Changing arrows for increased gpp

[DaveBriner]

Hello all,

Little help if ya don't mind.  Below is my current set up.  I'd like to get my total arrow weight up some.  Currently at ~ 9.7gpp.  I could add the full length inserts to these arrows, but I'd like to just switch arrows so I don't have to order these every time I get new ones.  The heavier heritage (250 and 350) have weaker spine, right?  These 150's shoot pretty sweet right now.  What's the best course of action?

Bow-  SAIII, 62", 51# at 29" (I only draw 28")

Arrows-
CE Heritage 150's at 29"
100g snuffer + 50g brass insert + screw in insert
3 X 4.5" shield fletch
total weight ~ 475g, ~9.7gpp (assuming 49lb@28")

Thanks in advance,
Dave  

[E. Texas HillBilly]

Hello Dave,
            I am certainly no expert but I believe the 250's and 350's have a stiffer spine because they are made for heavier bow weights. I personally shoot a 70# longbow and full length 350's with a very heavy broadhead. In addition to that I have weight tubes in all of them for added mass. They shoot perfectly for me that way. If I were to shorten them they would stiffen up so much as to not shoot well. The 350's are very stiff which is one reason I shoot them full length. Another is of course weight. I like very heavy arrows. My bow likes 'em too. Hope this helps you some.
                          -Hillbilly

[Bradd]

I just posted a new thread for Goldtip spines on carbons because I just upped my grains and length too.  

First, figure out what spine you need for the length of the arrow you want to end up with, from the chart.  

Next, find an arrow, that when the grains per inch (almost all charts list that) multiplied by the length, + about 70 grains for insert and fletching + the point weight you want, adds up to the total weight you want to end up with.  Hunting arrows will weight more than target arrows so be careful with the charts!

Next, go about 1-1.5" longer than your required length and have the inserts and tips installed. Cut them down from the fletch end 1/2" at a time until they bareshaft SLIGHTLY WEAK (hitting to the right of a group) because when you add fletching, they will stiffen.  If, after fletching, they are still slightly weak build the backplate out until they fly where you want!

Hope this helps!

[Bradd]

Opppsss....sorry...I couldn't attach the chart.  Go here to get it
 http://***********.bowsite.com/TF/lw/thread2.cfm?forum=23&threadid=183902&messages=4&CATEGORY=9

[DaveBriner]

Originally posted by E. Texas HillBilly:
I am certainly no expert but I believe the 250's and 350's have a stiffer spine because they are made for heavier bow weights. I personally shoot a 70# longbow and full length 350's with a very heavy broadhead.

Interesting, I always thought that the spine number was some unit of distance the arrow flexes with a standard amount of applied force.  Thus as the spine number goes up, it means that the arrow flexes more, and so has a weaker spine.  That's the way the bemans were labeled anyway.

Obviously, if you're shooting a 70# bow with the 350's with good results, then the carbon express nomenclature is opposite of what I'm saying.

I would rather add/subtract brass weights as opposed to having to tinker too much with cutting down.  I don't have a cutoff tool, plus, to test your arrows you're always comparing to identical fletched arrows right?  So I would have to refletch every time I made an adjustment?

Thanks for the help guys,
Dave

[Bradd]

Ahhhh...yes, there is one manufacturer that uses opposite numbers but I can't remember which one right now.  Better to look at the arrow chart and it will show what spine to use...IE.600, .500, .400 etc

Brass weights should get you there.  If you can't find the answer here, check on tradtalk.com or archerytalk.com

[Apex Predator]

If you are happy with the 150s spine then you could probably shoot the 250s with 100-150 extra grains in point weight to get close to the same spine.  This would put your arrow weight up to where I like them.

[hunt it]

Dave,

Get yourself some Beeman MFX 400 and use 250gr or 300gr field points. See how they fly and then chose broadhead setup. You can buy some 300xtreme broadheads from Bob Morrison, he also sells the 300 & 250gr field tips. Want cheaper broadhead option use a 160gr STOS with a 125gr steel adaptor. This is my set up for a 53# bow. The higher the FOC the better you'll find they fly.

[E. Texas HillBilly]

Hmmm, now I'm starting to wonder. I know my wife's arrows are Carbon Express Heritage 90's. Her bow is a 38 pounder. They are very flexible and the 150's I used to use in a smaller bow are more flexible than the 350's I use now. I was under the impression that for C.E. arrows the higher the number meant the stiffer the spine because the walls are thicker adding weight as well. If someone can clear this up it would be much appreciated.
                       Hillbilly

[pooahl]

here you go:

size: 90  gpi: 9.4  spine .530

size 150  gpi: 10   spine .487

size 250  gpi: 11  spine .373

size 350  gpi: 12  spine .320

This is from their website.

[DaveBriner]

Originally posted by pooahl:
here you go:

size: 90  gpi: 9.4  spine .530

size 150  gpi: 10   spine .487

size 250  gpi: 11  spine .373

size 350  gpi: 12  spine .320

This is from their website.

Thanks pooahl,
Those spine numbers are what Beman uses to name their arrows.  I guess it confused people too much so most manufacturers went with the CE nomenclature.
Dave