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Discussion Starter #1
Hey guys,

I wanted to check you you guys and see if you could help me check the proper spine of my arrows. I switched from a 72lb draw bow to a 62lb draw. My DL is 29" and my arrow length is 28". I shoot 100 grain tips. My bow is a single cam bow. I am currently shooting beman ics 400's at 285 fps. Does this spine sound right? The only reason I ask is I was shooting the same arrow off of my 72lb bow as well but kept them the same based on advise from the shop where I bought the bow. Should dropping 10lbs in DW change the spine of the arrow? It paper tunes great with the 400's but I think I am seeing a slight bit of arrow wobble when it gets about 20 yards down range. What do you guys think?

To recap:
Beman ICS hunters
Single cam bow
arrow length - 28"
draw length - 29"
Draw weight - 62lbs
Tip weight - 100 gr
 

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at 62# should be right/ I shoot same #'s and /works for me
 

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yea at 29 i agree w/flair
 

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try 85 gr tip and see if that improves arrow flight.
What bow is it?
400 spine at 72 # (if that was your original set-up) I think would be too weak. 340-300 at the dl and dw.
62# 340-400 depending on cams, length, etc.
I tend toward a stiffer spine, but that is just my preference.
How does it group?
 

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First off there is a lack of information to give a good answer too!

Need to know the following to give a good answer:

Bow make and model
Weight of stuff on the string(peep/loop, kisser(if present), silencers/"speed nocks")
Fletching type
Intended use of the setup(hunting, tournament or both)

In answer to the last question in your post, changing the draw weight does not change the spine of the arrow. Arrow spine remains constant, what is actually changing is the dynamic spine of the entire setup.

By changing the DW, you will either stiffen or weaken the dynamic spine, which could in turn mean a necessary change in arrow spine to maintain dynamic/static spine match.

Not all single cam bows will require the same static spine to match the dynamic spine. The reason is that each cam style(determined by IBO rated speed) is different, as well as how the archer has the bow setup.

Go to www.pinwheelsoftware.com and check out Software for Archers. Using this program you will see how well or not so well your chosen arrow will match to your setup dynamics.
 

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Discussion Starter #7
First off there is a lack of information to give a good answer too!

Need to know the following to give a good answer:

Bow make and model
Weight of stuff on the string(peep/loop, kisser(if present), silencers/"speed nocks")
Fletching type
Intended use of the setup(hunting, tournament or both)

In answer to the last question in your post, changing the draw weight does not change the spine of the arrow. Arrow spine remains constant, what is actually changing is the dynamic spine of the entire setup.

By changing the DW, you will either stiffen or weaken the dynamic spine, which could in turn mean a necessary change in arrow spine to maintain dynamic/static spine match.

Not all single cam bows will require the same static spine to match the dynamic spine. The reason is that each cam style(determined by IBO rated speed) is different, as well as how the archer has the bow setup.

Go to www.pinwheelsoftware.com and check out Software for Archers. Using this program you will see how well or not so well your chosen arrow will match to your setup dynamics.
OK...now I'm super confoosed. lol....My bow is a Parker Ambusher. The only thing on my string is a d-loop and G5 meta peep. My vanes are 2" blazers. This is a hunting bow. The bow ibo's at 310 but I only get between 280 and 285 (archery guy at the shop said their chrono is showing 6 or 8 fps slow).
 

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Discussion Starter #8
try 85 gr tip and see if that improves arrow flight.
What bow is it?
400 spine at 72 # (if that was your original set-up) I think would be too weak. 340-300 at the dl and dw.
62# 340-400 depending on cams, length, etc.
I tend toward a stiffer spine, but that is just my preference.
How does it group?
I recon it groups alright. But still, I swear I see a little wobble once the arrow is about 20 yards down range. Like I said, it paper tunes perfect. I don't really get into the walkback tune thing but there is no horizontal movement out to 50 yards. I don't have a pin past that.

 

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If you are getting between 280-285 with the beeman ics @ 62#, that is blistering fast! That would be about right for 70 lbs.
The 400's should be [email protected] 28".
 

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The little wobble at 20 yards might be from the white fletching causing an optical illusion as it spins. Since the arrows are traveling slower at the new 62# dw, you are able to pick up on the spin a bit better visually.
 

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Discussion Starter #11
The little wobble at 20 yards might be from the white fletching causing an optical illusion as it spins. Since the arrows are traveling slower at the new 62# dw, you are able to pick up on the spin a bit better visually.
Good point. I hadn't thought of that.

If you are getting between 280-285 with the beeman ics @ 62#, that is blistering fast! That would be about right for 70 lbs.
The 400's should be [email protected] 28".
Are these slow arrows? Still seems slow compared to some of the hoyts and pse's at the range.
 

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OK...now I'm super confoosed. lol....My bow is a Parker Ambusher. The only thing on my string is a d-loop and G5 meta peep. My vanes are 2" blazers. This is a hunting bow. The bow ibo's at 310 but I only get between 280 and 285 (archery guy at the shop said their chrono is showing 6 or 8 fps slow).
Not sure how I confused you, but if you have any questions feel free to pm me or email me at [email protected]

The ICS Hunter 400 was underspined for your 72# bow, but are correctly matched on your current bow, no need to change anything. The percieved wobble you are seeing is perfectly normal for an arrow. What you are actually seeing(If you are shooting correct form; however, you should not be seeing this, as you are peeking if you are) is the spinning action of the arrow from the fletching stabilizing the arrow in flight. As for the 280 fps, you are right where you should be for this setup if not actually 3 fps faster than I calculate you at(FYI - the Parker Ambusher is IBO rated at 320 fps)
 

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Discussion Starter #13
Not sure how I confused you, but if you have any questions feel free to pm me or email me at [email protected]

The ICS Hunter 400 was underspined for your 72# bow, but are correctly matched on your current bow, no need to change anything. The percieved wobble you are seeing is perfectly normal for an arrow. What you are actually seeing(If you are shooting correct form; however, you should not be seeing this, as you are peeking if you are) is the spinning action of the arrow from the fletching stabilizing the arrow in flight. As for the 280 fps, you are right where you should be for this setup if not actually 3 fps faster than I calculate you at(FYI - the Parker Ambusher is IBO rated at 320 fps)
Cool. Thanks for the help! I just didn't want to go purchase a bunch of arrows on bad advise from where I get my arrows. It happens from time to time.
 
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