Another underspined n00b

[gburk]

Hey all
New archer here, I’ve only been shooting seriously for a few months. Results have been decent so far but I feel like I have a long ways to go still. Bought a secondhand bow with some arrows and tightened down the limbs all the way.
The other day I had a serious flier (like 10” off at 30yds from what felt like a clean release) and prior to that had always noticed a significant whip in arrow travel. POI was generally predictable (operator error aside) but the flight didn’t seem right to me. I asked the local shop about it but they didn’t point out the obvious which I will relate forthwith:
70# Hoyt faktor turbo
29.5” draw
29” axis 5mm 340 spine
I think I calculated with the field points and inserts I’m shooting it’s around 490gr or so

Based on all the tables I’ve looked at I’m significantly underspined.

Searching the archives this seems like a common issue. My thought is to shorten to like a 28” arrow and 260 spine and try out some higher foc setups using Valkyries or iron will broadheads.

Does that make sense or are there any other recommendations from the gurus?

Also would you recommend the black ovis custom online builds?

Thanks!!

 

[Turkeygetpwnd38]

Without knowing exact setup you are looking to get into (FOC wise), 260 would put you just as much overspined as you are under now. I’d shoot Axis 300s at minimum 29”, definitely wouldn’t shorten your arrows to 28 if you are a 29.5 draw, I don’t know your exact set up but seems to be cutting it close. You can do a quick google of pictures/videos of people shooting arrows that end up being a bit to short... Axis 300, HIT 50grain insert, 100 grain head, should put you about right. If need a little more spine can always add weight to the back with illuminated nocks.
Just a note, I would stay away from super extreme FOC set ups. Some is good but to much is going to give you tuning nightmares and being a novice, you are going to spend a lot of money and end up frustrated.

 

[WYCFM1]

28” 300 spine axis 75g insert 100g head. Standard x nock will suffice. Then get your arrows custom cut to the straightest possible shaft by spinning them. You will never give a shaft justice it deserves if your Hoyt is not tuned well. Also if it’s not tuned to how you hold/torque your bow. Minimal cam leans means less nock travel in the power stroke of the string. which means arrow spine becomes more forgiving. Work on your form to help your arrows come off the rest straighter. You put your form together with a good straight power stroking string straight down the center shot of your rest and you’ve made it to the next level. If you have the will to learn bow tuning you can tune your own how much better than MOST shops. Not all shops but most. Good luck.


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[Topo_trekker]

First I would say make sure your d loop height and center shot is right. When you increased to 70 it changed it.

Sure you could do that...but..260 with a ton of foc is on the extreme side of things. With your setup you will be shooting arrows less than 250fps and gonna have to further tinker with your bow. Most will recommend against this.

300 spine would put you in the sweet spot.

A couple recommendations, wouldn’t say I’m a guru, but things I’ve seen over the years that make a difference with fixed blades are making sure to have your arrow cut no more than about a inch out from your rest. Also get a fletching jig and throw a 4 fletch on with a 2-3 degree helical. Just make sure everything spines out weight wise on both ends and you’ll be gold on the arrow setup.




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[gburk]

Without knowing exact setup you are looking to get into (FOC wise), 260 would put you just as much overspined as you are under now. I’d shoot Axis 300s at minimum 29”, definitely wouldn’t shorten your arrows to 28 if you are a 29.5 draw, I don’t know your exact set up but seems to be cutting it close. You can do a quick google of pictures/videos of people shooting arrows that end up being a bit to short... Axis 300, HIT 50grain insert, 100 grain head, should put you about right. If need a little more spine can always add weight to the back with illuminated nocks.
Just a note, I would stay away from super extreme FOC set ups. Some is good but to much is going to give you tuning nightmares and being a novice, you are going to spend a lot of money and end up frustrated.

Got it, I’ll double check the minimum length, I thought 28 would be fine but maybe not. Thanks for your help.

 

[Billy Goat]

Why not turn the limb bolts back down and shoot it how it was setup?

If you are new to archery I think you would be better to shoot lighter poundage and be able to focus on form. You will develop bad habits with heavy draw weight early on.

 

[gburk]

28” 300 spine axis 75g insert 100g head. Standard x nock will suffice. Then get your arrows custom cut to the straightest possible shaft by spinning them. You will never give a shaft justice it deserves if your Hoyt is not tuned well. Also if it’s not tuned to how you hold/torque your bow. Minimal cam leans means less nock travel in the power stroke of the string. which means arrow spine becomes more forgiving. Work on your form to help your arrows come off the rest straighter. You put your form together with a good straight power stroking string straight down the center shot of your rest and you’ve made it to the next level. If you have the will to learn bow tuning you can tune your own how much better than MOST shops. Not all shops but most. Good luck.


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Sounds like another vote for 300 spine vs 260, plus justification to buy a bow press I will pass along to the wife. Needed that, thanks!

 

[gburk]

First I would say make sure your d loop height and center shot is right. When you increased to 70 it changed it.

Sure you could do that...but..260 with a ton of foc is on the extreme side of things. With your setup you will be shooting arrows less than 250fps and gonna have to further tinker with your bow. Most will recommend against this.

300 spine would put you in the sweet spot.

A couple recommendations, wouldn’t say I’m a guru, but things I’ve seen over the years that make a difference with fixed blades are making sure to have your arrow cut no more than about a inch out from your rest. Also get a fletching jig and throw a 4 fletch on with a 2-3 degree helical. Just make sure everything spines out weight wise on both ends and you’ll be gold on the arrow setup.




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Good thoughts, I certainly don’t want to try to tune on a steep, unstable part of the curve. 300 spine with moderate FOC it is, then.
You’re saying keep the arrow as short as practical / safe so as to not overwork the spine, if I understand correctly. Hadn’t considered the fletchings variable either.
Thanks

 

[Brendan]

Your specs are almost identical to mine.

