Check my spine, please.

isItFallYet

Senior Member
Joined
Sep 24, 2019
Messages
204
There are similar threads, and I didn't want to hijack them. So... I think I may be underspined, but I shoot well out to 80 yards with this setup, but there's always room for improvement, right?

My setup:
Mathews Vertix 70lbs
243 IBO
5mm axis @28"
100 grain QAD Exodus bh
Finger release
No added weight, and a total of 416 grains (not too concerned about increasing weight because I know this arrow can kill an elk at 68 yards)

I have been shooting 340 axis 5mm, but after looking at Easton's calculator, it looks like I should use a stiffer arrow. I'm about to buy another dozen arrows, and am wondering if I should increase the spine.

Easton says to add 5lbs if ibo is over 340 fps, add 5lbs if brace height is less than 6.5", add 5lbs if using a finger release.
so...
70lbs + 5lbs (343 IBO) + 5lbs (6" brace height) +5lbs (release) = 85lbs with a 28" arrow.

The calculator says to use 240-300 shaft size.

Keeping in mind that I only have a month to retune, would you make the change, or would you continue with what has been working?

1627591988647.png
 

Rob5589

Senior Member
Joined
Sep 6, 2014
Messages
3,722
Location
W Sac CA
Personally, I would have gone to a .300 right off. But if it's shooting well, it's shooting well. The shaft is short enough and the front weight is light enough to make it work. If you wanted to run more weight up front, for sure move to a .300 or maybe a .250.
 

danwattsmessick

Senior Member
Joined
Feb 26, 2012
Messages
184
Location
Spokane, WA
Quite a short ATA bow to be shooting fingers, is it comfortable?

As someone not using a release aid, I would probably have gone with a stiffer arrow. That being said, if you are shooting well (with fingers no less) out to 80 yards - don't change a thing.
 
OP
isItFallYet

isItFallYet

Senior Member
Joined
Sep 24, 2019
Messages
204
Quite a short ATA bow to be shooting fingers, is it comfortable?

As someone not using a release aid, I would probably have gone with a stiffer arrow. That being said, if you are shooting well (with fingers no less) out to 80 yards - don't change a thing.
Sorry, I meant a finger release.
 

Billy Goat

Senior Member
Joined
May 6, 2018
Messages
4,638
Location
Shenandoah Valley
You shooting fingers on a vertix?


Finger release means using 3 fingers and a tab or glove.

I have to suspect you are actually using a wrist strap with an index release, that's just a normal release aid.
 

Billy Goat

Senior Member
Joined
May 6, 2018
Messages
4,638
Location
Shenandoah Valley
I'd be using a 300 with what you have listed. But that's just to make it easier.

If you are getting a good broadhead tune as it is you don't need to change a thing, stay with the 340's.
 

danwattsmessick

Senior Member
Joined
Feb 26, 2012
Messages
184
Location
Spokane, WA
If you're using some form of release aid (not shooting using your actual, factual fingers to hold and release the string) you're fine.

Assuming you're shooting a 28" draw, you could easily cut those arrows down to 26.75" and get a 400 spine to tune. I know this because for years I shot a 400 spine arrow out of every 70# bow I owned.

These charts cause so many people to overthink and over complicate this stuff that I wish we would just do away with them all together.
 
OP
isItFallYet

isItFallYet

Senior Member
Joined
Sep 24, 2019
Messages
204
You shooting fingers on a vertix?


Finger release means using 3 fingers and a tab or glove.

I have to suspect you are actually using a wrist strap with an index release, that's just a normal release aid.
Thanks for clearing that up! I’m definitely using a mechanical release.
 

Samdemarais

Senior Member
Joined
Jul 27, 2017
Messages
435
If your asking about your spine you must not be shooting that well at 80 yards with broadheads…..?
 
OP
isItFallYet

isItFallYet

Senior Member
Joined
Sep 24, 2019
Messages
204
If your asking about your spine you must not be shooting that well at 80 yards with broadheads…..?
That’s not a problem. I am confident in my shooting. 5 arrows in a grapefruit at 80. I’d like for it to be an apple.
 

Latest posts

Featured Video

Stats

Threads
202,989
Messages
2,095,667
Members
50,993
Latest member
DavyCrockett
Top