Help understanding a nock high bare shaft...

[The Ursus]

Ok, I could use some help understanding why I’m getting nock high out of my recurve.  I’m shooting a 60” recurve, center shot, 55 lbs @ 28.5”, brace height 7.25”, nock point 3/8” above center.   I shoot split finger, one over and two under.  

I’ve found an aluminum shaft that will bare-shaft quite well but with an elevated brush rest.  It’s a 2219 with a 145gr head.  I forget how long it is but I know it’s somewhere around 29-30 inches (I’m at the office so I can’t go measure it right now).   It appears to have no left or right kick when shot at 13-14 yards.  

I’m glad that it shoots well with the rest but I’d like to do without it and keep shooting off the shelf like I usually do.  So last night I took the rest off, moved my nock point down to compensate and put a few shots through it.   The first few shots were nock high, so I lowered the nock point.  Same thing.  Lowered it again, same thing.  I brought it down to center, same thing but more.

So my question is, why would an arrow shoot well off of a rest but not off of a shelf?  The shaft must be coming off the shelf differently.  Could someone help me understand why?

 (I’ve seen this happen with other bows shot off the shelf, so I know it’s not the bow’s fault)

[madness522]

Could be the nock is too low and there is a bounce effect showing it as a nock high.  Try raising the nock to 1/2 or 5/8 and see if it gets better or worse.

[BobCo 1965]

Ursus, I had almost the exact same scenerio that you have mentioned on a certain recurve. I believe that no matter what I did, I was getting some sort of contact on the shelf, kind of like what madness referred to.

What I ended up doing was taking a piece of shaft from a q-tip and placing it under the rug rest directly above the deepest part of my grip.

It took care of the problem.

[The Ursus]

Is there anything other than nock point placement that can have an effect on this?  I've moved the nock point all over the place and nothing seems to help.

[The Ursus]

Thanks Bob, I forgot about that option.  It's now on my list of things to try.

[dan ferguson]

Don,t forget to try different feather placment, cock feather up etc, sometimes if you get the feathers just right you can lower nock point,at least it works sometimes

[Jack Denbow]

The problem is the arrow is kicking off the shelf. If the shelf is wider than the arrow this seems to be a common problem. If you build up the shelf about 1/8" and make it no wider than the arrow the problem will go away. You can use a piece of leather or whatever. Your brush rest is no wider than your arrow and is above the shelf which is why the arrow shoots good from it. A lot of bowyers are starting to cut the edge of the shelf off so it is no wider than the arrow. I hope this helps.

[katman]

Jacks explanation sounds very good, I had a knock high problem with a certain shaft and turned out to be to high spine, although no fishtail was there. More point weight helped.

[Steve P]

2219 does seem stiff for 55#.

[The Ursus]

Thanks guys, last night a put a lump under the strike plate and did some shooting.  I think it helped a little but still has a ways to go before it's gonna be hitting the target straight.  When I get home I'll check and see how wide my "lump" is compaired to the width of my arrow.  Seesh, talk about sensitive.  

Yeah, I think the 2219 is stiff but I've been messing around with different weight heads (all the way up to 250) and the 145 seems to have the least kick.  I've got a bunch of shafts (aluminum, carbon, wood)laying around the garage that I've bee trying and all have been giving me some variation of knock high.

[last arrow]

Your comment about all your shafts giving you the nock high problem makes me think it could be a form problem.    

I have had the same problem and found that by lowereing my drawing elbow so that my forearm is in line with the arrow and making sure I held the string parallel to the limb (cant your string hand the same as your bow) helped correct the problem.

Try putting some "string line" chalk (it doesn't take much)on the last 4- 5 inches of the knock end of your arrow and shoot some and see if it leaves a mark on your shelf to confirm were the arrow is hitting the shelf (this does not rule out a form problem). That may help clarify the sevarity of the problem.

[The Ursus]

I'll try the string line chalk.  I wonder if I'd get the job done the same by rubbing chalk-board chalk on the back of the shaft.  Hmmm....  Good stuff. Thanks for the suggestion on my elbow form, I'll consider that too.

[last arrow]

I forgot to mention, you may want to look in the mirror at full draw or video your draw, it will make it easyer to know what your elbow is doing.  The bad thing about videos is you end up with a whole list of things to work on.