I run a 300 Axis cut to 27.5/28" carbon to carbon at 29.5" draw and have gone as short as 27".

I run a total of 175 grains up front between insert and broadhead.

Running the rest back almost to the tek riser works well for tuning on all my Hoyts and allows the shorter arrow.

 

[gburk]

Why not turn the limb bolts back down and shoot it how it was setup?

If you are new to archery I think you would be better to shoot lighter poundage and be able to focus on form. You will develop bad habits with heavy draw weight early on.

There's a question worth asking any red blooded american male- do you really need to bottom out your bow? haha In fairness, regardless of poundage adjustments I'm due for a fresh dozen arrows and plan to cut these 340's down for one of my kids' bows.

It's probably worth it to turn the limbs down at least temporarily just to see how the arrow flight differs, probably can learn something that way. Also would be curious of any form differences due to poundage, I would like to get some video of that, especially after 30s, 60s of hold... I'll try it, thanks.

 

[gburk]

Your specs are almost identical to mine.

I run a 300 Axis cut to 27.5/28" carbon to carbon at 29.5" draw and have gone as short as 27".

I run a total of 175 grains up front between insert and broadhead.

Running the rest back almost to the tek riser works well for tuning on all my Hoyts and allows the shorter arrow.

ah, I see that my rest is in fact slid all the way to the back of its 3/4" or so of travel. Good to know!

 

[Beendare]

GBurk- you are getting some good advice, a couple of general comments;

You never want to be underspined with a hunting arrow [with BH]

A guy with perfect form...AND a perfectly tuned bow can shoot a underspined arrow and get away with it- mostly. So that hints at a couple of things.....

If you think you are underspined, you CAN drop the weight of your bow and shoot until you get good arrow flight. This is a good diagnostic for spine issues....but of course tuning has to be there.

Its a worthy endeavor to learn bow tuning...pays big dividends

...

 

[gretch6364]

For the spine experts...

28.5" draw (bow might measure 28.75" 29" max., 71.8lbs, 6" Brace Height - Black Eagle Rampage, 250 spine, 100g BH, 100g FOCOS outsert system, 4 AAE Max Stealth Vanes, 10g nock - 540g total.

Is that a proper spine? I went one stiffer due to the heavier weight up front. Should be approximately 12.5% FOC.

Thanks

 

[Brendan]

For the spine experts...

28.5" draw (bow might measure 28.75" 29" max., 71.8lbs, 6" Brace Height - Black Eagle Rampage, 250 spine, 100g BH, 100g FOCOS outsert system, 4 AAE Max Stealth Vanes, 10g nock - 540g total.

Is that a proper spine? I went one stiffer due to the heavier weight up front. Should be approximately 12.5% FOC.

Thanks

Depends on arrow length, Bow IBO rating. You could probably run 300 spine, but 250 is safely stiff.

 

[gretch6364]

My IBO rating is 343....bow is probably in actuality doing 335-340. So 257-260 FPS at 540g.

Arrow length is probably going to be 28"...the 540g is at 28". Arrow is 10.7g per inch.

It seems like the spine charts don't account for more FOC from something like a 100g insert/outsert system.

 

[gburk]

GBurk- you are getting some good advice, a couple of general comments;

You never want to be underspined with a hunting arrow [with BH]

A guy with perfect form...AND a perfectly tuned bow can shoot a underspined arrow and get away with it- mostly. So that hints at a couple of things.....

If you think you are underspined, you CAN drop the weight of your bow and shoot until you get good arrow flight. This is a good diagnostic for spine issues....but of course tuning has to be there.

Its a worthy endeavor to learn bow tuning...pays big dividends

...

So the impact of the BH on an underspined arrow is primarily aerodynamic, during the time the arrow recovers from launch, is that right? Assuming consistent weight is maintained (TP<->BH) that's all i can figure.

Are we talking about "paper tuning" or is there more to it than that.

THANKS

 

[Brendan]

My IBO rating is 343....bow is probably in actuality doing 335-340. So 257-260 FPS at 540g.

Arrow length is probably going to be 28"...the 540g is at 28". Arrow is 10.7g per inch.

It seems like the spine charts don't account for more FOC from something like a 100g insert/outsert system.

You're starting to trend a little weaker than ideal with 300 spine. 250 is probably the right choice.

 

[Brendan]

So the impact of the BH on an underspined arrow is primarily aerodynamic, during the time the arrow recovers from launch, is that right? Assuming consistent weight is maintained (TP<->BH) that's all i can figure.

Are we talking about "paper tuning" or is there more to it than that.

Keep it simple. Start with the correct spine, then broadhead tune your bow.

Yes, you're correct that broadheads show error different from field points because of aerodynamics: you're putting a big sail on the front of an arrow, and if it isn't flying perfectly true it catches air and sends the arrow off target. Add too weak a dynamic spine (too much arrow flex) and you're asking for problems.

 

[Topo_trekker]

Good thoughts, I certainly don’t want to try to tune on a steep, unstable part of the curve. 300 spine with moderate FOC it is, then.
You’re saying keep the arrow as short as practical / safe so as to not overwork the spine, if I understand correctly. Hadn’t considered the fletchings variable either.
Thanks

Yes it’s about spine and safety but if your arrow is to long, generally more than inch out past the rest(past where insert sits inside shaft), it will start to magnify form inconsistencies and groups will open up. The arrow flexes the least on release right where insert sits inside shaft, that’s the sweet spot for arrow length.


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[gretch6364]

You're starting to trend a little weaker than ideal with 300 spine. 250 is probably the right choice.

Thank you. Yes, I was planning on 250.