Matching bow dynamic spine to arrow dynamic spine

[Bobaru]

What's the right arrow for a particular bow and archer?  Stu Miller has provided a great service with his dynamic spine calculator.  

I've been collecting data from people who post up what bow and arrow combination they are using.  Usually it's from when they killed an animal.  Below is what I've captured, and in paranthesis I have calulated the bow dynamic spine and arrow dynamic spine using Stu Miller's calculator and an occassional small assumption.

At the bottom of Stu's calculator, he put an area for an archer's "personal form factor."  I left that at zero.  

I post it here for anyone's interest.  I only wish I had more data. I find this all facinating and thought others might as well.

(1) One hunter’s arrow…shot a doe – arrow sticking out both sides, lung-liver.
Bear Super Kodiak 50@28, 2315 xx75 w/ magnus two blade.
     Must be ~ 185 grain head with about 16%FOC.  The FOC didn’t seem to help him…
(bow DS= 67  arrow DS= 79.3)

(2) "This is a buck I havested the third week of October. Shot with a Black Widow PSAX 62" 55@30" with 640 grain Beman MFX 400 with a 145 Journeyman head with a steel adapter."  (bow DS= 72.2  arrow DS= 35.8)

(3) One successful hunter’s elk bow -  "54# @ 30 shooting a 125 gr Magnus 2 blade on a 31” 2117."
(bow DS= 71.2  arrow DS= 64.2)

(4)  "Blacktail TD Recurve: 66", 42# @ 30". Arrow: 32", 2117. PW: 200 Grains. AW: 637 Grains. GPP: 15.16"
 (bow DS= 65.0  arrow DS= 42.6)

(5) "Blacktail TD Recurve: 66", 37# @ 30". Arrow: 32", 2114. PW: 180 Grains. AW: 550 Grains. GPP: 14.86"
  (bow DS= 59.4  arrow DS= 35.7)

(6)  "Bear Grizzly 60#@28" shooting 30" Easton 400s tipped with 150 grain Rothhaar Snuffer."
 (bow DS=77.4  arrow DS= 65.9)

(7)  "Ended up being a 34 yard shot with my 60", 68# @ 29" MOAB I'd just received from Jim this summer. 31" Gold Tip 75/95 w/260 grain Magnus 1's on the end." (bow DS= 85.7  arrow DS= 57.6)

(8)  "60" Pittsley Predator Classic Recurve, 10 Strand D97 String w/2 Silencers, Selway Side-Mount Bow Quiver.  Beman MFX 500 Classics @ 29.25", 250 Grs. Up Front, 3 X 4" Feathers, 555 Grs. Arrow Wt., 48# @ 26.75", 161 FPS @ 11.5 GPP, 21% F.O.C., 3 Fingers Under."
  (bow DS= 69.9  arrow DS= 42.4)  

(9)  Took an 8 ft gator:  "50# Zipper SXT w/evolution recurve limbs. 300 spine axis full metal jacket with point weight of 550 grains for a total arrow weight of 950 grains."
 (bow DS=67.0  arrow DS=~33.5)


#4 & #5 come from Nightwing who is very proud of his set up and says he shoots darts.  He's paper tuned these at 7 yards and they have perfect holes... and I believe he has also bare shaft tuned, but can't remember for sure.

My conclusions are that personal form factors are probably as important here as anything.  I've harvested two deer with a set up identical to # 3 above - with complete pass throughs both times.

Food for thought!

[Art B]

"My conclusions are that personal form factors are probably as important here as anything".

Totally agree! Art

[cedar]

I think the distance cut to center(+ or -) is a huge factor.  I know my longbows and recurves at the same poundage are far different dynamic spine due to the cut.

[Bobaru]

John49:  I know you're correct on the "cut to center."  I only had the info for Night Wing.  His Blacktail bows are cut -3/16."  On the other bows I had to make an assumption.  That assumption was -1/8." I'm showing with Stu's calculator that 1/16" can make about 5 pounds diffence in the dynamic spine.

The string used make a difference too, but smaller, and of course all the stuff we put onto the string....

I've been debating buying some stiff carbon arrows and putting heavy weights to get FOC of about 20.  I've been trying to figure what all this data means to me so I can best make an informed purchase.  Surely, I'll have to play some with head weights.  ...  And, in the end, I will probably go back to my 2117 with 125 gr heads.