Critique my arrow build - Newbie

[Billy Goat]

Thanks! How is it used? Like galamb said with a 300 spine arrow and my components I would be at 85 pounds. What does that mean? What should I be at? How is that used?

So, spine was used to help with archer's paradox, that's the arrow bending around the riser, then correcting to going where you are looking. That's how older bows worked anyways. The riser of a longbow, and many older recurves wasn't cut past center so the arrow had to bend or flex around the riser, thus you needed a certain spine for your setup.


Now with modern compounds we don't need that, you basically just need one that isn't too weak so your broadheads will fly well.

 

[Hschweers]

So, spine was used to help with archer's paradox, that's the arrow bending around the riser, then correcting to going where you are looking. That's how older bows worked anyways. The riser of a longbow, and many older recurves wasn't cut past center so the arrow had to bend or flex around the riser, thus you needed a certain spine for your setup.


Now with modern compounds we don't need that, you basically just need one that isn't too weak so your broadheads will fly well.

But what is too weak/too strong? With static spine, there’s pretty charts on the back of every arrow box that tells you about what static spine you need. I can’t find anything that tells you what you want your dynamic spine to be (which I’m sure varies greatly person to person). According to Galamb, I had 85lbs. 85lbs vs my target what? Is that high? Is that low? What is my dynamic spine supposed to be?

 

[galamb]

Since I am still primarily a traditional shooter many of us still calculate the dynamic spine requirements of the bow and then pre-calculate what the dynamic spine of an arrow "would be" if we built it a certain way - tipped it with whatever grain head.

A 50 lb longbow drawn to 30" with a 12 strand string might be balanced with a 62 lb dynamic spine arrow.

So using a calculator you can "phantom build" a few arrows to see if what you are thinking will be close.

It is NOT an exact science but what it does do is saves you from buying 240's or 300's because you are trying to buy off some chart and instead the dynamic (output) of the bow would tell you that a 340 or 400 spine would work at a given length with a certain weight broadhead.

There was a time when sourcing arrows was a bit of a challenge - you had to look for an ad in the back of a magazine and make long distance phone calls (unless you had a bow shop within 100 miles). So when you couldn't just go to a mfg website or Amazon and order away we figured out "what we needed" as close as we could ahead of time.

And calculating dynamic spine went a long way to figure out what would likely "work from the start" and then only required fine tuning.

I still use it now with my longbow and recurve - if I want to shoot a 200 grain head because it catches my eye, then I can quickly calculate if my current arrows are "enough" or if they would have to lose some insert weight or be shorter by an inch or if they simply don't have enough spine.

Or conversely, I can build an arrow and the dynamic spine calculator will tell me whether it would be better tipped with a 150 grain head or a 100. It can save the "spend and test and scrap that idea" that can be present until you have figured out what works for you.

So maybe I'm just old

 

[Billy Goat]

But what is too weak/too strong? With static spine, there’s pretty charts on the back of every arrow box that tells you about what static spine you need. I can’t find anything that tells you what you want your dynamic spine to be (which I’m sure varies greatly person to person). According to Galamb, I had 85lbs. 85lbs vs my target what? Is that high? Is that low? What is my dynamic spine supposed to be?

Most all this spine stuff is just a guess. There's a lot that enters into it, like how much face pressure you have, how clean your release is. I don't mess in anyway with a dynamic spine, my opinion is it's mostly a WAG. You start with an arrow off a chart or a program that is going to have you in the ballpark. Then you shoot it and see. In my experience with compounds, for a hunting bow there's not really a too stiff. You know you have a weak shaft when you aren't getting a consistent result. The stuff about arrow impact and if it's a weak or a stiff arrow is mostly about single string bows, not compounds. When you can't get consistent impact points, turn your limbs down, when that fixes it you know it's a weak spine. Mostly it's about tuning the bow, it's a wide range that a modern compound can handle. Don't get wrapped up on trying to have something perfect according to a chart or program, err on the side of stiff, shoot it.

