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Main Boards => PowWow => Topic started by: flyguysc on August 15, 2017, 02:22:00 PM

Title: Grains per inch ?
Post by: flyguysc on August 15, 2017, 02:22:00 PM
To figure grains per inch one divides the over arrow weight by length,which in my case it's 495 grs.arrow weight divided by length 27.5 bop which is 18 grs. per inch. Seems like a lot. So I'm I using the right formula? Using Ace 145 grs. heads with Sure wood Douglas fur shafts.
Title: Re: Grains per inch ?
Post by: BOHO on August 15, 2017, 02:31:00 PM
Wood is always heavy
Title: Re: Grains per inch ?
Post by: slowbowjoe on August 15, 2017, 05:12:00 PM
What poundage are you shooting? I think grains per pound is a better way to look at total arrow weight.
Title: Re: Grains per inch ?
Post by: KodaChuck on August 15, 2017, 05:58:00 PM
Yep....think you are looking for grains per lb which is more meaningful....shooting 10 grains per lb would suggest a bow draw weight of approx.  49 lbs. What draw weight are you shooting?
Title: Re: Grains per inch ?
Post by: old_goat2 on August 15, 2017, 11:02:00 PM
And if you are wanting to know grains per inch, it's the shaft weight only, not tip, fletches or even the nock weight included, but like others eluded, it's probably grains per pound you're wanting to know.
Title: Re: Grains per inch ?
Post by: flyguysc on August 16, 2017, 08:08:00 AM
I'm shooting 50.lbs DW @26.5"DL .Shooting a Howard Hill Black Mamba 66" asl long bow set @ 50.lbs @ 26.5" dl.
Title: Re: Grains per inch ?
Post by: flyguysc on August 16, 2017, 08:14:00 AM
So it should be 9.9 Grs. per inch right? 50x9.9=495
Title: Re: Grains per inch ?
Post by: The Whittler on August 16, 2017, 08:33:00 AM
FG, that's it.
Title: Re: Grains per inch ?
Post by: dbd870 on August 16, 2017, 09:03:00 AM
Yep, I never even look at gpi - all I care about is that the overall arrow weight is reasonable and it shoots well.
Title: Re: Grains per inch ?
Post by: smokin joe on August 16, 2017, 09:08:00 AM
The grains per inch of a shaft is useful in planning out your arrow construction if you have a desired total weight range for the finished arrow.

The grains per pound figure (total finished arrow weight divided by the pounds of draw of the bow) is important in calculating whether or not your finished arrow id too light or too heavy for the intended use.
Title: Re: Grains per inch ?
Post by: flyguysc on August 16, 2017, 09:12:00 AM
Yea its never been to much of a issue it's just that I'm going to the deer woods this year for the first time in a long time and wanted to make sure. Thanks