Sitka Mountain Gear
Same spine different weight?
Contributors to this thread:
hoyt-6190 14-May-19
GF 14-May-19
elkstabber 14-May-19
ELKMAN 14-May-19
ohiohunter 14-May-19
Shawn 14-May-19
hoyt-6190 14-May-19
12yards 14-May-19
x-man 14-May-19
From: hoyt-6190
So my bow is tuned to shoot Easton FMJ 5mm 340 arrows at 11.3 grains per inch. Would tune change if I shoot say a Easton Axis 340 at 9.4 gpi? Is the spine what matters or is the gpi play much of a factor in determining the tune? I understand I would have to resight the bow in, just wondering if tune would be the same as they have the same spine and o.d.

From: GF
On a recurve or a longbow, it would change a BUNCH.

I’m going to guess that you will end up way too stiff, though maybe with a drop-away rest, etc you could swing it.

I would just re-tune from the ground up.

From: elkstabber
The tune will be different because your arrow will be leaving the bow at a faster speed. This is assuming that you're using the same fletching, insert, point, etc on both arrows. The lighterweight Axis shaft will need a stiffer dynamic spine (cut shaft shorter or maybe use a lighter point weight). Or, most likely, you may not find it to be noticeable at all.

No it shouldn't if you cut same length and use same point weight. But you will obviously need to change your sighting down range.

From: ohiohunter
If there is a difference, it will be minimal. In all reality if you're bow is "tuned" now then all it will take is 10min in front of some paper to fine tune as needed, you certainly should not be twisting yokes and timing cams.

From: Shawn
No you will have to change your sight but spine is spine. I have gone from 9.4 gpi to 7.4 gpi and only had to change my sight a very small bit. Shawn

From: hoyt-6190
I figured sights will obviously move cause of the velocity difference. I just wasn’t quite sure if two arrows with same spine, same o.d., same manufacturer but different gpi would cause a change

It might change very slightly if anything... Easy to check with a couple bare shaft shots at 10 and 20 yrds.. and if you're already paper tuned and the diameter of both arrows are 5mm, there should not be much difference if any

From: 12yards
I don't notice much difference when shooting my Camo Beman ICS Hunters 340 spine (10 gpi) vs. my GT XT Hunters 340 spine at 8.9 gpi.

From: x-man
All else equal, it will not change your tune on a modern compound bow.

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