SelfBow Questions

[bigcountry]

Do selfbows lose thier zip over the first 20-30 arrows shot?  Here's my scenerio.  I have a 48# osage selfbow.  I am trying to find the right spine for POC's.  I was told by Paul Jolin from elite archery to shoot thru paper at 3-5 yards depending on centershot.  I usually am a broadhead plane tuner or bareshaft.  

Ok, so my first 10-12 arrows, everything looks good, I find bullet holes from 47-50# spined cedars.  I get weak reactions from 43#, I get pretty good tears from 45, 47, and 50, with 50 showing slightly stiff. And 52 definatley nock right stiff.

After 20 arrows, things change.  50# spines now start tears like low nock, and so does 52#.  45-47 start showing stiff.  43# look better.

I have repeated this for 3 nights

Are osage bows dynamic?  Do they lose springiness over a shooting session?  Right now, I want to order a dozen and leaning towards 45# spine.  


I wish I had some bare shafts, as I think I can see more what is happening.

[John Scifres]

They shouldn't.  But definitely go with the spine that shoots best the first few arrows.  My selfbows generally like 5-10 pound less weight in spine.  I shoot 27" though.  Are you sure you aren't getting tired and short drawing?

[bigcountry]

Yea, I am pretty sure I am getting to full draw.  I made a very large effort to make sure last night everything was consistent.

[tom sawyer]

I believe that in the old days tournament archers used to unstring their bows in between ends.  This suggests to me that there is at least some slight change in performance.

The other observation I would supply, is that a bow's side profile is different just after unstringing, from where it started prior to stringing.  It will return to the pre-strung position, but its the just-unstrung position that is what you are dealing with when shooting.  The reduced reflex, meaning you are getting slightly less early weight on the draw.

I would personally test the bow after it had been strung awhile, in order to get the right spine for a hunting situation where you are going to have the bow strung.

[bigcountry]

I am going to try it again tonight but this time take BH measurments and poundage at my draw.  Kinda interesting.

[BigArcher]

The old time target shooters would unstring their bows between ends to keep the bows shooting the same, I have been told.
So they probably do lose a touch of cast after a few arrows.  I don't chronograph so can't say for certain.  I do find more problems finding the right arrows for light bows. 50 or less.  The tiller is that much more important and the proper arrows seem too small.
I agree that normally 10# less spine can be a good starting point for finding the right arrow.
Also try lighter points.
good luck and have fun.

BigArcher

[Shaun]

I can't believe you are seeing much diference between 5-10 lb spine spread. More likely your form and release affecting arrow flight. Self bows vary in how much they hold their cast when strung. Bow legth, wood stability and moisture content, overstress from tillering, etc.

Some lose noticeable cast after being strung and shot for a short time, some seem unaffected. I think I subconsciously adjust by pulling the some draw weight - not the same draw length - as the bow becomes softer.

Bare shafts are the best way to go, but you can surely see if your arrow is flying really well. Its just harder to zero in on what spine / lenght / point weight combo makes good flight.

For an average 48 @ 28 osage self bow you will most likely end up shooting 40/45 spine if you cut your arrows around 28.5" back of the point and shoot 125 grn heads.

[Jack Skinner]

You might try backing off from your paper a bit more. Paradox from a selfbow is much more than any trad bow. Give the arrow a little more time to recover. A selfbow has a lot of handle. With release and paradox and what not I back off from paper testing right up close. Maybe 8 to 10yds. These are usually my closest shots anyway.

I have never had a selfbow I have built stop shooting my spine weight arrows well. Meaning I build all my bows to the same 5lb draw range (55-60), and they all shoot my 50-55 spine arrows cut to 29" for 160gr or 28" for 190gr just fine.

[Eric Krewson]

The first few shots from my personal bow shoots 55-60s or 50-55s equally well. After about 30 shots it settles into the 50-55s and the 55-60s are hitting a little left. After being strung for 8 hrs or so and a couple hundred shots I can detect a slight loss of performance but not enough to overspine my 50-55 arrows.

[bigcountry]

Thanks Eric.  Thats kinds what I am seeing.

[bigcountry]

After shooting again last night, I just decided to meet in the middle.  50# work great for first 10-20 shots, but after that 45# fly great.  So I ordered from Paul Jolin 44-47#.  split the difference.  

wierd thing is last night, my BH nor poundage is not changing.