 

[5MilesBack]

Billy hit on most everything I would comment on, and then Mighty Mouse hit on the first thing that caught my eye........those outserts. I'm a big HIT insert fan and have been using them for the past 15 years in all my .204" ID arrows. Outserts........especially the aluminum ones will bend easily.

I'm also currently using the RIP TKO's in the .250 spine and I cut my arrows at 30" ctc, but my draw is almost 33". Also, you could easily shoot the 350's (spine wise) out of that bow even leaving them at 30".

 

[galamb]

Dynamic spine is "old" and less important today with the uber-fast set-up's.

If you are making 100 KE or better even if you are losing 10% efficiency so what, you still have "double the minimum required for every animal in North America"

But if you are using older slower gear or you simply want to wring every ounce of power from your set-up and translate that into the arrow then dynamic spine is important.

You can calculate the dynamic (force) that your bow is trying to impart on the arrow. The formula looks at a bunch of variables - draw weight at what draw length, your draw length, your (degree) of center shot (I'm tuned to a -0.08" centershot which helps if I shoot a little "stiff", so a hair right of center but moving it to 0.0 adds a couple pounds of power) and the list goes on - every little variable adds/subtracts from the power that will be applied to the arrow when you release.

Basically what you are trying to figure is what is the max power available from your bow that can be applied to the arrow (Dynamic power).

In the case of my rather light draw, rather slow bow, for me that is 65 lbs.

So since I can't make double the KE needed like the fast new bows and can't really afford to lose 10% of my efficiency (don't have any to spare) I build my arrows targeting a "dynamic spine rating" of 65 lbs plus/minus 2 lbs.

If I can build to that spec I can translate "as close as I can manage" to 100% of "available bow power" into the arrow making my set-up "as efficient as possible because I don't have power to spare".

Now, with a newer bow yes you can just look at the static chart, get an arrow off the shelf and you will get acceptable results if you use the arrow "as built" from the mfg.

You can even "dress it up a bit" - cooler fletch, maybe add a wrap and even if you added 10 or 15 grains you wouldn't notice any change.

But I don't consider "making it pretty" to be "building".

I can get acceptable results if I buy a stock arrow, cut it to size and reinstall the factory insert.

But if I change the nock, add a wrap, maybe add 50 grains up front and decide to leave it 1/2" longer because it just fits better with the broadhead I paired it with all of those "weaken the dynamic spine" possibly by as much as 10% which means my "minimally powerful enough for bear or moose" is now lacking a little.

So if I'm going to "build" (to whatever target purpose (deer arrow - moose arrow) and weight) - spend the money on the components and spend my time I am looking to improve the efficiency over what I can get "off the shelf" and I certainly don't want to build an arrow that will "waste" some of my limited power.

 

[Mighty Mouse]

I build my arrows targeting a "dynamic spine rating" of 65 lbs plus/minus 2 lbs.

Out of curiosity, what chart/calculator do you use to determine your dynamic spine rating? The only time I ever hear guys discuss dynamic spine in units of pounds, it's either in reference to the Stu Miller calculator on 3 Rivers Archery's website or to a wood arrow spine chart.

 

[galamb]

I use the 3 Rivers Calculator which has been updated with the majority of the carbon arrow offerings now.

It doesn't calculate the dynamic for other than trad bows but the arrow portion of the calculator has options for just about every variable you may want to add or change for an arrow.

I know the dynamic of my bows from years gone by (and don't really remember what calc I used to get "their number" so now I just use the arrow portion to build a "virtual arrow" and then tweak it until it looks good on paper - then build it, bare shaft tune it at 20 and 30, fletch it and tweak my sights (and usually only if I have gone lighter or heavier and need vertical, never horizontal, adjustment from there.

It works well "for me" and it's rare that I have to tear out components and replace them to get the arrows to fly right with the weight and distance I build them for.

 

[Hschweers]

Dynamic spine is "old" and less important today with the uber-fast set-up's.

