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Discussion Starter · #1 ·
I shoot a switchback with a 26.5 draw, set at 65 lbs, 25 inch carbon express maxima 250 arrows with 85 grain tips. The arrow alone weighs 7.3 grains per inch. The matthews book says that you should shoot an arrow that weighs 5 grains of arrow per pound, or you are simply dry firing your bow. I don't have a scale to weigh my arrows, does anyone know if this is an ok setup??? An archery shop told me that's what i needed??
 

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Discussion Starter · #4 ·
I am using speed nocks and vanes that came on arrows, no wraps. I still believe he set me up with too light of an arrow, i just tried to paper tune and got a left tear which from what i have read determines that i need a stiffer spline arrow.
 

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A left tear can mean several things, only one of which is an indication fro a stiffer shaft. Your arrow is too light. Biggest thing about shooting the toothpicks is when the bow FUBARS the manufacturer may not honor the warranty if you are under the 5 grain per pound limitation. I guess I am a little old school as I shoot serious logs from mine.
 

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Just be careful with an arrow that short, I mean don't accidently get an arrow with a real stiff spine.
 

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Don't confuse arrow weight and arrow spine. While stiffer spine arrows are normally heavier, there is no direct correlation between the two.

I would get a couple of those arrows weighed either by a pro shop or someone with a grain scale, such as a gun powder scale. If the shaft alone is 7.3 gpi, then it is 182.5 grains. I believe the lightest nock CE makes is 7 grains, the lightest insert is 12. 3 - 4" vanes are about 25 grains. Add your 85 grain tip and I come up with 311.5 grains, which is about 14 grains light. You can either back off your pull to 62# or consider a 100 grain point. Read the rest before deciding.

I checked your bow and shaft specs at Carbon Express' website and the spine is coming out almost perfect. Remember that short shafts have more apparent spine than longer shafts, so shorter shaft arrows must be a lighter spine to achieve the same spine affect. If you change to a 100 grain head you are still 2 draw weight categories below having to jump up to the next higher spine CE shaft. So I would suggest that your shaft is stiff enough.

Since you didn't mention much about the tuning you have tried or not tried, I would suggest checking for any rest contact first, then adjusting your rest to get rid of the left tear, using the 100 grain point. If you can accomplish that without moving the rest more than 1/16" or so from the ideal 13/16" center shot distance, the shaft is the right spine. Also be sure you are not torqueing the bow. I have always maintained, along with many pro coaches, that if the draw length is correct but the string is still slapping your arm on most modern compounds, with the exception of the short brace height speed bows, you are most likely having form problems. These form problems with obviously cause left/right tears.

So I guess, in summary, you should check vane clearance, switch to 100 grain head/points, and tune. A good tuning guide is the Easton guide you can download from their site. http://www.eastonarchery.com
 

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If your arrow weighs a little less than 325 it shouldn't be a big deal. You shooting a arrow that weighs 311grs at your draw length will have less ill effects on your bow than somebody shooting a 325 at 30" draw.
 

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olehemlock said:
If your arrow weighs a little less than 325 it shouldn't be a big deal. You shooting a arrow that weighs 311grs at your draw length will have less ill effects on your bow than somebody shooting a 325 at 30" draw.
Right on the money. The 5 grain per pound thing is not an absolute and it is recommended on 30" draw bows, which produce considerably more energy than your 26.5" draw. Look at the force draw curves of both bows -- the area under the curve is the energy. You have considerably less thus you can shoot a lighter arrow.

Theorhetically, you can shoot as light of an arrow that gets your speed to the IBO speed of the bow.

I don't think the dynamic spine of your arrow is weak, especially due to the light tip and short arrow length and also assuming heavy 4" vanes on the back (all these things make an arrow's dynamic spine reaction act 'stiff').
 

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Discussion Starter · #12 ·
Thanks

I just got back from the archery shop where i bought the bow, my idler pulley was leaning, now i'm shooting bullet holes, and he showed me an amo chart for arrow weight, and the arrow setup is fine. Thanks for all the comments.
 
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