# Weak spine hitting left?



## Sled (Jul 19, 2014)

I've been troubleshooting what I believe to be a weak spine issue. After working out a nock high bare shaft I still get a significant nock right and consistent left impact. 

Specs:
Prime black 3 @69lbs 31"+ DL
shooting a 445gr Easton hexx 330 spine @28.5" carbon to carbon.
175gr point weight.
Right hand shooter

I realize I'm on the weak end of the spectrum but that's what I had on hand. I do have some 260's on order but am confused on what I'm seeing.

The pic is prior to working out the nock high, which is likely also due to the spine issue.










It's my understanding that a weak spine typically presents poi right of fletched and tail left for a RH shooter. To rule some things out I started to strip a few other arrows I had available. Both were 300 spine, one had a pont weight of 150 and the other at 110. The heavier foc arrow had a similar issue to the hexx, nock right poi left. The light weight 300, which is stiffer, stacked right in with fletched. They were parallel and what I'm looking for except for the low overall weight and low foc.

So, I think I have the answer but am confused on the presentation of the problem. To be honest, I typically french tune and call it good. It has worked for the mechanicals I've shot Ive the past but this year I plan to go fixed. Anyone here have the same issue or was my bow made in the southern hemisphere?


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## Sled (Jul 19, 2014)

i should also mention that i did turn the limbs down a couple turns to see if i could get it to tune w/ 330's but i did not see any significant improvement. at least not enough to get it to tune. 260's will be here hopefully friday.


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## nuts&bolts (Mar 25, 2005)

Sled said:


> i should also mention that i did turn the limbs down a couple turns to see if i could get it to tune w/ 330's but i did not see any significant improvement. at least not enough to get it to tune. 260's will be here hopefully friday.


Not a spine issue.
This is a form issue.
If right handed, double the length of your d-loop, anchor farther back on your head. Longer d-loop will position the nock farther back on your head.

Swing right elbow more clockwise behind your head.


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## Sled (Jul 19, 2014)

Alan, I'm away from my bow until the weekend but I'm willing to try that. I currently run a longer loop than most but can lengthen. Doubling would put me around 1 5/8". I'm a 30"DL by the book but feel more comfortable anchoring back under the mastoid process or behind the ear (wrist strap index release). That puts me maxed out on the prime cams. I might be able to get a little more twisting cables or changing my let off.


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## Robspartacus (Feb 20, 2017)

The black series and nexus often have right tears according to many. Mine does not, but if your DL and D Loop are correct, you may need to shim your cams. Your factory shims will be 2 dot shims in all four corners. You might need 1 dot and 3 dot cam shims. As close as you are now, you might not need much added D Loop length to correct your issue. Go ahead and do what Nuts&bolts says to see. I bet it flips your right tear to left. 

Here are some pics of my Nexus 6 bareshafts at 20 yards. If it isn't a grip issue, the D Loop length can and will cause bareshafts to drift. These random pics show what grip pressure can do. I did this intentionally for some Prime guys to show just how grip pressure can and will alter bareshaft flight. I intentionally made bad shots with my grip to explain just how being too low (low wrist push) and too much lifeline contact will give bad results. I currently have both my Prime Nexus 6 and Mathews TRX36 shooting good bareshafts at 20 yards. You aint far off.












































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## Sled (Jul 19, 2014)

thanks rob, i'll give that a go. prior to raising the rest i was slapping the same POI with bare shaft and fletched but had the high right nock. at one point i damaged the bare shaft with the tip of the fletched and had a near miss when i didn't flex it. my picture above was about 3 small movements away from getting the nock high gone. 

any ideas why the 300 spine with a low tip weight would stack in parallel with the fletched 300? 

either way i'll work on it this weekend and try to remember to take some pics.

Alan,
when setting up this bow i went back and shot groups from 28"dl to 31". the longer dl 31" grouped better for me and felt more like my triax set a 30". that bow was turned down and i also anchored below the mastoid process. do you think moving the anchor lower and behind the mastoid process would give me better flight?


