Guru Question - Help

[BT]

Here is the deal.....I have the Black Swan and just finished shooting it with some good/poor results.
Good results are that I am dead on with this bow....bad thing is that I am dead on to the left of perfect

2016 shafts are not the ticket

I finally worked to a 2213 @ 28" with a 150gr. head and that gave a consistent 2" left of point of aim.

Changing to 175gr. heads that distance closed to 1"

Since my natural point of aim is 2" right I want to maintain that , rather than having to retrain my brain to shoot more right.

I want to stay with the 150 grain heads but it looks like 200 grain are what a 28" 2213 needs (for me)

I need some combo idea's based off this current set up and my desire to get another 1-2" to the right with the impact.

I could go to a 2115 or a 30" 2213 with the 150grain head (I think) but before I start cutting and experimenting I am looking for some educated opinions on my next move

[Greg Krause]

are you using a rest? or off the shelf?

I need to know your set up before i can fully answer any queastions

[BT]

Yeah
Off the shelf .... SMJ was right , it's great....so far.
I just ordered a dozen Interceptor in 190 grain just because you never know what will happen with the Simmons company now that they are for sale.
Maybe I will keep those for the piggies




Maybe not

[Greg Krause]

How think is the striker plate/pad on the side of the window? changing the thickness of that may allow you to change POI

either that or change anchors! I brought mine a little lower and more to the front of my face, now I am POA

[smj]

I agree with the shelf or rest question above from skip and would add to it - is this bow a center shot???

It sounds like you are a bit stiff (the arrow shaft that is!) and maybe not a true center shot. I don't know the bow. Still, from what you've presented, it reminds me of one of my longbows...

A longer shaft, or one with a bit less spine sounds like the right thought on the situation. If you have a good release, my finding is that you can shoot a shaft that is a little to stiff and still get reasonable flight with it. However, unless it is being shot through the center of the bow, the more stiff the arrow the more it will kick left - assuming right hand shooting. The idea of course comes back to the archers paradox! Both a center shot and a shelf out on the edge of the grip will shoot the same (right/left) if the arrow is spined right for the bow. The arrow will flex around the grip of the non-center shot bow and be delivered down range with correct right/left line-up. If the arrow is a bit stiff, it will bounce off the grip a bit. Hence, for a right hand shooter the arrow gets tossed to the left, for a south-paw the arrow will bounce right. How much bounce happens depends on the distance the rest is from the center of the bow tip to tip, and also on how stiff the arrows spine is. Once you have an arrow close to the correct spine, then you adjust shaft length and tip mass to effectively reduce the arrow spine. Longer length allows for more flex in the shaft for a given amount of stress. A heavier tip creates more flex by presenting more load to the tip of the shaft during a given stress. Either way, this additional flex allows for more clearance at the time of the shot. This has been filmed and proven before. If I can find a clip on it, I'll post the path. With a typical compound manufactured today, the bow is designed to allow a center shot. Add a drop-away rest and stiff arrows with light weight tips rock! There is nothing to flex around, nothing to disturb the shot if the string does not pull up or down on the tip. If the bow kicks the arrow, then you'd have to tweak out the arrow/bow system.

I have two shafts for a longbow, ~55 pounds at 31" draw, not a true center shot. I currently shoot a Goldtip Tradition 5575 at full length. After smoothing out my release, I can get these to fly really well only by going to a 145 grain tip. They shoot left for me, but fly well. I went with this arrow for the over-all arrow weight. I should probably go to a 175 or 200 grain tip to get away from shooting to the left. I don't go to the heavier tip because the arrow weight would go up to over 550 grains, and they'd drop like rocks to the point I'd not have as much fun shooting them. They are marginal as is, but kind of OK out to 30 yards. The other shaft is the Carbon Express Heritage 350, also at full length. I don't think I could put enough tip on them to get these to shoot right. They kick left, and wallow, and drop like rocks. They weigh more and are a lot more stiff. Not worth messing with - but they are nice heavy shafts! I am thinking that the Goldtip Traditional 3555 might be the right arrow. However, I worry about what tip weight I'd end up with and what the over-all arrow weight would be. Once I get employed again, I'll buy three shafts and see how it works out. I also intend to build a 70 pound bow and hope that the 350's work with it! (They are nice shafts!)

