Brass inserts and tuning

[Ari_Bonn]

Quick question.  Not an issue with standard gold tip inserts but I am thinking of making up some up with a 100gr brass insert and I am thinking to myself that is alot longer.  So... When using say the 3rivers chart ( I find it has always worked well for me)

Do I use the back of the insert as my back of point measurement? I can't imagine the arrow is going to flex with what is a footing of sorts.

[The Whittler]

Not quite sure if this is what you want. If your shooting an arrow with 225gr point and you switch to a 100gr insert with a 125gr point you should be able to use the same arrow length.

If you want to use a 100gr insert with the same point weight you are useing now then you will have to change your arrows to stiffer. Or if you can cut enough off the arrows you are useing now.  Hope this helps.

[Gdpolk]

I've not noticed the additional length of the heavier inserts to significantly change point of impact on the basis of them acting as an internal footing.  I just got done testing this among other things.

For my particular bow/arrows, I have two arrow builds with just north of 225gr total weight up front:  

• My stumping/target/small game arrows are being shot with a 100gr insert, 8gr aluminum footing cut to length of insert, and 125gr heads.
  
• My broadhead specific arrows are built with a standard 12gr Gold Tip insert, no external footing, and 225gr broadheads.  (This puts my total broached point weights of all of my arrows within <5gr of each other which is close enough.)
  

From my testing, I get the same point of impact out to 40 yards (longest distance I have to shoot) with the following varied arrow builds using full length GT Traditionals with a combined point/insert/footing weight of ~235gr:  

• Fletched shaft, 100gr insert, 125 gr field point
  
• Fletched shaft, 100gr insert, 125 gr broadhead
  
• Bare shaft, 100gr insert, 125 gr field point
  
• Fletched shaft, 100gr insert, 125gr RFA Talon/screw in rubber blunt/Judo point
  
• Fletched shaft, standard insert, 225 gr field point
  
• Fletched shaft, standard insert, 225 gr broadhead
  
• Bare shaft, standard insert, 225 gr field point
  

 Therefore, based off of my tests, I've concluded that from my bow with a well tuned Gold Tip Traditional arrow as long as the overall point weight is equivalent and the shaft length is equivalent then the differences in weight distribution of points vs inserts, head length, head type, and insert length are negligible.

[memo]

It will flex fine. The arrow will flex in the centre of the shaft, not behind the head

[Roadkill]

If the static center of the shaft is,in fact, center, where is the dynamic center of the shaft when loosed if it is forward weighted considerably?  Does the arrow shaft flex the same? I turn to the experts for that.
GD,your test is exactly what I would expect: you really only tampered with the business end of the shot.  You could change the dynamic spine in a variety of ways including point weights.  Sounds like your setup is spot on