Victory VAP 450 Weaker than expected spine

I use a Mathews Solo cam 53# I use Victory VAP 400 spine arrows 27 inch long with 125 grain tungsten point these tune fine at 40 yards they show the spine is slightly week 50mm right impact with bare shaft so I was quiet happy with the result.
I then decided to make up some light arrows for field target & 3D so I bought the same arrow make with 450 spine everything was the same except I put 80 grain points in the arrow.
I expected a arrow that was to stiff as the arrow chart says I require a 500 spine the bare shaft is impacting 150mm right at 20 yards showing it's far to weak
As anybody else had this experience or can explain why this has happened.
Would be good to get some ideas
 

Rik

Supporter
Supporter
Okay, so the recommendation is for 450s with a 125gr point, but you find 400s a little weak...? So it would imply that the recommendation of a 500 shaft, ought to imply that 450s with an 80 grain point will show a little weak, shouldn't it?
 
I agree that the 450 could be a little weak. I was prepared to accept that to get out a lighter arrow.
The fact it goes 150mm right at 20 yards means the spine is way off or there is another reason.
I also have a set of Easton Lightspeed arrows 500 spine 100 grain points 28 inch long I use for indoors the spine is spot on.
 

AndyW

Well-known member
brassgbits,
Are you shooting off fingers as that could explain arrows seeming a bit weak. The trouble with charts is that they are just a guide, for field it's nice to get a good bareshaft but not the be all and end of.
I happily sacrifice bareshaft for speed, as long as the fletched goes where you want. You can get too hung up on tuning, speed etc. I've been doing it for years, end of the day you will get more benefit from being out in the wood practicing than you will correcting a slight anomaly with bareshaft tuning or making up another set of arrows.
Just my 2p
 

Rik

Supporter
Supporter
I agree that the 450 could be a little weak. I was prepared to accept that to get out a lighter arrow.
The fact it goes 150mm right at 20 yards means the spine is way off or there is another reason.
I also have a set of Easton Lightspeed arrows 500 spine 100 grain points 28 inch long I use for indoors the spine is spot on.
Unfortunately "shaft number x from manufacturer y" working does not mean that "shaft number x from manufacturer z" will work, even if they say that the shaft number is supposed to correspond to something similar... the problem being that things like "spine" are only a proxy for the shaft match, not a direct measure of the match. That's why they all give their own charts, and why sometimes they don't work.
 

Cereleste

Supporter
Supporter
AIUK Saviour
The 400 spine was already slightly weak for you, and you then switched to an even weaker spine with the 450. Changing the point weight doesn't have a large effect on spine especially when the shank is changing length also and is generally only useful in borderline cases and it's more about trial and error than anything rigorous. With break-off points on my recurve, I barely notice the difference in tune when removing sections because the stiffening effect of the reduced point mass is somewhat cancelled out by the increased length over which the arrow can bend freely, but switching from a short shank 100gn point (120gn with two sections removed) to a long 100gn point (100-90-80 no sections removed) makes a large difference in the frequency at which the arrow bends. Your tungsten points likely have a similar shank length to the 80gn steel points so one would expect to see both a small dynamic stiffening effect from the lighter point mass and a slight stiffening or weakening effect depending on which shank is longer.
If you can swap the points between the two sets, does that make the 400s slightly stiff and the 450s not much weaker? 400s with the 80 grain points would only be 11 grains heavier than the 450s.
 
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