You might check out the following chart -
www.eastonarchery.com/spineWeight/hunting/

Note - I see a 2013 and a 2215, but not a 2213... Also, if you drop back one selection and drop the hunting - change to target, you will get the target shaft results. Move the mouse from dot to dot on the graph to get the details of a given shaft.

It shows the deflection of a 29 inch shaft supported at 28 inches for a given mass. There are a collection of shafts to look at, the deflection represents relative shaft stiffness. This allows you to make general comparisons among shafts. I have not spent the time to understand how much additional deflection of the shaft relates to say a 25 grain change in tip weight - yet I believe it could be done without to much effort... I should probably do that! This might help with the understanding of what needs to be done to tune the shaft to the bow.

Don't know that this answers your question 100%, but I hope it is a start!

[smj]

skipmaster1 said:

How think is the striker plate/pad on the side of the window? changing the thickness of that may allow you to change POI

either that or change anchors! I brought mine a little lower and more to the front of my face, now I am POA

Changing the anchor point this way changes two things that I don't like a whole lot.
In this case -
1 - reduces draw length which means a stiff arrow should actually appear more stiff due to a reduction in draw weight.
2 - Changes the way you look down the shaft - which will effectively move the impact point of the arrow at the target, without changing the tune of the arrow, possibly even allowing for a greater mis-match than you had originally due to the load reduction due to the reduced draw length.

Changing the thickness of the pad on the riser will allow your arrow to get more close to a center shot, or further away if made thicker! This allows for more or less bounce away from the riser, depending on right hand or left.

[smj]

Here's a couple posts to look at -

Slow-mo of the arrow flex on shooting:
www.youtube.com/watch?v=aNI9BG87qcI

So what happens when the spine is to weak?
youtube.com/watch?v=G1Kj6X_AcbU

Over-all info -
www.meta-synthesis.com/archery/archery.html

[BT]

I generally have been getting the best flight with a 31" arrow out of my previous bow and this bow is darn near identical as to the center shot.
It's very close to center shot but not a center shot.
I have a 1/32" leather plate on the riser so decreasing that isn't an option.

The 2213 shaft @ 31" always seems to give the best flight with bows that are 60# but I wanted to get that length down if I could.

The 175gr. actually didn't effect my 20 yard impact all that much...maybe an inch .....I was really surprised and assume it's the bows efficiency that is giving me the ability to maintain with this high F.O.C. while maintaining good arrow flight dynamics

Increasing the paradox is the only way but I dont want to gain a fishtail while attempting to correct the line of sight/point of impact.
That was the crux of the question....what direction would you start off on?
Would you correct with head weight , shaft length or shaft change?.
It seems that you tend to follow shaft length .... correct?

[smj]

On the quick here, I'll give this a bit more thought today, but I like to pick a shaft length and stay with it. I also like longer shafts, but I have a long draw, 31 inches. My thought would be if you can increase tip weight and keep the current shaft, without exceeding the over-all arrow mass you want to shoot with - you are good to go. If by increasing the tip weight you end up with an arrow that exceeds your weight goal, time for a new shaft. Again, I like arrows a bit stiff and adjusted with the tip weight rather than purely by adjusting length. More later, my wife is reminding me that I need to focus on the turkey to be cooked!

[BT]

LOL! .... the house is definitely a priority today
That's what I was hoping to do....adjust spine while maintaining a set length....not sure that I am going to be able to do just that.
Ideally , I would like a 29" shaft for my 27 1/2" anchor with the recurve but I dont know as I will be able to do that with a 2213 unless I really boost the head weight.
I dont see how I can exceed 10GPP @ 62#
I am currently in the ball park of 540 grains with the 150 head.

Thanks for the insight....I appreciate your consideration and in depth analyses