Carbon arrows woes

[wihill]

Just when I thought I had them figured out, I get confused again.

I got a set of 55# limbs for my Samick, and picked up some CX Rebel Hunter 4065 (.400 spine) to shoot with them.  On recommendation of friends that have shot this spine and bow weight, I cut the arrows down to 30" and installed 100gr adders to the rear of the insert, a 125gr tip and taped it down.  First shot flew tail left (I'm right handed), disassembled and reassembled with an additional 100grs worth of adders, and the tail kicked left even more.  Disassembled the arrow again and removed all the weight except for the 125gr tip - bullet hole on the bare shaft.  Swapped the 125gr tip for a 100gr tip, and finally got a tail right.

Why on earth does this bow like such stiff arrows?  I was trying to go with a stiff spined arrow so I could increase the point weight for an EFOC.  I don't really want to continue cutting down the arrow, as I've got an inch worth of clearence before the tip's on my knuckles, and I don't think I can trim enough off to get my point weight up past 100grs.

Maybe I should just pick up some .340 spine arrows and start with those - and maybe I'm not drawing the 28" that I think I am....

Ideas?

[Shawn Leonard]

I am sure it is cut way past center, but even at that you should be shooting closer to a .510 or so spine. I believe you are getting an opposite result and paper tuning a trad bow is almost impossible, you would have to have a darn near perfect release. I bet you go to a .500 spine and Heritage 150 cut to 30"s and shoot 175 point weight and you would be on the money. Shawn

[O.L. Adcock]

???????......If that .400 spine is on 26" centers that's about 60# spine, even less if it's on 28" centers. 55# draw, add #5 for each inch over 28", that brings you up to a 65 - 70# spine as a starting point. I can see where light points are the only ones close. Shawn is right, be careful trusting paper tuning or watching nock kick direction, it'll lie to you.

"On recommendation of friends that have shot this spine and bow weight,"

Keep them as friends, just don't take their advice!    ...O.L.

[wihill]

Originally posted by Shawn Leonard:
I am sure it is cut way past center, but even at that you should be shooting closer to a .510 or so spine. I believe you are getting an opposite result and paper tuning a trad bow is almost impossible, you would have to have a darn near perfect release. I bet you go to a .500 spine and Heritage 150 cut to 30"s and shoot 175 point weight and you would be on the money. Shawn

Thanks Shawn - you wouldn't believe it, but that (30" .500spine 175gr tip) is the near exact arrow I shoot from my 45# bows, and they're perfect.  

There must be something odd I'm doing at the release, or I'm pulling way over my supposed draw...

[jrchambers]

try cuting them a quarter at a time youll be suprised, ive heard that a quarter inch is like taking away 60 grains from the point, dont know if it is true but its gotta be somewhere around there for certain shafts.

[Jason R. Wesbrock]

Actually, paper tuning told him the correct information. Let's review:

 

Originally posted by wihill:
...I cut the arrows down to 30" and installed 100gr adders to the rear of the insert, a 125gr tip and taped it down.  First shot flew tail left (I'm right handed)

Tail left for a right-handed shooter indicates a weak spine.

 

...disassembled and reassembled with an additional 100grs worth of adders, and the tail kicked left even more.

He added more point/insert weight, thereby weakening the spine further. Paper tuning confirmed it by showing the tail end was kicking further to the left.

 

Disassembled the arrow again and removed all the weight except for the 125gr tip - bullet hole on the bare shaft.

He removed 200 grains worth of point/insert weight, stiffening the spine. The tuning results confirmed it.

 

Swapped the 125gr tip for a 100gr tip, and finally got a tail right.

Then he removed a little more tip weight, stiffening the shaft further. His tuning showed a slightly stiff shaft at this point.

His tuning procedure is sound, but since he's looking to shoot a properly tuned arrow with more point weight, he's going to have to start with a stiffer shaft.

wihill: you had the right idea in your last sentence. Pick up some .340's and go from there.

[Guru]

Jason    

What works for some,just doesn't work for others......

[Paul Mattson]

I just put a CX 45/60 on the spine tester. I came up with .425 (Modern Standard)  which equals out to around 72 lbs.  The bow is more likely past center.  Try building out the side plate some and see whats happens.

[Dmaxshawn]

Chris

After I talked you this morning have you had a chance to figure anything out?  Just curious.

Shawn

[O.L. Adcock]

Paul, "I came up with .425 (Modern Standard) which equals out to around 72 lbs."

OK, where is this "modern" standard written? As far as I can see a few manufactures have taken it upon themselves to create their own "standard" and the confusion factor that goes with it.   :confused:  ....O.L.

[wihill]

Shawn -

After I got off the phone with you I started packing, now I'm out in NYC.  As soon as I get back in town the process will begin post haste...  

I was hoping to put an order in for the BH's so they'd be in by the time I got back, but I guess that's pushed back a bit...

[wihill]

Originally posted by O.L. Adcock:
Paul, "I came up with .425 (Modern Standard) which equals out to around 72 lbs."

OK, where is this "modern" standard written? As far as I can see a few manufactures have taken it upon themselves to create their own "standard" and the confusion factor that goes with it.    :confused:   ....O.L.

OL - when I read that I thought the same thing, I believe he's refering to an actual tested spine vs the manufacturer spec?  (eg tested .425 vs manu .400)

  :confused:

[Jack Whitmire Jr]

Like Jason said above everyone is different, I shoot a real light spine out of every bow compared to mt Friends. As Ol said keep your friends, just get stiffer arrows and put heaiver weights up front.


Jack

[Paul Mattson]

AMO (ATA) deflection measured with 2 lb. wt.@26"
The Modern (ASTM) measured with 1.94lb wt @28"

 For instance lets use 500: AMO .500= ASTM .606.
which would equal around 52 lbs.

 Not trying to confuse anyone but, two types of arrows with to diffrent standards.

[Bill Carlsen]

I think  your instinct to go with a 340 spine (Easton or Beman) will get you closer to what  you want. I think Jason has it right based upon my experience.

[Jason Jelinek]

I've had good success using the bareshaft planning method.  Paper tuning works OK if you have a really good release.  I'll use paper tuning as a double check occasionally after I've completed the bareshaft planning method and have them fletched up.

Jason