Dont try this at home test

[LB_hntr]

I have been tuning arrows for my new longbow and had to satisfy a curiosity. So I took a few shot at 20 yards with a big magnus 1.5inch wide  broadhead on a bare shaft with 30% efoc. Pretty interesting.

http://tbwpodcast.com/video-37-efoc-bare-shaft-broadhead-test/

[Alexander Traditional]

So you're saying you think that it is doing that well because of the high percentage of weight up front? How do you figure the percentage? I've got a 626 grain total arrow weight,and the weight up front is 322 grains. That flies great for me. I know that's probably fairly high,but don't really know how to figure it.

[JD Page 1965]

Interesting! Thanks for sharing the results, now stop shooting so damn much before you blow something out and can only write about traditional archery..  

Originally posted by Alexander Traditional:
So you're saying you think that it is doing that well because of the high percentage of weight up front? How do you figure the percentage? I've got a 626 grain total arrow weight,and the weight up front is 322 grains. That flies great for me. I know that's probably fairly high,but don't really know how to figure it.

Enter that arrow into the Stu Miller Dynamic Spine calculator and it will calculate the FOC for you.

Bisch

[Alexander Traditional]

Thanks Bisch. I couldn't find one on the Stu's that would let me dial it in without downloading it. I found something on 3Rivers site that let me dial it all in,and it said I had right at 26%.

[Cyclic-Rivers]

I was waiting for disaster.

[Bladepeek]

The AMO method is to measure your arrow from base of point to valley of nock. This is your total arrow length. Then, balance your arrow on something fairly narrow (pencil, triangular ruler). Mark the balance point with a Sharpie and measure from the valley of the nock to the balance point. Divide the balance point measurement by the full lenght of the arrow, subtract 0.5 and multiply by 100 (to get percentage rather than  dec imal value).

If the arrow balanced at the mid-point, and the arrow is 30" BOP to nock, you would have 15/30 = 0.5, minus 0.5 = 0*100  = 0%.

If it balanced 20" from the valley of the nock,

20/30 = .667, - .5 = 0.167 * 100 = 16.7% FOC.

By the way, if I calculate my arrow FOC using Stu's calculator, I get the same FOC, so I would guess that's the method Stu used in his calculator.

[Dr. Ed Ashby]

The Papua New Guinea natives shoot these massive broadhead arrows unfletched, and consider 25+ yards to be 'good shooting distance'. All are over 30% FOC.



Ed

[LB_hntr]

Originally posted by Dr. Ed Ashby:
The Papua New Guinea natives shoot these massive broadhead arrows unfletched, and consider 25+ yards to be 'good shooting distance'. All are over 30% FOC.

 


Ed

I remembered you saying that many arrows were shot with broadheads on no fletching. I could not remember the percentage of efoc you mentioned but it was one of the reasons I wanted to try the test. I'm not gonna lie, I first shot that arrow at 3 yards, then 5, then 10, then 15, the 20 just to see where things started to get screwy. It wasn't until about 28-30 yards that my nock high issue started sinking my impact location noticeably.
Once I get my nock hieght perfect I'd expect near perfect flight at any distance base on what I saw whiledoing those shots.

[nineworlds9]

This is pretty neat.  I've never tried 'that' much FOC.  Gives new meaning to 'spear chukka' LOL.