If you are making 100 KE or better even if you are losing 10% efficiency so what, you still have "double the minimum required for every animal in North America"

But if you are using older slower gear or you simply want to wring every ounce of power from your set-up and translate that into the arrow then dynamic spine is important.

You can calculate the dynamic (force) that your bow is trying to impart on the arrow. The formula looks at a bunch of variables - draw weight at what draw length, your draw length, your (degree) of center shot (I'm tuned to a -0.08" centershot which helps if I shoot a little "stiff", so a hair right of center but moving it to 0.0 adds a couple pounds of power) and the list goes on - every little variable adds/subtracts from the power that will be applied to the arrow when you release.

Basically what you are trying to figure is what is the max power available from your bow that can be applied to the arrow (Dynamic power).

In the case of my rather light draw, rather slow bow, for me that is 65 lbs.

So since I can't make double the KE needed like the fast new bows and can't really afford to lose 10% of my efficiency (don't have any to spare) I build my arrows targeting a "dynamic spine rating" of 65 lbs plus/minus 2 lbs.

If I can build to that spec I can translate "as close as I can manage" to 100% of "available bow power" into the arrow making my set-up "as efficient as possible because I don't have power to spare".

Now, with a newer bow yes you can just look at the static chart, get an arrow off the shelf and you will get acceptable results if you use the arrow "as built" from the mfg.

You can even "dress it up a bit" - cooler fletch, maybe add a wrap and even if you added 10 or 15 grains you wouldn't notice any change.

But I don't consider "making it pretty" to be "building".

I can get acceptable results if I buy a stock arrow, cut it to size and reinstall the factory insert.

But if I change the nock, add a wrap, maybe add 50 grains up front and decide to leave it 1/2" longer because it just fits better with the broadhead I paired it with all of those "weaken the dynamic spine" possibly by as much as 10% which means my "minimally powerful enough for bear or moose" is now lacking a little.

So if I'm going to "build" (to whatever target purpose (deer arrow - moose arrow) and weight) - spend the money on the components and spend my time I am looking to improve the efficiency over what I can get "off the shelf" and I certainly don't want to build an arrow that will "waste" some of my limited power.

Thank you! This was some good information!

 

[Hschweers]

Alright, I've redone it to take into account that I don't need to worry as much about penetration, and should look for more speed with whitetail being the target.

Option 1: I already own these arrows. Bought them on the cheap cheap from the black ovis misfits. Only thing I need is heads
Gold Tip Hunter XT 340 (8.9gpi) cut to 30.5"
TAC Driver 2.75" 3 fletch (6.2gr/per)
Wrap 5gr
Nock 10.3gr
12.1gr GT insert

With a 100gr Exodus I'm at 417.5 TAW, 8.6% FOC, and 269 FPS. With a 125gr Exodus I'm at 442.5 TAW, 10.8% FOC, and 260 FPS.

Option 2: These are some I've concocted trying to get arrow weight down and speed up. I'd have to buy these.
Gold Tip Airstrike 340 (7.8gpi) cut to 29"
Q2i Fusion-X II 2.1" 3 fletch (5.8gr/per)
IW 25gr SS insert
Nock 10.3gr
No Wrap

With a 100gr Exodus I'm at 379 TAW, 11.7% FOC, and 282 FPS. With a 125gr Exodus I'm at 404 TAW, 13.9% FOC, and 274 FPS.

I have no problem forking over the money for the Airstrike build. However, I am currious if I were to go to 65 or 70lbs in the future, would I then need to go up to the 300 spine rendering these arrows useless? If that's the case, should I just go 300 spine now and be a little over spined at 60lbs?

 

[Mighty Mouse]

Option 2: These are some I've concocted trying to get arrow weight down and speed up. I'd have to buy these.
Gold Tip Airstrike 340 (7.8gpi) cut to 29"
Q2i Fusion-X II 2.1" 3 fletch (5.8gr/per)
IW 25gr SS insert
Nock 10.3gr
No Wrap

With a 100gr Exodus I'm at 379 TAW, 11.7% FOC, and 282 FPS. With a 125gr Exodus I'm at 404 TAW, 13.9% FOC, and 274 FPS.

