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Discussion Starter #1
Need some education. How do I go about selecting the appropriate spines arrow and target tip combination? My draw length is 27.5 and draw weight is 61 pounds. Thanks in advance


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Need a little more info for somebody to make a fully accurate recommendation. What's IBO rating on your bow? Are you wanting arrows as short as possible or sticking out past end of riser? For target or hunting or best of both combo? The arrow chart by previous poster is a decent "starting point". I used fixed broadheads and almost always find the charts to be about one spine choice too weak. I suspect you will end up with a 350 spine for optimum performance...maybe 400 if you want to keep arrow short and/or aren't looking for lot of FOC.
 

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There are basically 2 ways, arrow spine chart and the computer programs. I like the Gold tip spine selection chart because it has 3 point weights listed and you can easily see what arrow length and point weight do to dynamic spine. Dynamic spine is the actual flex you get with a cut arrow and total point/insert weight. Its the shaft length, not your draw length, but draw length does impact the dynamic spine because you are exerting force on the shaft for a longer time. Static spine is what is printed on the shaft/advertised is is the amount a shaft flexes in thousandths of an inch when supported at a 28" interval with a 2 pound weight hanging in the middle. i.e. a 350 spine shaft bends .350" with the weight hanging on it. You will hear about another spine of an arrow mentioned, thats when you rotate a shaft with the weight hanging on it, there will usually be a weak place and or a stiff place. more advanced archers "index" their shafts (sometimes called nock tuning) so that all their arrows react the same.
Looking at the GT chart, if you cut your shafts at 28" (a conservative length for a broad head) and a 100 grain point, they recommend a 60-64 pound range (a high IBO speed bow would be 60, and a slower bow @64
with a 125 grain point is would be 5-59 pounds
If you cut your arrows shorter (If you have a full containment rest) you can go up @3 pounds for every inch you cut off.
Hope this helps.
 

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Discussion Starter #5
Need a little more info for somebody to make a fully accurate recommendation. What's IBO rating on your bow? Are you wanting arrows as short as possible or sticking out past end of riser? For target or hunting or best of both combo? The arrow chart by previous poster is a decent "starting point". I used fixed broadheads and almost always find the charts to be about one spine choice too weak. I suspect you will end up with a 350 spine for optimum performance...maybe 400 if you want to keep arrow short and/or aren't looking for lot of FOC.
My bow is the Hoyt RX1 rated at 340 (?). Utility, best of both worlds as i’m just picked up this new archery addiction and trying to feel my may into my comfort zone. A local shop has sold me both axis 340 and 400 with both 125, 100 and 80(?) tips. I just don’t know what is what and i don’t like knowing my equipment.


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What's the length of the arrows you have from the shop? Have you/shop tuned the bow? If so, does one of the arrows group better than the other? One of the two Axis should shoot pretty good for you.

Being new to the sport, I'd encourage you to make sure your form is pretty solid and repeatable. Also make sure the bow is tuned well and work with the two different arrows you have now to achieve tighter groups. I expect the 340s with the 125 or 100 grain tip will be your best bet. The 400s with the 100 grain might do it. If you intend to hunt, I'd stay away from those 85 grain tips.

If you really want to fine-tune arrows, check into the OT2 archery software program. That can help you build an arrow with optimum spine and the Front Of Center you want to get out of it.
 

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You need a 340 spine especially if shooting a 125 grain tip. You might be able to get away with a 400 if you cut those arrows to 27 inches and shoot a 100 grain tip. Stay away from 85 grain anything.
 

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x2 on the OT2 software by Pinwheel
 
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