Bareshaft Voodoo ?

[mrjsl]

Ok, after hours of reading on here for over a year, and studying stu miller's spine thing, and shooting a zillion arrows I've arrived at a conundrum about bare shaft testing. Here's the details

Bow: Recurve 60"
59# @ 28.5"
I draw 28"
Cut 3/16 past center with a velcro rest and plate
16 strand B50 String
Nock point 1/2 inch above the shelf.

Arrows: Switched to carbon last year, so that's all I've been shooting.
CX Heritage 250
Cut to 29.75 to back of insert
50 gr brass insert
Field points: Various sizes

Form: good, not excellent.. Split finger, tendency torque string sometimes, basically I can repeat my form consistently and get the same arrow speed through a chrono, and get decent accuracy as well.

Now here's what causes me to curse a little. I started last summer fooling with bare shaft testing, and I never have really been able to get conclusive results, but I do get consistent results.

According to the calculator, with a 175 grain field point, my arrow should be over ten pounds weak in spine.

I'm bare shafting at 20-25 yards. Done this with field points of 125 grains, 175, 200, and 250. I can shoot my fletched arrows into a nice group where I'm aiming no matter the point size. If I shoot all these sizes in a session with good form, I get a nice group of arrows. Period. The 125's will be a bit high sometimes, and the 250's will be a bit low sometimes. If I miss right/left, It's usually left. I attribute this to form issues. I miss to the right a reasonable amount of time with the 250 gr. points.

Now when I start shooting bare shafts, I get the following:

125 gr, Always far to the left. a foot or so
175 gr. Always less to the left. 4-8"
200Gr Always right with the 175 gr.
250 gr. tend to shoot right with my fletched shafts, except that it shoots with the lighter points better. If I shoot it with 250 gr fletched only, it also tends to be left.

According to the calculator, 250 gr points give me 46.4 spine, where 74.5 is needed for my bow. With the personal form factor at 0. However, my bare shaft testing shows that my arrows are too stiff no matter the point size. Either that or I'm doing something wrong - like a form issue that is magnified by no fletching.

Any ideas?

[McDave]

I wonder if your arrows are too close to center shot with your shelf cut 3/16" past center and a velcro plate.  Most people shooting fingers would prefer their arrows a little left of center (for a RH shooter).  I'm not familiar with CX Heritage 250's, but the carbons I shoot are fairly small in diameter, and I would have to build out the side plate a little if it were my bow.

Sorry I couldn't give you specific advice on your problem, but maybe someone else can.

[mrjsl]

It is cut 3/16 past center. I just double checked it with a precision rule. I'll try to build it out a tad more and see what happens. That is one thing I haven't fooled with a lot. I've either used velcro or a bear calf hair plate, which I believe is thinner.

The Bow came with a somewhat thicker rug plate I guess, I can't really remember. It's a Bruin Huntmaster.

[Dan Adair]

What McDave said.

I'm a firm believer in bareshaft tunes, in my time with tradbows its always provided me the best tune in the end.

I also believe that you need the arrow sitting outside of center to some degree.  If you don't bend it some in the first half of paradox, the tail end never really clears the riser.  You end up with what a buddy of mine calls a "slap tune" where the tail end comes back into the riser too soon.  You can usually spot this condition in excessive feather abuse, or skid marks on your cap dip or wraps, and a spine that common sense tells you is way too soft, but arrow flight looks good, but will toss out a huge flyer once in a while.  If you know what to listen for you'll hear a "clacker".

[mrjsl]

I don't believe 3/16" past center is too uncommon in recurve bows. My arrow is 5/16" in diameter. so with the velcro plate, it was already outside center shot somewhat.

I did build it out some. I put a piece of Moleskin and then velcro on top of that. So the plate is a moleskin thicker than before.

I shot a round through it, and my 175 bare shaft shot with my 175 fletched, the 125 bare shaft still printed stiff, and the 250 printed a tad weak. basically it moved all bare shaft impacts to the right, but I only shot one round. Will try it some more and report back.

[NBK]

For what it's worth, Stu's Calculator, although very cool at seeing KE and stuff, doesn't really jive for my tuning.  I initially used it and my arrows were waaaaay stiff, (and tuned to perfection using Dan's "slap tune"!)  My best tune uses arrows that are about 20lbs weaker than recommended.

[mrjsl]

I don't believe my arrow is hitting the riser. No feather wear I'll check it closer, though.

[Al Dean]

2 questions.  Are you holding your bow vertical?  And with the arrows left of center are they straight or leaning nock right or nock up ect.?

[LongStick64]

I use the bareshaft for two purposes. One of course to tune my bow setup. But I really use it to tune my form. I get an arrow that based on every stat should bare shaft tune well for me and then I start shooting. Without question it shoots as good as my form goes.

[shortstroke 91]

I agree with NBK, I put my stats in and the results were #25 stiffer than what shoots perfectly in my bow. I can put bareshafts and fletched touching each other @ 20 yds with the current setup. With what Stu's chart said I was so stiff there was no way to get good flight.

[Dan Adair]

Originally posted by Al Dean:
2 questions.  Are you holding your bow vertical?  And with the arrows left of center are they straight or leaning nock right or nock up ect.?

