X7 and X10's -same group different results

mbaker74

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I have been shooting 550 spine x10's for 2 seasons now and they tune perfectly for my uukha box, 29.5" arrow, 41b OTF. From the Easton chart they are T7 and should be slightly soft, but aren't.

I wanted some aluminiums for indoors as not wanting to damage x10's indoors. Spine shoice seemed very simple to me, pick the same spine group as the x10's..... so I bought a set of X7's in 2114 size, which should give a spine of 0.51" compared to my x10's of 0.55"

i fletched the x7's with 3" AAE vanes, and fitted Easton superlite nocks and nibb points (78) grains.

I set them up as normal, centre shot with the point just to the left of the string, sight pin centred over the shaft, then changed button tension to move the fletched group into the centre.

tried some bare shaft testing tonight, and the bare shafts are level with fletched, but off a Portsmouth target to the left at 20yds, indicating they are way way too stiff!!!!

also, i am getting vane contact on the shelf of the riser, leaving a red streak of plastic.

So, has anyone else had such different results with arrows in the same T group?
how much difference would changing from 78grain nib points to 100 grain bullet points make to the tune,
and would a stiff arrow result in vane contact on the riser shelf? I was expecting to have to alter the nock height, but the bare shaft shows it's fine.....
 

iandall

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In short, yes.

I found X7s with nibb points difficult to bareshaft tune. If you take a bareshaft with center of gravity not far enough forward, they are unstable - the aerodynamic forces with a slight deflection of the arrow are in a direction to increase the deflection. I was able to get them tuned, but it was s hit or miss affair (this was with 2014s) then I stepped up to 2212s with an increased point weight (PDP points, 150grain or maybe even 180grain, I don't recall). Anyway, the stiffer arrows with heavier points fly much better. Bareshaft tuning is just like you would expect.

I'd try increasing the weight of your points. One way to do that with nibb point is to add solder. Use rosin core solder, cut off bits until you get the desired weight, place them inside the aluminium shank then hold the whole thing point down over a flame until the solder melts. The solder won't take to the aluminium shank, but the actual point is nickel plated steel and solder takes to that well.
 

Timid Toad

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Eradicate contact with your bow first. That will be absorbing energy so your arrows are showing stiff. Try moving your nocking point. Might seem counter intuitive, but you have to get rid of the fletchings hitting the shelf before you can make any other judgement.
 

Rik

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Just an observation: a spine group on the charts is quite a big range.
So far as I know there's no guarantee that two shafts within the same group will match one particular setup, especially if one of them is a little edgy for it.

But on this issue;
Contact in particular falls into the "fix it first" category of problems because it can lead to false conclusions on the rest of it. But it's not so easy to draw conclusions from the contact other than "something is wrong". I could make a case for it being a weak indication (shaft not bending quickly enough to clear the bow) or a stiff one (shaft not bending enough to clear the bow or so quickly it bends back in). If the contact is at the belly of the bow, I'd probably assume "weak" as a starting point though.
 

mbaker74

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Thanks all,
the contact is on the horizontal part of the riser below the arrow rest. It looks like the bottom fletching nearest the bow is just running the bottom edge along the riser shelf. When you look along the arrow from the back, it does look like this fletching will contact the riser but I have no idea how to stop it, the nocking point is already about 6mm above square, and the bare shafts land level with the fletched.
My only thought now is to get some heavier points in and see adjusting the effective arrow spine makes the fletchings clear the riser. If I raise the nocking point any more, im going to be shooting downhill I think....
 

Timid Toad

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Very long, low profile fletchings might do the trick. If you're up for some fun, and have spares, take a pair of scissors to 3 of your bottom fletchings. slice about half off the height. Shoot. Obviously if this produces different groups, try chopping height off all the fletchings on the three and shoot again. By the way, what rest are you using?
 

mbaker74

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AAE vanes are only 0.5" high already.... Shibuya rest, adjusted so the arm does not protrude past the edge of the arrow when viewed from above.
 

Timid Toad

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Ok, next suggestion(s): move your arrow rest *out* a little - just in case the back end of the arrow is dropping as the rest collapses. If it takes a little longer to fold in because it has further to travel... just an experiment, not a final position. Secondly, wind your button up to full stiffness while still having full travel. I wouldn't shoot you bare shafts like this, but I'm looking to see if you can eliminate the shelf-strike.
 

Whitehart

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Not much help now but 2014's would have been my first choice with 550 at your D/L
So 2114 and heavier points and 4" feathers for indoors is the way I would go.
Tophat do a B/O point 165-210 if you want an off the shelf solution.
 

mbaker74

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From the Easton chart, 2014's should be an entire group too soft, so actually yes probably bob on.
Why would you have chosen them against what the chart says?
 

geoffretired

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When you look along the arrow from the back, it does look like this fletching will contact the riser but I have no idea how to stop i
If, instead of looking at the arrow from the back, you put the back of the arrow on the rest and note how high the fletchings are above the shelf, you will get a better idea of clearance or no clearance.
 

QuiveringFool

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I had a similar issue moving from x10s to X7s (though mine were 650 x10s and 1914 X7s - same Easton group). X7 bare shaft way waaay left. Messed about with draw weight to try and bring it closer to fetched group but results were unsatisfactory. Finally ended up making changes to the centershot (angle of bare shaft was the give away) to bring tip of point much closer to I line with string. Results now spot on and arrow flight is good. Might be worth a look anyways.

Sent from my SM-N950F using Tapatalk
 

nbuuifx

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I have tried X7 2114 arrows this season, like you they matched my arrows from the Easton Chart (I shot ACC arrows outdoors though)

I shoot a similar poundage to you and a very similar length of arrow.

I found exactly the same as you, that they went off to the left.

I ended up increasing the weight of the points to 130gn which worked in quite nicely, but then I cut them down to a better length (they were 31" or so) and the bareshaft now lands slightly left of the fletched group. On a Portsmouth face the bareshaft is now 9o'clock blue.

I've been quite happy with the setup though and I'm getting my highest ever scores and I'm consistently getting around the same point, 560s to 570s. Which is a good improvement on my ACC scores.

Maybe a little bit of final tuning could get me a couple of extra points but I'm worried about changing anything now in case I make it worse!


Just as a point to note, with my current setup the fletchings are all left of the point, on the bareshaft, the nock is right of the point. Not the tidiest looking result, but it does stop me hitting the nocks!


Forgot to say, I used solder to increase the weight. Works a treat and great for experimenting as you can heat it up and pour it out again if it doesn't work.

Also I used 4" Impulse vanes, they are 0.3" tall and don't contact the riser at all.
 
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