit of measurement.
 

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What am I missing?
His data indicates both more KE and more momentum for the heavier arrows, as well as less LOSS of those values at that distance from (I assume) point blank values compared to the lighter arrow.

(So if I'm reading it right, his data acknowledges superior energy transfer from bow to target with the heavier arrow, but his conclusion is that for him it's not enough to outweigh the trajectory superiority of the lighter one.)

Edited to add: Again, I'm assuming he took point-blank chrono readings and just neglected to mention them. I may be wrong though.

OP-please clarify!
I took point blank chrono readings. EDIT: like 2 yards away. I consider that point blank though. Im not a damn scientist :darkbeer: Thanks for the backup! Also, all computations done at 70 yards except initial speed test. And yes, you have read my conclusions correctly. There is simply too much to gain from trajectory vs. a minimum gain in downrange (actually, long range) power.
 

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Yes, I prefer 5MM Axis. How did you come up with 413 grains for a 5MM Axis 300 spine (10.7 gpi.) 30" long with 100 grain point. A 5MM Axis 300 spine with 100 grain tip that is...30" long from the valley of the nock to the end of the shaft...will weigh around 459.9 grains. With 2" blazers vanes.

29 5/8" x 10.7 = 316.9 grains
tip = 100 grains
Insert = 16 grains
Nock = 9 grains
Vanes = 18 grains
Total = 459.9 grains
 
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