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## Robspartacus (Feb 20, 2017)

I run Victory VTAC 25s (300 spine) with only 100 grains up front with absolutely no issues. My Mathews 60lb TRX36 shoots them great (20 yard bareshafts) . My Prime Nexus 6 60lb shoots them great(29 yard bareshafts). My Bowtech Reckoning 35 60lb shot them perfectly out to 40 yards bareshaft. I am a firm believer that you can't be too stiff and also believe FOC is the most overrated crap there is as far as accuracy goes (3D/Target shooting). As far as target archery goes, I also don't believe bareshaft results are the end all be all as far as accuracy goes although in some bows it actually is. The Hoyt Prevail 37 SVX and Invicta 37 SVX actually shot better for me with high left and high right tears. The Reckoning and Rezult shot best with perfect long range bareshaft results. I have not done long range line tuning yet on my newest bows but I'm willing to bet the Mathews TRX36 will be best tuned with bareshafts and the Prime may be as well. 

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## Sled (Jul 19, 2014)

good to know. i may still try both lengthening the d-loop and increasing the spine to the 260. my best shooting bow was a mission bow set at <65lbs shooting GT hunter 340's with 110gr up front. they were single digit foc and did kill animals but pass throughs were in short supply. when the shop blew up that bow it was never the same. that led me to new bow with more foc and overall arrow weight...which seems to have dropped my accuracy over the past few years.


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## E_L33T Arch3r (Oct 6, 2012)

Robspartacus said:


> The black series and nexus often have right tears according to many. Mine does not, but if your DL and D Loop are correct, you may need to shim your cams. Your factory shims will be 2 dot shims in all four corners. You might need 1 dot and 3 dot cam shims. As close as you are now, you might not need much added D Loop length to correct your issue. Go ahead and do what Nuts&bolts says to see. I bet it flips your right tear to left.
> 
> Here are some pics of my Nexus 6 bareshafts at 20 yards. If it isn't a grip issue, the D Loop length can and will cause bareshafts to drift. These random pics show what grip pressure can do. I did this intentionally for some Prime guys to show just how grip pressure can and will alter bareshaft flight. I intentionally made bad shots with my grip to explain just how being too low (low wrist push) and too much lifeline contact will give bad results. I currently have both my Prime Nexus 6 and Mathews TRX36 shooting good bareshafts at 20 yards. You aint far off.
> 
> ...


Can you explain the grip you’ve found works the best?


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## Robspartacus (Feb 20, 2017)

E_L33T Arch3r said:


> Can you explain the grip you’ve found works the best?


45 degree. Basically, do not let the grip cross the life line.

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## E_L33T Arch3r (Oct 6, 2012)

Robspartacus said:


> 45 degree. Basically, do not let the grip cross the life line.
> 
> Sent from my SM-N960U1 using Tapatalk


Is there another thread that explains what variations in grip caused those bare shafts?


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## Robspartacus (Feb 20, 2017)

E_L33T Arch3r said:


> Is there another thread that explains what variations in grip caused those bare shafts?


Honestly, instead of reading a post about it, actually experiment yourself. It will make more sense to you. When you don't have a proper grip, you ultimately torque your bow. 

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## Sled (Jul 19, 2014)

after a bit of experimentation I'm not sure I'm much further along than I was last weekend. I did lengthen the d-loop and changed my anchor point. To accomplish this I went back through resetting the peep, twisting the string and changing the timing. After twisting the string I did need to go back and reset my center shot through the Berger hole. I checked for the rest parallel to the riser and did have to bump that out a bit. After all that, I feel a bit overextended with such a long d-loop. the draw length itself is at 31.5 in not including the extra inch and a quarter of d loop. I will continue to work on this but right now it looks like mechanicals this season for me.


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## Sled (Jul 19, 2014)




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## Sled (Jul 19, 2014)

Here's an update:
I went back and forth on what to do this year but things have started coming together with a 330 spine arrows I started with. I had to back the pounds down on the bow due to a shoulder sublux at work. That dropped me 5 lb into the 67 lb area. I focused on form and put the draw length and let off to a comfortable 31.25". The bear shaft straightened up and started grouping. I also pulled out the new iron will single bevels that I wanted to shoot this year and lo and behold they group out to 60 just fine. I may still throw a mechanical in the quiver but I think I may be shooting the iron wills with a lighted nock for arrow recovery. I'd have a hard time stomaching losing a broadhead that cost more than $30, but it seems like the time to do it if I was ever going to.

Thanks again for the replies and help.


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