I have no problem forking over the money for the Airstrike build. However, I am currious if I were to go to 65 or 70lbs in the future, would I then need to go up to the 300 spine rendering these arrows useless? If that's the case, should I just go 300 spine now and be a little over spined at 60lbs?

qSpine recommends 340 spine at 60 lbs and 300 spine at 70 lbs for the arrow length and component weights you listed. Keep in mind that spine charts/calculators just give recommended starting points (not set-in-stone requirements for good arrow flight) and that compound bows can shoot a fairly wide range of spines well. Arrows don't automatically become useless if you're one spine choice above or below the recommended "optimum." I think 300 or 340 would both work fine for you, but I would personally choose 300 if I thought I were likely to increase draw weight to 65+ lbs.

Common inputs: 315 fps IBO, 30" DL, 30" ATA, 6" BH, 75% LO, 29" C2C, 25 gr insert, 10.3 gr nock, 3 vanes at 5.8 gr ea

Output for 60# DW, 100 gr head:

Output for 70# DW, 125 gr head:

 

[galamb]

It looks like you could certainly turn it up to 65 no problem.

At 70 you would be right on the "static line" between a 350 and a 300.

But without opening the can of worms again, if the first arrow you mentioned back in your original post is flying in a totally acceptable fashion for you and you are mostly happy with it, then comparing that spine to a potential build on a 340 Airstrike, even dialing it up to 70 lbs would give you a similarly spined arrow (as far as "your bow" is concerned).

But the 300 would be "tougher" and allow you to increase front end weight either through inserts or broadhead weight if you ever wanted to take a dive down that rabbit hole for some future hunt.

 

[Hschweers]

qSpine recommends 340 spine at 60 lbs and 300 spine at 70 lbs for the arrow length and component weights you listed. Keep in mind that spine charts/calculators just give recommended starting points (not set-in-stone requirements for good arrow flight) and that compound bows can shoot a fairly wide range of spines well. Arrows don't automatically become useless if you're one spine choice above or below the recommended "optimum." I think 300 or 340 would both work fine for you, but I would personally choose 300 if I thought I were likely to increase draw weight to 65+ lbs.

Common inputs: 315 fps IBO, 30" DL, 30" ATA, 6" BH, 75% LO, 29" C2C, 25 gr insert, 10.3 gr nock, 3 vanes at 5.8 gr ea

Output for 60# DW, 100 gr head:
View attachment 400987
Output for 70# DW, 125 gr head:
View attachment 400986

Appreciate it! Honestly, if 60lbs was killing and not leaving anything to be desired, I likely won't increase my weight just to be macho (I get it, more speed, less time for reactions, blah blah. If it kills efficiently, I'm happy).

 

[Hschweers]

It looks like you could certainly turn it up to 65 no problem.

At 70 you would be right on the "static line" between a 350 and a 300.

But without opening the can of worms again, if the first arrow you mentioned back in your original post is flying in a totally acceptable fashion for you and you are mostly happy with it, then comparing that spine to a potential build on a 340 Airstrike, even dialing it up to 70 lbs would give you a similarly spined arrow (as far as "your bow" is concerned).

But the 300 would be "tougher" and allow you to increase front end weight either through inserts or broadhead weight if you ever wanted to take a dive down that rabbit hole for some future hunt.

I don't have the original arrow build I posted, I would've been buying those. I do have option 1 (GT Hunter XT) currently. Do you think getting 40 grains lighter for 15fps more warrants the ~$225 price tag of the Airstrike build?

 

[galamb]

There is nothing wrong with the hunters - decent utility hunting arrow - no, not fancy but doesn't drain the wallet either.

And 40 grains would be more like an 8 fps difference, not 15 and if you will be making anywhere in the 270-280 fps range you already have more speed then you honestly need.

