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Discussion Starter · #1 ·
To find the correct arrow length and spine combination I went off of eastons spine chart to get the correct spine. Starting with arrows a little long to trim down. I fletched one shaft and and kept another bareshaft. Bow is tuned and shooting bullet holes through paper. I sighted in fletched shaft at 20 yards and shot the bareshaft 2nd. Fletched was in target perfectly straight and bareshaft with 100gn field point and it was in the target perfectly straight as well. Hearing that a weak spine bareshaft will sit in the target nock left I decided to put more weight up front to weaken the spine for testing. I put a 200gn field point on the bareshaft and the arrow was consistently sitting in the target nock right. The result was the exact opposite of what I thought it was supposed to be. Can anyone explain the physics of this to me?
 

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To find the correct arrow length and spine combination I went off of eastons spine chart to get the correct spine. Starting with arrows a little long to trim down. I fletched one shaft and and kept another bareshaft. Bow is tuned and shooting bullet holes through paper. I sighted in fletched shaft at 20 yards and shot the bareshaft 2nd. Fletched was in target perfectly straight and bareshaft with 100gn field point and it was in the target perfectly straight as well. Hearing that a weak spine bareshaft will sit in the target nock left I decided to put more weight up front to weaken the spine for testing. I put a 200gn field point on the bareshaft and the arrow was consistently sitting in the target nock right. The result was the exact opposite of what I thought it was supposed to be. Can anyone explain the physics of this to me?
IF you are shooting a COMPOUND bow with a RELEASE
you are confusing STIFF spine and WEAK spine, with shooting a RECURVE with fingers or shooting a COMPOUND with fingers.

For a RIGHT handed FINGERS shooter (FINGERS recurve or FINGERS compound),
if the point weight is too low, you get a STIFF reaction for a FINGERS shooter (recurve or compound)
and this would be a NOCK RIGHT thru a paper tuner, and at 20 yards the bareshafts will miss WAY LEFT of the fletched group.

For a RIGHT handed FINGERS shooter (FINGERS recurve or FINGERS compound),
if the point weight is too high, you get a WEAK reaction for a FINGERS shooter (recurve or compound)
and this would be a NOCK LEFT thru a paper tuner, and at 20 yards, the bareshafts will miss way RIGHT of the fletched group.

For a COMPOUND RELEASE shooter,
if 100 grains is PROPER SPINE...the arrow group will be nice and tight.



Fletched AND bareshaft.



Three Fletched.

Shooting COMPOUND with a release.

So, what happens if you put a 200 grain field point, instead of the 100 grain field point, SAME arrows?
What does a WEAK reaction look like, for a compound RELEASE shooter?
When the point weight goes DOUBLE for what "proper spine" dictates, the arrows go WOBBLY,
and the group size EXPLODES larger.



Left nock tear (right handed shooter) is a draw length problem.



When the shooter is leaning WAY WAY Back, and trying to shoot a 1-inch TOO LONG draw length,
when the shooter is trying to shoot a 2-inch TOO LONG draw length,
the right elbow goes TOO far behind the head, and you can see WHY this shooter will get a MASSIVE nock LEFT tear.

Has nothing to do with SPINE too weak or SPINE too stiff.




GREEN hat shooter will get a massive NOCK RIGHT tear.
Has NOTHING to do with arrow spine.
Has everything to do with the shooter's FORM, cuz he is pulling the bowstring HARD to the RIGHT,
and this pulls the bowstring HARD to the right
and when a shooter pulls the bowstring HARD RIGHT,
the nock RIPS the paper tuner with a RIGHT tear.
 

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Discussion Starter · #3 ·
@nuts&bolts I am a right handed shooter with a compound and release. Draw length fits perfect. So is a weak spine bareshaft supposed to miss left and be nock right, and is a stiff spine supposed to miss right and be nock left? Is this the same for a left handed shooter? also do you have a list or chart of this?

Thanks for the great answer.
 
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