Help me build my elk arrow

[quackadikt]

Vap 350 with SS inserts and a 150-175gr head. I'm shooting a very similar spec'd setup to you(I'll be b/t 55-60lbs and 28" from an Obsession Turmoil RZ), and that's the arrow I'm going to be hunting with this fall(elk and mulies if I draw, and TX deer). With a 125gr head I weight components yesterday at 466. Throw a 150 on and you're at 491, 175gr puts you at 516. FOC should be pretty stout.

[canny]

Vap 350 with SS inserts and a 150-175gr head. I'm shooting a very similar spec'd setup to you(I'll be b/t 55-60lbs and 28" from an Obsession Turmoil RZ), and that's the arrow I'm going to be hunting with this fall(elk and mulies if I draw, and TX deer). With a 125gr head I weight components yesterday at 466. Throw a 150 on and you're at 491, 175gr puts you at 516. FOC should be pretty stout.

Awesome! I failed to mention that my bow setup will change as I just picked up that Hoyt Defiant in the Classifieds.

[quackadikt]

Awesome! I failed to mention that my bow setup will change as I just picked up that Hoyt Defiant in the Classifieds.

Didn't see that you already built your arrows...My bad!

Forgot to include that I'll probably shoot a 150gr Stinger Buzzcut w/ bleeders. If not, then maybe a 150gr Kudupoint or Cutthroat. I don't know if I'll go to 175 heads just because they're so much harder to find, and aren't cheap when you do.

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[enewman]

Well here's the updated plan. I did some dynamic spine calculations using the Stu Miller Calculator. My normal set up that I use has a Dynamic Spine of around 410. I figured that I know this spine will work with my set up so I will be building a heavier arrow with the target of around 410. Here's my build specs:

-Carbon Express Maxima Red 350s cut to 28" (normally these would be too stiff)
-100g brass insert (I could have went smaller but I would have had to buy heavier heads and I already have a lot of 100g points)
-100g broadhead (Shuttle T Locks)

This should give me a total arrow weight of 495 grains with 16% FOC and a dymanic spine of 412 which is right on point with what my set-up likes.

Isn’t the Stu calculator for trad shooters

[canny]

Isn’t the Stu calculator for trad shooters

It is...but you can use it to compare arrows. Build what you know works...record the dynamic spine then build a new arrow that matches the original dynamic spine. Since I went to a stiffer arrow I needed to know how much weight to add to bring it back down to what my setup likes.


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[enewman]

Ok. Just info. Compound bows don’t care what spine it is. It’s all in tuning. Underspined arrows don’t group well so that is why we don’t shoot them. Over spine arrows is up to the shooter. A person with good form and grip can shoot a rod. It won’t matter. That is the best part of compounds shot with a release.

[canny]

First off I need to apologize as I made a critical error in that I did not convert the published ASTM spine to AMO Static Spine. This is why the Dynamic spine value was so large. After correcting that mistake I realized that I would need to modify my arrow build.

If I were to use a "normal" factory hunting arrow, Carbon Express Maxima Red 250 @ 28" with a 100g broadhead and the standard 11g insert I would have a dynamic spine of 117.4 and a FOC% of 9.2.

In order to match that dynamic spine with a heavier arrow with more FOC using the components I have I would need to build the following:
Carbon Express Maxima Red 350 cut to 26.5"
Using a 100g broadhead and a 100g insert this would give me a dynamic spine of 117.0. However it would give me a total arrow weight of 486 with 16.5% FOC.

[enewman]

ontarget program

[enewman]

i did 26 not 26.5 so its off just a bit

[canny]

i did 26 not 26.5 so its off just a bit

Also on the Maxima 250 that build is with the standard 11g insert not the 100g. I’d be curious to what it will show with the Hoyt Defiant I just bought. IBO 331fps with 28” draw.


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[enewman]

Also on the Maxima 250 that build is with the standard 11g insert not the 100g. I’d be curious to what it will show with the Hoyt Defiant I just bought. IBO 331fps with 28” draw.


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which arrow and how long.

i do want to add. programs are a starting point only. i do not believe you can cut the arrow to the length the program states and it is correct. to many variables. this is why i dynamic tune.

i posted a paper on here looking at spine it shows why

[enewman]

here is the link

https://1drv.ms/w/s!AtVqxLy9AZcGhTUuQBiHAB9m9LSF

[canny]

witch arrow and how long.

i do want to add. programs are a starting point only. i do not believe you can cut the arrow to the length the program states and it is correct. to many variables. this is why i dynamic tune.

i posted a paper on here looking at spine it shows why

Here's my thought process, hope I can explain it well enough:

First off I dont know how much weight I can add to a stiffer arrow before I have added too much and the arrow has a hard time stabilizing. Knowing this I took what I would consider a "normal, factory" hunting arrow for my draw weight and length which would be the Maxima 250 @ 28". This arrow would have all standard equipment such as the 11g factory nock and a 100g broadhead. I used this info to calculate dynamic spine for that set up. This dynamic spine was then my target for my heavy arrow build. Basically it allowed me to play with shaft spines, insert weights, and broadhead weights to build a heavier arrow that still had the same dynamic spine as the "normal, factory" arrow.

[enewman]

nothing wrong with what your doing. there are ways to see if the spine is reacting correctly.

one you can take several bare shafts with different tip weights. set bow up to stating point. back up 10 feet. shoot each arrow through paper. the one with the tear closet to a bullet hole is the arrow reacting the best with that tip weight.

second you can take your bow at starting point and shoot one fletched arrow and one bare shaft and shoot at 20 yards. if bare is low nock high you need more spine. if its high and nock low need more tip weight. this is dynamic reaction tuning.

problem with some of this tuning is its very important to nock tune first or you can get bad results.

one thing I've seen since I've been testing arrows are they are not spine at what they say. this means programs are off. now how far can the be off i don't know. that is testing I'm still doing. tim gillingham told me .030 my ocd wont let me have that. i don't want more then .010 spine difference between the dozen.

[enewman]

this method checks reactions

https://1drv.ms/w/s!AtVqxLy9AZcGhAyHZPxIO1153s-d