bare shaft tuning

Munsterman

Active member
Hi,

Never shot a bare shaft arrow before this evening, but on a whim decided to give it a go while shooting fletched arrows at 60 yds. To my amazement the bareshafts missed the target 9 out of 10 times and only barely made it on at 10 o clock in the outer white the 10th shot. The bareshaft always flew left of the grouping.

I moved to the 20 yds and 30 yds targets, to get more info. At 20yds 10 out of 10 bareshaft shots impacted approx. 4-6 inches high and approx 15-18 inches left of the of the grouping (shooting into a varying breeze medium light breeze too too). Even worse at 30 yds.

The walk back test to 60 yds could not be much better so never bothered with bareshaft shooting until now. Our club elders always discounted the need to do the bareshaft tests, and enthusiastically advocate the walk backs.

I am left handed, so I believe that the results indicate a weak shaft. correct? Given the large discrepancies between the bare/fletched arrows, am I likely to be able to use the button to get them to converge to an acceptable level?

M arrows are approx 1/2 inch too long so will probably have them shortened, which will stiffe them a bit, but am I better off biting the bulet and buying a stiffer shaft?

I currently shoot Nav 540/ 30 inches/40 pounds G3 with Helix riser (hence why arrows are a little long now)

best wishes,

Colin
 

JohnK

Well-known member
Bare shafts left for a left-handed archer - yes, that's reading weak.

However, before you do anything else, you should work on that nocking point. Nocking point height can affect the vertical impact too, so go to 20 yards or maybe 30 and tweak the nocking point up until the bare shaft reading comes level with the fletched group.

One other thing - are you shooting more than one bareshaft? It's important to shoot two or three at least, just in case there's something wrong with one of them.

And try to shoot in calm weather, if you can :D
 

PaulT

The American
Ironman
American Shoot
Yes GGC, that does indicate a weak shaft and also a low knocking point.
Sort the knocking point out first and then if the bare shafts are still the same laterally try shortening the arrows. You will be surprised by how much difference it can make. Only go for the new arrows then if you still need to - no point throwing money away if you don't need to.
 

Big Boy Blue

New member
Fonz Awardee
Ironman
Whats interesting is that the 2006 Easton shaft selector program recomends a 610 spine for the Nav, which would be even weaker.

Putting the figures into Archers advantage it suggests that the 540 spine is a bit stiff.

You have mentioned a weight of 40lb, is this the limb weight or the weight your holding on the fingers ?

The nocking point most certainly needs adjustment.
 

Munsterman

Active member
Big Boy Blue said:
Whats interesting is that the 2006 Easton shaft selector program recomends a 610 spine for the Nav, which would be even weaker.

Putting the figures into Archers advantage it suggests that the 540 spine is a bit stiff.

You have mentioned a weight of 40lb, is this the limb weight or the weight your holding on the fingers ?

The nocking point most certainly needs adjustment.

Hi,

Thanks - The limbs are 40lbs at 28 inches as marked. My draw is closer to 30 inches. last time I measured the weight on the fingers it varied from 44 to 47 lbs depending on the bow scales used.

I will look at shortening the arrows by approx 0.5 inches. Would that change the spine very much? How about the point weight? I have 110 grain points fitted on the 540s. Is it worth consdering dropping to 100grains?

By the way I have used 3 baresafts and all give the same results.

Colin
 

Big Boy Blue

New member
Fonz Awardee
Ironman
GingerGeneCarrier said:
Hi,

Thanks - The limbs are 40lbs at 28 inches as marked. My draw is closer to 30 inches. last time I measured the weight on the fingers it varied from 44 to 47 lbs depending on the bow scales used.

I will look at shortening the arrows by approx 0.5 inches. Would that change the spine very much? How about the point weight? I have 110 grain points fitted on the 540s. Is it worth consdering dropping to 100grains?

By the way I have used 3 baresafts and all give the same results.

Colin
Bow scales need to be calibrated. I used a 25l container and started to add water to give me the correct poundage. Then I just plotted weight against scale reading. Mine always reads 4lb high.

Dropping point weight will stiffen the arrow a small amount but you will get more stiffening by reducing the arrow length 0.5" This assumes that you can stiffen them enough

You can also stiffen an arrow by adding weight to the string or increasing the brace height, anything that reduces the energy transferred to the arrow.

Bottom line is you may need to be looking at new arrows
 

Shirt

Well-known member
No, you're screwed. Half an inch and ten grains won't get anywhere near. You need new arrows, something around a 450-430 spine. You can get a 430 in either Navigators or ACEs depending on which you've got the cash for.

Either that or drop about 6# in draw weight.
 

Munsterman

Active member
Shirt said:
No, you're screwed. Half an inch and ten grains won't get anywhere near. You need new arrows, something around a 450-430 spine. You can get a 430 in either Navigators or ACEs depending on which you've got the cash for.

Either that or drop about 6# in draw weight.
Thanks to all,

I guess its new shafts for me then. May buy them in USA next week. Wont have my bow with me so may have wait until I return. Hmmmm, Decisions, Decisions!
 

Munsterman

Active member
Nobody in our club shoots arrows any stiffer than Nav 540s. I think that perris Archery do a "try an arrow" scheme. Works out more expensive but may be worth it if I can try various spines.
 

jerryRTD

Well-known member
I checked the easton spine selector it is difficult to get any where with out a proper draw weight. you can add two pound per inch but that can be just an approximation. If you are worried I would go for the try an arrow scheme. It might be more expensive but not as much as buying the wrong arrows.
 

SLOWHAND

New member
Thats a hell of a draw weight you're pulling, i assume you haven't been shooting for very long. Are you fully relaxed and comfortable with the weight. Could you shoot 150 arrows at this weight and be as accurate with the last arrow as with the first. If the answer to any of these is no, then a new set of lower poundage limbs would be more of an advantage than a new set of arrows.
 

Munsterman

Active member
SLOWHAND said:
Thats a hell of a draw weight you're pulling, i assume you haven't been shooting for very long. Are you fully relaxed and comfortable with the weight. Could you shoot 150 arrows at this weight and be as accurate with the last arrow as with the first. If the answer to any of these is no, then a new set of lower poundage limbs would be more of an advantage than a new set of arrows.
Yes, it does seem a lot but I have become quite comfortable with it and my draw length is maybe quite average. I have done a lot of gym work prior to taking up archery, so my back arms and shoulders are quite strong. I guess a lifetime of swimming helps too. Coincidentally, I have shot that number of arrows in practice without a discernible difference in performance, other the pattern I have always observed even with my old and lower poundage bows i.e approx. 5-10 percent lower scores in moving to shorter distances. Actually works that way whether I move from 50 to 60 or vice versa. Convinced this is a psychological thing
 
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