Carbon Shafts & Inconsistent Spine Tolerances

[PastorSteveHill]

Does this make sense to you guys?  

I bought a couple of bare shafts to test out.  They were the Carbon Express Heritage 250's... Weighted them first.. There was a 10 grain variation in just these two shafts.  Not 2 grains, 10 grains... I know that isn't a big deal, but they came from the same unopened package, brand new...

Started testing them.. Cut to 31 inches, 125 gr. up front, field point and they shoot very weak out of my set up...

Now I have a Gold Tip 5575 cut to 31' and 125 gr. up front and it shoot almost perfect from 20 yrds. in, bare shaft.

Someone explain this to me.. I thought the CX 250 would be stiffer than the GT 5575 set up the same???

So my question is, how consistent are the carbon shafts as far as spine tolerances?  Thanks

[vermonster13]

Are you getting a false weak reading? The 250s are .373 spine and the 5575 are .400. (The 250s are also 3 grains an inch heavier)

[PastorSteveHill]

That's what I'm saying... They should be stiffer... They are showing quiet a bit weaker??? Doesn't make sense does it?

[PastorSteveHill]

I might add, I shot a couple of 7595 Gold tips and they are really stiff, which they should be. Even with 225 up front.  So I'm just wondering why the 250's are so weak?

Using a 5575 with 125 up front, 31' long, out of a 55 lbs. bow at 29.5' draw... Does this sound right?

[vermonster13]

55 at 28" or your draw?

[snag]

What are you shooting them out of Steve? The CE are spined at about 84# and the GTs are almost 79#. If you are shooting a cut to center bow either will work if setup right. You are shooting them 1.5" longer than your draw length. So you can cut them down quite a bit more to stiffen them up...a little at a time! I shoot a 55#@28" cut to center recurve. So, I can shoot a wide range of shafts. But I find the 250s cut to 29.5" with 100gr. inserts and 125gr tips(or 75gr. steel adapters with 160gr. broadheads) fly great.

[PastorSteveHill]

55 lbs. at my draw of 29.5

[vermonster13]

I'm a little surprised you are getting good flight from the 5575s with only 125 up front.

[clear]

My Hoyt GM2 at 50# at 28in(pulls 55# at my 29in draw)LOVES G/T 55-75 at 29.5in. Everybody thinks there to stiff but with a 125 gr.(broadhead or field tip) they fly and hit perfect! If there grouping at 20 bareshafting then let`m fly!!!

[vermonster13]

Problem with that set-up is you're only shooting around 7 grains a pound.

[DesertDude]

I have tested the spine on most of the carbon shafts out there. Most were off.  GT is the worst along with Axis. I have also tested each shaft for 360 deg spine,  they to were off.......

[McK]

I have noticed a lot of variation in the carbon shafts I have tested.  Most recently with some Vapor 4000 shafts.  Bought some Vapor 2000s at the same time. Some of the woodgrain 4000s actually spined less than some of the 2000s. One of the 4000s spined a lot stiffer than most and weighed 45gr more. This was using a homemade spine tester that always checks out consistent with aluminum shafts.
McK

[wapiti]

Heavier shafts decrease dynamic spine. A heavier shaft will require higher static spine with the same set up. If you are on the lower end of your spine range for that bow/set up you may not get those shafts to fly well. Experimentation will tell.

[O.L. Adcock]

Steve, do yourself a favor and don't try to compare one kind of shaft to another as to "why" they behave the way they do. Small differences in diameter, weight, nock fit, ect...Will drive you nuts. If your trying to set up a dozen shafts for a bow, get a dozen in the ball park and do what you got to do to tune them. Arrow makers love it when folks buy 16 different kinds of shafts trying to find the "one" that flys. Between length, point weight, and side shelf thickness, most any bow will shoot over a 20 pound range....O.L.

[PastorSteveHill]

Here is what I cam up with (not that anyone is waiting to hear, just thought it might help someoneelse down the road.)

The CX Heritage 250 cut to 31' with a heavy wrap on it (28gr.) with 125 up front... Bare shafted excellent out to 20 yards. After that, well it shows weak still, but that is ok for now... I got good results from 20 yards. So I fletched one up. Groups well... Small adjustments in nock point.. Very small.. Bingo... Got a fletched shaft and put a broadhead on it and did test with B/H and field points, both fletched. and Almost perfect. Out to 35 yards.. I feel pretty good about this set up.. I'm in the mid 500 range as far as weight goes. and B/H and field points are real close... Thanks guys...Steve