A Question?

[Bruce]

I am currently shooting a size 400 doo sung at 29.5" with a 108 gn point .

If I went to a size 500 doo sung at 28.5 " What point weight would I Require to match the spine of the 400??

I wish to do this excercise to look at getting more speed for unmarked .


Thanks in anticipation


Bruce

[2Dogs]

Bruce,

I don't think it could be done. Been playing with Archers Advantage and to change static spine you would have to drop to a 40gr point ....almost...maybe lighter.

The 400 is like a 430 and the 500 is like a 520, I don't think a point weight adjustment would accomdate the difference in spine.

My 2c's worth :wink:

[James Park]

Bruce,
Not a simple question. However, some comments:
- The resonant frequency of a 500 is lower than a 400 (for a given point weight). Hence, for a given arrow length it suits a slower bow (for example, a lower draw weight).
- Lowering the point weight will raise the resonant frequency, however it does not raise it by much.
- Since the 500 will be lighter than the 400, you require a higher resonant frequency for the 500 than for the 400 when shot from the same bow.
- My estimate is that even with a very low point weight it will not have a high enough resonant frequency to get the same tuning characteristics.
- However, my experience is that the lighter arrow will still work satisfactorily and give launcher clearance (whereas going to a stiffer arrow may not).
- Consequently, I would try something around 90 grains (just to pick a number out of the air). I use 90 grains on my 520 ACE's.

[Bruce]

Figured that might be the case.

Might have to look at another brand of arrow for some speed.

Mainly for aba and 3d

How are those cheetahs going and who do you get them from


Is it Mr Reeks

[2Dogs]

Cheetahs are going very well. Archery Supplies in Canberra sell them.

My 400's weigh 306grain made up, with 90gr points......damm fast for that stiffness arrow.

Jim,

Interesting about the weaker arrows. I always used 1 size less then what the arrow charts recommended. I've got 500 & 400 Olympians. The 400's are supposed to be theortically a closer match to my setup.

But the 500's come out of my bow damm straight, fast and group just as good as my 400's. I Do get better arrow flight out of the 500's.

I'm thinking of going back to my 500's....maybe I'm getting just that little bit better clearence

[James Park]

Paul,
I agree. I usually select one size lighter than the chart for exactly that reason. Always found it to work well.
Definitely had clearance problems when I have gone one size too heavy - not worth the hassles.

[Eberbachl]

Hey Bruce, my Safaris (read carbon aeros, or Beman ICS) are 303gn with an ACC hyperpseed 90gn point, uni bush and G-nock, they are doing around 293FPS out of the CyberTec. I'm using the 45-60 safaris and shooting 60lbs......

[OldDog]

With you on this one Paul, theory says the 400 should be my arrow but the 500 flies and groups really well :)

[Eberbachl]

With you all (Paul, James, and Noel) on this one.....that's why I'm shooting the 45-60 Safaris....the weakest spine, but flies And groups very well at 60lbs with good clearance on a golden key premier rrest.....