When I use the (Voodoo ballistics calculator) the heavier build would see a 65" drop from aimpoint at 50 yards and 96" at 60 yards

The 40 grain lighter would be 61" of drop at 50 and 91" at 60.

At 30 yards the drop difference is within an inch.

And if the "how far it drops at distance" sounds surprising it's because what many think of as "flat shooting" is actually "dropping in from Many Feet above the target"

We are spoiled by thinking rifle where you you are 2" high at 100, on at 200 and a couple low at 300. But we are shooting twice the weight at 1/10th of the speed - flat is relative.

 

[Mighty Mouse]

I don't have the original arrow build I posted, I would've been buying those. I do have option 1 (GT Hunter XT) currently. Do you think getting 40 grains lighter for 15fps more warrants the ~$225 price tag of the Airstrike build?

If it were my money and I were wanting more speed, I'd keep shooting the GT Hunters and put that money toward a faster bow. IBO speeds on recent flagship bows are typically around 340 fps, which is going to shoot 20-25 fps faster than your current bow at whatever arrow weight you choose. Your current bow is perfectly capable of killing whatever you want to hunt (and will draw more smoothly than a faster bow), but if you're chasing speed I'd say put your money toward a faster bow rather than a lighter arrow.

 

[Billy Goat]

There is nothing wrong with the hunters - decent utility hunting arrow - no, not fancy but doesn't drain the wallet either.

And 40 grains would be more like an 8 fps difference, not 15 and if you will be making anywhere in the 270-280 fps range you already have more speed then you honestly need.

When I use the (Voodoo ballistics calculator) the heavier build would see a 65" drop from aimpoint at 50 yards and 96" at 60 yards

The 40 grain lighter would be 61" of drop at 50 and 91" at 60.

At 30 yards the drop difference is within an inch.

And if the "how far it drops at distance" sounds surprising it's because what many think of as "flat shooting" is actually "dropping in from Many Feet above the target"

We are spoiled by thinking rifle where you you are 2" high at 100, on at 200 and a couple low at 300. But we are shooting twice the weight at 1/10th of the speed - flat is relative.

Over lunch I was actually playing with 2 different spined arrows. Same arrows, same fletching, same front weight. 42 grains difference and 18 fps difference. 60#, 28.5 DL.

 

[Hschweers]

If it were my money and I were wanting more speed, I'd keep shooting the GT Hunters and put that money toward a faster bow. IBO speeds on recent flagship bows are typically around 340 fps, which is going to shoot 20-25 fps faster than your current bow at whatever arrow weight you choose. Your current bow is perfectly capable of killing whatever you want to hunt (and will draw more smoothly than a faster bow), but if you're chasing speed I'd say put your money toward a faster bow rather than a lighter arrow.

Between you and galamb, I think I’ll give the Hunters a shot. If I can’t get them to shoot, I’ll reconsider. Is there any way to (successfully) remove glued in inserts? Wouldn’t mind taking them out, sawing them down to 29”, and replacing with the 25gr IW inserts.

 

[Billy Goat]

Between you and galamb, I think I’ll give the Hunters a shot. If I can’t get them to shoot, I’ll reconsider. Is there any way to (successfully) remove glued in inserts? Wouldn’t mind taking them out, sawing them down to 29”, and replacing with the 25gr IW inserts.

If you are taking them out and cutting, I just heat a field point and pull them. Even epoxies soften up with heat, but they will pull some carbon too. If you are cutting 1.5 or so off, just heat them up, pull with pliers.

 

[galamb]

I shoot some "old" hunters that I use for target with my recurve - 5575's which are now the 400's and 7595's which are now the 340's - they are both built "heavy".

The 400's weigh 478 grains and the 340's are 545 grains (both cut at 30.5")

Chrono'd at 3' I'm getting 187 fps average for the 400's and 175 fps for the 340's - so 67 grains difference I'm seeing 12 fps which sounds pretty close to the 5 grains = 1 foot rule of thumb.

That's what I based my "closer to 8 fps" on.