Main Discussion Area > Arrows
10 gpp?
Nidhoggr:
I meant GPP. GPI is "grains per inch". Been making arrows today and calculating their GPI so i keep derping and typing it by mistake.
willie:
So how does one find that sweet spot GPP for any particular poundage?
upstatenybowyer:
These are great answers! I'm totally glued in. Keep um comin'! (-P
Nidhoggr:
--- Quote from: willie on January 06, 2018, 02:32:10 pm ---So how does one find that sweet spot GPP for any particular poundage?
--- End quote ---
Testing. Rule of thumb though as stated is 10 GPP. Has a good amount of speed and power at that ratio. So a 60# bow would do fine with a 600 grain arrow, where as a 50# bow would do decent (12 GPP), and a 30# bow would probably do very poorly with it (20 gpp).
Keep in mind though: GPP is not the only concern. There's also arrow length compared to your draw length, the spine of the arrow, the straightness of the arrow. Every wood weighs different and will behave different. My oak 3/8D" 24L" are faster than my 3/8D" 24L" poplar arrows due to being lighter but I get much better performance out of the poplar due to it having a better spine and more GPI. Oak are less durable as well compared to poplar.
So there is no "magic formula" for arrows. I shoot at a 27" draw on my recurve but do a 24" on my long bow (don't know why) and I cannot interchange the arrows very effectively. My long bow HATES 5/16D" poplar @ 24L", but my recurve loves 29L" 5/16D" poplar and fires the 24L" fine as well.
My typical arrows with my 55# @ 28" recurve are 5/16D" poplar cut to 29L" with a 125gr field point and 4" shield cut feathers. My 50# @ 28" long bow uses 3/8D" poplar 25L" with 100gr field points and 4" parabolic cut feathers.
So.... yeah lol. Basically: 10gpp is the ideal zone to be in, but not the only factor. As people have said: you WANT target arrows to be lighter (6 - 9 gpp) because they are straighter shots on target. You want a hunting arrow to be heavier so it has more momentum and kinetic force (10 - 13gpp).
--- Quote from: upstatenybowyer on January 06, 2018, 02:46:34 pm ---
These are great answers! I'm totally glued in. Keep um comin'! (-P
--- End quote ---
Not sure if serious lol.
upstatenybowyer:
I'm very serious Nidhoggr, you know a ton about this stuff and I know zilch, so I really appreciate your insight! :OK
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