Will broadhead length change the spine of the arrow?

[BassBow]

Hello,

Ok, I heard through the grapevine that having longer broadheads, longer than your field points that is, can change your arrow spine? Does this happen? The advice given was to shoot lower gr broadheads if they are longer and add length to the arrow thus compensating for the change in spine.

I shoot trad only 500's with 125 gr. field points and Magnus Stingers 125 gr. They are significantly longer....see what I mean. My tuning has been successful as of lately, but prior to my bare shaft broadhead tune(compromise) recently the broadheads and field points flew much differently.

Is there truth in this? I wanna know ; ).

[Charlie Lamb]

Not enough to matter.

[Red Beastmaster]

I've been wondering the same thing.

Here's my scenario:

 My alum arrows fly perfectly with 125gr field pts, cock feather in or out makes no difference.  When I install a 125gr broadhead on that same arrow I get a kick that will only go away by turning the cock feather in.

Could the longer overall length be changing the spine a bit? I have no other explaination.

I've been at this long enough to pretty much know what I'm doing, but this has me puzzled. I just turn the cock feather in and go hunting, no biggie.

[ChrisM]

Lowering the weight would stiifen the spine but lengthing the shaft would then weaken the spine making it a wash.

Like charlie said it won't matter unless you arent really tuned.

[BOHO]

I dont think the length will matter but a significant change in weight would

[Cory Mattson]

?????????? I have never heard that. We understand what is between NP and BOP effects spine -weight matters - never heard of the length being a factor ? Can't say it would never but it has never hurt us and we shoot broadheads bigger than tweety birds. If the grain weight is correct they fly same as a field point of equal weight

[RK808]

I haven't seen it matter in my personal experience and I shot all kinds of lengths.  Up to 15gr. difference up front also seemed to have little to no effect.  
The point weight doesn't seem to affect spine as much as shaft length does.

[JamesKerr]

I have heard that rumor as well but find it to be totally inacurate if you have bare shaft tuned. If you have not gone through some sort of tuning process it might be plausible.

[BassBow]

Great advice gentlemen. I appreciate it greatly. Now for the reveal. This archer "grey archer" on YouTube posted a video saying that if you shoot 125gr field points and you shoot long broad heads you need to lower your broad head weight by at least 25 gr. It shocked me a bit. A lot of people are watching his videos. Including me.

[bornagainbowhunter]

The only way it would effect the tune, is if you were only borderline tuned anyway, imo.  I used to shoot several different broadheads with several different lengths and never had a problem.  I can shoot + or - 25gr and the only thing that changes is noise level.  I get a "tink" from the shaft slapping the shelf.

God Bless,
Nathan

[ChuckC]

Some questions to ponder, though I agree with Charlie here.  (we tend to fuss about things that really don't matter).

If you lengthen a shaft with same shaft material, it will weaken spine, but if we lengthen it with substantially stiffer material (broadhead), will it still do that ?  How ?

If you add a broadhead where most of the weight is near the arrow vs a longer, weight forward broadhead where the weight is . .  say 6" out, will that matter ?  

If the original arrow is say 6" longer than needed and this overhang does not impact the bow at all during release, will there be any noted changes ?

If simply flipping the arrow over (cock in)does that show a broadhead issue or an issue with the original tuning of the arrow, or even placement of the cock in the wrong plane ?

Again,  I think that 99 % of us would NEVER notice a change from shorter to longer broadheads.

Just shoot.

ChuckC

[Terry Green]

If it does.....you are too borderline in your tune.

[Red Beastmaster]

My set up is Brackenbury Quest 45# @ 27", 1916 alum cut to 28" BOP. It is the arrow recommended by the Easton chart.

Like I said, perfect flight with target points.

I've tried shafting sizes above and below but get best flight from the 1916's.

The same arrow flies perfectly from my 47# Thunderhorn longbow. That being said, they may be a tad week for the center shot recurve.

Regardless, I have no problem turning cock feather in with broadheads to achieve good results. It works, good enough for me.

I gave up tinkering with equipment when I retired the compound back in '87.  

[BassBow]

I just shot my 100gr muzzy 3 blades and the spine definitely stiffened up. It was very interesting. You guys have never seen this happen? Shoot a lower grain Bh(when it is significantly longer) and a heavier field tip?

[alligatordond]

Charlie and Terry pretty much nailed it.

[JParanee]

Naaaa  

[gringol]

The length isn't the problem, it's the wind vane you have on the end of your arrow.  Paradox turns the side of the head into the wind and too much of that makes it hard for the fletching to catch up.  BHs make tuning problems that you missed really obvious.

[JimB]

I'm no no aeronautical engineer but I did learn something last Fall after pile-driving a 200 gr Grizzly broadhead into a rock.The tip curled and when trying to straighten it,3/8" of the tip snapped off.That left the broadhead app. the same length as it's matching field point.The 3/8" piece that snapped off,weighed 6 grs.

The truth is,that part of the broadhead that is longer than your field point,is the lightest part of the broadhead.

You can also test it yourself.Find the balance point of your arrow with field point on.Mark it with a pencil.Now,install your broadhead and check balance point again.With my longer Grizzlies,the difference is about the width of a pencil mark.Think that will affect things?

[BassBow]

Here is the video. Food for thought.  

[Overspined]

Yes, I have noticed a slight change, but not always.  I always tune to broadheads and go backward.  Then you will sometimes find that an arrow with a broadhead of 190 prefers a fieldpoint of 160, although not that common.  I think each bow with different center shot will be the deciding factor if your arrows are borderline.  Also, I shoot cock feather in all the time because clearance is better for me. Sometimes form is a cause as well.