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Main Boards => PowWow => Topic started by: fireball31 on January 20, 2009, 05:17:00 PM

Title: probably a stupid question about spine
Post by: fireball31 on January 20, 2009, 05:17:00 PM
Lets say I'm shooting a 200 grain broadhead with a 100 grn brass insert.  Would the arrow have the same spine if I switched out to a 125 grn field tip and added 75 grns to the insert.
Title: Re: probably a stupid question about spine
Post by: JRY309 on January 20, 2009, 05:51:00 PM
That would be hard to say because you are talking about dynamic spine.When you have a 200 gr. head and 100 gr. insert you have affected the dynamic spine.The only way I know is you have to try a lighter static spine and see how it flys.There is no formula I've seen to go by.Carbons do not come in as many different spines as wood or aluminum.You would be dropping 100 grs. I would try a lighter spine with the new setup and then I would retune my arrow.
Title: Re: probably a stupid question about spine
Post by: fireball31 on January 20, 2009, 05:56:00 PM
I don't think I worded that very well. I am still keeping the 100 grn brass insert so both ways I'm keeping 300 grns up front. its just that 75 grns have switched from the tip to the back of the 100 grain insert making a 175 grn insert.
Title: Re: probably a stupid question about spine
Post by: Whip on January 20, 2009, 06:14:00 PM
I've never tried it, so not sure the right answer.  If you add weight to the insert I assume it goes deeper into the arrow shaft?  How far?  A regular insert is what, maybe a little over an inch long?  

I could see where if it ended up making a longer portion of the front of the shaft stiff it could have some affect.  Seems to me if that were the case the part of the arrow that would be subject to paradox would be somewhat shorter, and a shorter arrow will act stiffer.  Keep in mind, this is just a guess from a feeble mind, and I might be way overthinking this, but maybe something to consider.
Title: Re: probably a stupid question about spine
Post by: CHAD on January 20, 2009, 06:53:00 PM
I have set my arrows up the same way in the past and seen no differance in arrow flight. Just shoot your broadheads and fieldtips to the same point and if they group your good to go. Chad
Title: Re: probably a stupid question about spine
Post by: Dave Bulla on January 20, 2009, 07:33:00 PM
300 grains up front is 300 grains up front period.
Title: Re: probably a stupid question about spine
Post by: Apex Predator on January 21, 2009, 05:15:00 AM
I agree with Dave.
Title: Re: probably a stupid question about spine
Post by: sweet old bill on January 21, 2009, 05:40:00 AM
I think chad and dave are right on... would not make a big difference...
Title: Re: probably a stupid question about spine
Post by: fireball31 on January 21, 2009, 08:19:00 AM
thanks for the opinions guys.  I'll update once I get a chance to do some bareshafting.
Title: Re: probably a stupid question about spine
Post by: HATCHCHASER on January 21, 2009, 09:33:00 AM
I have found that it makes a difference because all of the weight is not on the tip.  Now your 300 grains is spread out.  It's like on the mfx arrows with the hit inserts the weight is spread out and it takes more to weaken spine.  Your mileage may very but it makes good sense if you look at the leverage of all of the weight being in the tip.  Now the arrow is gonna weigh the same, but it will act stiffer.
Title: Re: probably a stupid question about spine
Post by: snag on January 21, 2009, 09:56:00 AM
I would think with the same weight up front and a very small amount of difference in the positioning of that weight it wouldn't effect the spine but minimally. Give her a test drive and see is what I'd do.
Title: Re: probably a stupid question about spine
Post by: wingnut on January 21, 2009, 11:43:00 AM
He's keeping the 100gr insert in the arrow and changing the ingrediants in the tip but getting the same weight.  Heck the arrow doesn't know it's a different recipe.  Unfortunately he used the word insert instead of adapter when talking about the point.

Should shoot exactly the same.

Well unless you went from round to pointy tips.  Now that will make a difference.  LOL

Mike
Title: Re: probably a stupid question about spine
Post by: BobW on January 21, 2009, 11:51:00 AM
I think that if it was the insert then possibly yes (boy, that was a good answer), but since it is only the tip, no.
Title: Re: probably a stupid question about spine
Post by: vermonster13 on January 21, 2009, 11:57:00 AM
If trimming a carbon arrow a 1/4" can change the spine enough to show, then stiffening the arrow back a 1/2 inch will have some effect. How much will depend on how close you are to the spine you need for your bow now. If you were borderline you will see some effect, the farther from the target you get the more you'll see. If you had wiggle room then any effect should be negligible.
Title: Re: probably a stupid question about spine
Post by: Molson on January 21, 2009, 12:41:00 PM
If I'm understanding you right, you're going to remove weight from the tip and add it back on at the rear of the insert?  That being the case, I'll lean toward what Verm said.  I would think they will act stiffer simply because the weight has moved an inch or further rearward. The shorter the arrow, the more difference you would see. If you had good tune to begin with, you may not notice anything, but it has to change.
Title: Re: probably a stupid question about spine
Post by: Jeff Strubberg on January 21, 2009, 01:09:00 PM
The difference will be so minor you can ignore it.  It's a static section of the shaft.

He's not stiffening the shaft any farther back, just shifting the point weight distribution very, very slightly.