Another spine ?

[87TT]

If I use an insert that is 2" long, does that have the effect of a shorter shaft on spine?

 

[Mighty Mouse]

Yes, a longer insert will stiffen dynamic spine, but I've never seen any good info on how much. I heard Bill from Iron Will say on a recent podcast (Kifarucast or Lethal Podcast, can't remember which) that the stiffening effect of a longer insert/collar is minimal.

 

[87TT]

Kind of on the bubble so anything might help. Thanks

 

[Rob5589]

All I have seen is yes, it will stiffen the spine. How much is never really quantified. I couldn't imagine it being too significant being that it is so close to the end of the shaft.

 

[Billy Goat]

It's basically a footer, but hard to put a number on it. It seems to me to be around half the difference. So say your standard insert is 1", yours is 2". It's like shortening your shaft a half inch. Not much. I notice it with trad bows, not with compounds.

 

[87TT]

Grasping I guess. Right now I'm under spined a little. I don't really want to change my BH as I have a few and like them. I have my total weight at close to 500 gr. I have like 18 or so arrows. They seem to fly as good as I can shoot them. Group the FP and BH together pretty well. Just always trying to get better. I have some arrows without the inserts in. I may hot glue some standard inserts in a couple instead of the 50 gr and see if I can see an improvement. By dropping the 35 grs or so I should be i the range for the spine I have.

 

[roosiebull]

it does, but very minimally. i tried to stiffen the spine of some arrows a couple ways, using a HIT rather than a half out in a 5mm shaft, and a long 200gr stainless insert vs a heavy head in some standard diameter shafts... you could see a difference, but not a meaningful one. if you can, you are better off stripping the fletchings and cutting down a half inch then re-fletching, that will have more effect... i know it's a pain, but it's a good chance to try some different fletchings, haha. you can add weight to the back as well if not concerned about foc.... there are options, just no perfect ones.

the ones you don't have inserts in you could cut down before adding inserts if you aren't already as short as you can cut

 

[Marble]

I would try to cut them shorter. If you can...

I listened to the podcast also and had the impression it wouldn't make the difference in going from one spine to another or really at all.

I used to be of the opinion I wanted my BH of past my riser but have since changed that. It sits right square in the middle of a my riser.

You know your archery stuff pretty dang well. So in the back of your mind, you probably know what you need to do. I had a dozen arrows that I built not taking into account what point weight does to spine. Just dumb...I still have them but they sit in my squirl arrow holder. I use them for all my practice shots during season just to make some shots.

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[87TT]

If I reduce my point/head weight by using a regular 10 gr? insert instead of the 50 gr as a test. would that accomplish the same thing as shortening the shaft? Albeit lowering my FOC. I would do this as a test to see if it tightens my groups. This would be the easiest for me now as I don't have a saw or lighter heads. I could also check to see if my BH and FPs shoot together.

 

[Zac]

If I reduce my point/head weight by using a regular 10 gr? insert instead of the 50 gr as a test. would that accomplish the same thing as shortening the shaft? Albeit lowering my FOC. I would do this as a test to see if it tightens my groups. This would be the easiest for me now as I don't have a saw or lighter heads. I could also check to see if my BH and FPs shoot together.

Yes that would work nicely. Another option is backing out your limb bolts a quarter turn until your groups tighten. However your post above sounds like everything is solid. Why do you think you are underspined?

 

[87TT]

Looking at the spine chart. I have 30 inch arrows with 125 head and 50 gr insert with 69 or so draw weight. Currently Gold tip Hunter Pro 300s. Their chart and calculator only go up to point weight of 150 lbs (head plus insert) I’m at 175. Looks like I should be at 250 spine. They don’t make a Hunter Pro 250. Just thought I might try to stiffen up and see if my grouping improves then make a permanent decision on a course of action.

 

[Billy Goat]

Is that the aluminum 50 gr gold tip insert? The one that's about 2.5" long?

I think it allows you to shoot same length shaft as the standard insert, or very close.

Looking at charts increasing point weight by 25 grains is like adding 3# of draw weight. So if the max point weight shown is 150 but you are 175, just add 3# draw weight.


Generally you are going to group better with a weaker spine, especially at distance. It's a matter of finding a setup that is stiff enough to tune a broadhead, yet still forgiving.

 

[Marble]

I'm sure there is someone here that can run some possibilities with archers advantage and check what the shorter arrow does vs the lighter arrow. I suspect the point weight will have a bigger impact.

I was faced with something very similar and I would have had to cut my arrows to 26"...to get where I needed to be. I ended up just getting 300s. They work great.

It yours DL that's putting you on the bubble. If you do have to go to 260s, you always have the option of adding some twists to your cable and getting a few extra pounds.

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[87TT]

The BHs were flying like darts and hitting with the FPs with the Kudupoints. I shot them as well as FP out to 80. Sometimes I think it's just me and form issues as much as anything. Just always trying to fine tune stuff About time for a string change on two of my bows. Just waiting for the snow to melt off and warmer weather. My paper tune set up is behind my RV in the shop so I have to be able to pull it out. Think I'll wait a couple weeks and change the strings before i try any arrow changes.
Still shooting everyday in the snow out to 70. Do have a couple arrows waiting for the snow to melt for me to find. Don't you hate it when you forget to dial the sight back when you shoot at shorter ranges?