Good point...  Some poeple do forget that it all is relative to how much you can't your bow.

Example: if your limbs are at 2 and 8 O'clock and your arrow is noon knock high 3", then you have a weak shaft and the nock set needs to come down a little...  You don't just have a a nock high.


Also worth mentioning, when I bareshaft at 20 yards, I'm always a little nock high.  If I get a perfect bareshaft, I'll get some up/down porpoise once there's feathers on the back end.  I never did figure out if its from my 4 fletch hitting the riser, or the extra 12 grains of tail weight did it  

[zetabow]

To get correct Bareshaft results you first have to have a very solid form foundation.

Also I always keep a couple of Bareshafts handy and use them once a week, if you have a sloppy release it shows big time with Bareshafts, it helps keep my release sharp.

[NBK]

Zeta,
You ever use Stu's calculator?  If you have, I'd like to hear your results.  Thanks.

[mrjsl]

I did two things that improved matters a little. I raised the brace height slightly and built out the plate one moleskin thickness. Took it out Saturday morning and shot 175 gr point bareshafts in the same group with 175 gr fletched, but only shot one round. Went to a 3D shoot and shot 180 on 25 targets. All my misses were to the left. May be low, but is not bad for me.

I'm leaning towards the idea that it is a release issue. Once in a while I get bad flight out of a fletched shaft, and this results in a miss to the left. I am going to work on my release some.

[zetabow]

Originally posted by NBK:
Zeta,
You ever use Stu's calculator?  If you have, I'd like to hear your results.  Thanks.

No I never used Stu's calculator, I'm using 610 Easton Navigators for Field and carbon Express 150's for 3D, I just used their spine charts.

I start off 10 yards to get basic tune then fine tune at 20  and then again 30 yards and final check at 40 yards, I'm shooting a full ILF target rig (without sights) so I have a good choice of tuning options to get perfect arrow flight.

         

Dont forget even things like choice of Tab/Glove can influence bareshaft tuning. If you change ANYTHING you should re-check tuning.

     
This was a gift from a German Bowyer, just made some poc's for it and plan to shoot Fita world 3D's with it in Sept, I'm liking the accuracy of the Recurve but Longbow is still in my heart, very pleased with this bow, good speed and nice build quality....I never bareshaft woodies so Bareshaft tuning is fairly new to me (9 months)but found it VERY effective way to tune carbon arrows to the bow.

[CEO]

For what its worth, my tuned arrows come out about 20 lbs weaker than recomended by Stu's Calculator.

[mrjsl]

Well, here's the final verdict on this issue.

I've slung hundreds of arrows downrange under all kinds of conditions, and I discovered a lot.

The biggest revelation to me was that the spine calculator is not only off in my case, but it helped confound my efforts to get good arrow flight. I kept trying remedies that brought the bow and arrow closer together on the calculator, when what really worked was to forget about that and correct for too stiff arrows only.

In a nutshell, I have to shoot 250 gr points at the given arrow length for best flight. I can shoot 175 just fine, but if I do anything wrong in my release, or it rains and my feathers mat down,  or I lock my bow arm straight, I get bad arrow flight and it cost me a hit. I shot two 3D tournaments where I should have shot 200+ out of 250 and dropped +-20 points because of a less than perfect release or wet weather causing noticeably bad flight on 5 or 6 targets.

I like the extra speed of the lighter points on longer range targets, and I'm going to experiment with my next batch of shafts by starting longer. Until then I'll have to shoot 250 gr, because I cannot make them fly bad if I try.

For what it's worth the spine calculator is right about my arrow speed and weight, and I do find it useful for comparing two different arrows. It has to be inaccurate re. my bow, but I don't know how - I measured everything precisely.

[PaddyMac]

I bare shaft tuned myself into arrows way too stiff and too long with points too heavy. Then I saw a conversation with Big Jim Babcock and added a velcro rug to my calfhair stock plate and bare shafted my way back to 5575s and 175 pts.

I noticed I was missing consistently to the right and on a whim saw the suede back of a bateman tab laying around and taped it over the velcro. It moved my groups to the left right onto the target.

I'm not familiar with your shafts, but with a hunk of suede and some masking tape you can find out a lot. There is now a polished edge along the suede that wasn't on the calf hair.

So at 3/16ths centercut my finished plate will be two layers of buckskin under a heavy duty velcro rug with 5/16th arrows and 175 gr. points.

[mrjsl]

I had to go down to just a calf hair plate only - very thin. Building out the plate made my too stiff arrow act stiffer, but it did make my bow and arrow closer in the calculator.

[Dan Adair]

I used to know a guy at the race track that was known as the Stock Car Whisperer.  One day we had a lengthy discussion about how bigger horsepower cars like more cross, and splits on spring rates, and shock tuning....  He looked me straight in the eyes and said, "Scooter, you gotta give the car what the CAR wants"  So we started doing just that, and with a set-up that shouldn't work, set our first track record...

Thats got a lot to do with bows too...  you straight up outsmarted yourself.  Let that be a lesson Scooter   :D