Spining arrows for TXS

[Andyakashrek]

I have a pair of TXS's #38 and a set of KAP challenger carbons #36, both 68", so according to Easton they should use the same arrow spine. I use 2012 X7's and 3-04 ACC's at 28", T5 IIRC.
However the challengers shoot far better than the Borders outside. At 60 yds unless release is very good the arrows wont group while the challengers will, all 9's and 7's.
So after a paticularly bad round at Cleve, a Judge commented on how the arrows were leaving the bow sideways, I started thinking. The Borders are far more aggressively recurved and much faster, is it possible that I am underspined? Clearance, nock height and centreshot are all OK and I can bareshaft smack in the group at 30 Yds. The grouping and scores are good till 50 yds and then open up drastically.
So assuming you have spined your Borders and have no issues how does your choice compare to Eastons charts?
Brilliant limbs just need the correct arrows I think.

edit;
the ACC's have 70grn piles if I changed them to 50grn piles would it stiffen them 1 to 2 sizes?

[BorderBows]

Spine in short has little to do with the lbs of the bow, but the force of which the arrow is being pushed.
If the same arrow is being pushed to a speed of 180fps on one bow and 210fps on the other bow then there is going to be a difference in the force being applied to the arrow. It is still being pushed over the same distance say 20" of power stroke, and the arrow has the same mass to be forced into changing speed.
The Idea that all limbs need an approximate spine for the draw weight is the easiest way of measureing it. The fun begins when you consider that the more spine needed the more material needed in the arrow the heaver the arrow gets. that is why faster, heaver bows dont shoot hugely faster then light fast bows. The idea that more weight in the back and of the arrow/string/limbs the slower the bow goes, the less spine needed. Simply due to it being harder to accelerate the mass of limb/string/arrow. If you load up the front of the arrow, you start to have a different effect, in that the back of the arrow wants to accelerate, but the front weights a ton, so it wont move, effectivly weakening your dynamic arrow spine.
The next issue to consider when adding back weights and pile weights is you cant just go crazy. The balance point (FOC, Forward Of Centre) of the arrow needs to be up near the pile end, for example, when you watch someone throw the hammer in the field events you can see that the heavy end will overtake the light end. If the back of your arrow is heavier or two equal to the front then instability will take place in flight, thats why there are so many different spines of arrow.

You have just stumbled into the difference between static spine and dynamic spine.

Does that help or have i just jumped off the deep end.

[Flying Whale]

I would be surprised if you didn't need a spine stiffer for the TXS.

I found that with my TXG 32# limbs I was getting the same speed, sight mark and tune as 38# Hoyt G3's. The Border TX series are fast limbs.

[Andyakashrek]

Thanks for the reply, a trip to wales archery I think.

[Flying Whale]

Originally Posted by Andyakashrek

Thanks for the reply, a trip to wales archery I think.

Even if they turn around and tell you that the spine is OK....any excuse to go to archery shop must be good!!

[JohnK]

Originally Posted by Andyakashrek

the ACC's have 70grn piles if I changed them to 50grn piles would it stiffen them 1 to 2 sizes?

Almost certainly not. Point weight has only a minor affect on dynamic spine, and not enough to take you one full "size". Swapping point weight can make a difference if you're on the borderline of spine sizes, but by the sounds of it your set up is quite far out.

Good luck

[Andyakashrek]

Originally Posted by JohnK

.....by the sounds of it your set up is quite far out.

Good luck

Quite possible. I used to shoot challengers measured at 38# on fingers with 2012 X7's. When I bought the Borders They were also set to 38# on fingers. I also bought the acc's at the same time, they have the same spine as the X7's. They were shot as bareshafts at the time of purchase but only at short distance and I was advised that they were ok. However since then I have incresaed draw length by 3/4 inch and changed to a majesty string, this may have some bearing on the matter.
So having accepted my arrows are weak, both sets, I am faced with selling my borders and keeping my arrows and challenger limbs or buying new X7's and carbons and selling my challengers and 2 sets of arrows to get new ones.
NO CONTEST. Borders everytime.

So off to try arrows at proper distances and take photos for ebay.

[Andyakashrek]

After rereading my last post I suddenly had a thought. I took off the majesty string and put on a shot in dyneema string with one brass nock and one tied nocking point. I raised the brace height by an 1/8 to 9 1/8". Result. Arrow flight good and arrows in red or better at 60yds.
Presumably the heavier, thicker string has brought the ACC's back into tune as that's all I changed. Funny thing is I was shooting with someone using G3's at #40, #2 heavier than me, same draw length and bow length but using ACE's and I was hitting the boss harder than him with more penetration and flatter trajectory.
Seems I might be on the limit for spine. Indoors is fine but I have struggled with consistency since coming outside this year presumably due to the faster string and increased DL. Still, sorted now.
And no the Borders are not destined for ebay.

[Flying Whale]

Originally Posted by Andyakashrek

After rereading my last post I suddenly had a thought. I took off the majesty string and put on a shot in dyneema string with one brass nock and one tied nocking point. I raised the brace height by an 1/8 to 9 1/8". Result. Arrow flight good and arrows in red or better at 60yds.
Presumably the heavier, thicker string has brought the ACC's back into tune as that's all I changed. Funny thing is I was shooting with someone using G3's at #40, #2 heavier than me, same draw length and bow length but using ACE's and I was hitting the boss harder than him with more penetration and flatter trajectory.
Seems I might be on the limit for spine. Indoors is fine but I have struggled with consistency since coming outside this year presumably due to the faster string and increased DL. Still, sorted now.
And no the Borders are not destined for ebay.

Doesn't surprise me.

I got identical sight mark and identical tune from G3's @38# to my TXGs at 32# using ACEs at 100 yards.

[JohnK]

Originally Posted by Andyakashrek

Funny thing is I was shooting with someone using G3's at #40, #2 heavier than me, same draw length and bow length but using ACE's and I was hitting the boss harder than him with more penetration and flatter trajectory.

Funny for you, not for G3 owners