Arrow spine program

[marshhunter]

My current arrows are 11.5% FOC. I am wanting to bump this up to around 16-18% FOC. My draw length is 27" and I can cut about 1-3/4" off of my current arrows, but I need someone to run them through the arrow spine program to see if by cutting 1-3/4" off, I will be able to add enough weight to the front and not be under spined. Current bow and arrow specs below.

My plan would be to cut from the front and install new gold tip inserts so that i can screw in the desired weights, thus being able to keep all of my 100gr BH and FP.

Current bow:
Mathews Z3
IBO 330 FPS
70lbs
27” draw


Current arrow:
Beeman ICS Patriot
27-3/4” long
9.3 GPI
340 Spine
100gr BH and FP
(3) 2" Blazers
Standard aluminum insert
Lumenock
414g
11.5% FOC

Is my plan achievable with my current arrow set up? I am trying to not buy new arrows, just utilize the extra length on the ones I currently have.

[Crippl3creek]

To me it looks like you're already a little too stiff with current length. If you keep your arrows at 27.75 and up point weight to 150 gr or increase insert weight by 50 gr you're spine will be optimal and your FOC should be around 14-15%.

[enewman]

I use the free program from victory.

I don't know how much a lumenock weighs. so I used 25gr. what you have now is good.
what I did was add 75gr to the insert on the program. those arrows should be good cut at 26"

only one way to find out. build just one and test it.

would like to see how you are getting 11.5%foc. that lumenock should be killing it. I would have guessed around 8 or so. but hey I could be way off.

[marshhunter]

I use the free program from victory.

I don't know how much a lumenock weighs. so I used 25gr. what you have now is good.
what I did was add 75gr to the insert on the program. those arrows should be good cut at 26"

only one way to find out. build just one and test it.

would like to see how you are getting 11.5%foc. that lumenock should be killing it. I would have guessed around 8 or so. but hey I could be way off.

I added it all up but when i put all the info in my phone I left off the weights of it all. according to a google search, the lumenock weighs 12gr

[marshhunter]

To me it looks like you're already a little too stiff with current length. If you keep your arrows at 27.75 and up point weight to 150 gr or increase insert weight by 50 gr you're spine will be optimal and your FOC should be around 14-15%.

So if I was to increase insert weight by 100 gr and cut the arrows, would that achieve the desired FOC of 16-18%?

[muddyfuzzy]

Don’t beat yourself up over achieving “X%” FOC, the goal is to build a good tunable arrow that works with your setup. Do this, run the appropriate weight to get the mass up and let the FOC take care of itself.


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[marshhunter]

Can someone run this arrow through archers advantage or the like?

Gold Tip XT Hunter 340 Shaft 8.9 GPI @ 26"
Fletching: (3) Blazers 18Gr total
Nock: Nocktournal 22Gr
Insert: 100 gr
BH: 100 gr

Based on the Gold Tip FOC chart this should get me around 15% FOC, but I am wanting to make sure the 340s are the correct spine.

[Black-N-Red]

I think the 340’s will be a touch weak with the 100gr inserts. I would get some 300 spine, some FACT weights in 10, 20 & 50gr & the 100gr inserts. I think with a 27” arrow, 100gr insert & 40gr begins the insert you’ll be good.

This just me. I get arrows that are to stiff & start adding weight till they fly good. I don’t worry to much about weight or speed. My Full Throttle I run 250 spine GT Pierce out of it. All my other bows get 300 spine Velocity’s with 100gr inserts to start with.


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[CALopez]

Have you tried switching to feathers? I shoot a Z7 Magnum, and switched from blazers to Rayzr feather and my FOC went up as well as all the benefits from feathers. I do shoot a heavier arrow though at around 600 grains