Theory to reality

[lucky strike]

I bare shafted 5 different bows -all modern -FF
2 BW recurves,7 lakes lng bow. green mt lng bow,blackhawk lng bow.(B-50)
All bows shot bareshaft perfectly!all are different poundages.All are different shafts.
The dynamic chart was used for theory and rechecked several times for correctness.The shelf cut being of most importance.
RESULTS---On all bows the correct dynamic spine was 18 to 20 lbs more than the bow called for to achieve perfect bare shaft flight.
So much for theory!

[lpcjon2]

Hey Joe I live near you by AC and work in Woodbine

[GINKSTER]

A little more than one would expect. I bet that 5 different bows would have different results. Very interesting.

[Orion]

Hmmmmm.  I've been overspining a lot of my woodies by as much as 15-20# for many years.  Never bare shafted, but they fly good.  Must be something to it.

[Oregon Okie]

curious. are you saying you used the dynamic spine calculator program or a chart of some other kind?
I have found the dynamic spine calculator to be closer than that... under less than scientific testing  

[Mint]

Stu's dynamic spine calculator for me has been spot on. A real lifesaver for my palmer recurve since I couldn't get arrows to fly out of it until I realized the dynamic spine was higher than what I was using. Came up with using GT 55/75 with a 50gr brass insert and 200 grs up front and they fly like darts. I do know your release can have a big impact on the spine of your arrow.

[Daddy Bear]

Guide charts do a pretty good job of ball park estimations to find a starting point when it comes to the tackle itself.  However, the human element of the equation may alter the ending results to a greater degree than the components.  Though you may be consistent in your technique, your technique may be off that of others as we are not machines.  You may find that one person finds better results with a different dynamic spine.  You may find that five different archers of varying skills may all have differing results when using the same bow.

[Don Stokes]

Daddy Bear, that fits with my experience. When in the arrow shaft business we created a chart that was based on bare-shaft testing, but the variation in individuals' form or bow setup made adjustments necessary much of the time.