Mathews Heli-m and QAD ultra rest?

[NickB]

So I bought a Heli-m and I have a QAD ultra rest on it. The bow is #70 and 29.5 inch draw. My rest is all the way over to the left as far as it goes. I'm getting a pretty good paper tune hole now, as of a week ago I couldn't get a good tear and we narrowed it down to my arrow being under spined, I moved from a 340 to a 400. but I was curious if anyone else had that issue when tuning a Heli-m with a QAD.

[indynotch50]

If you're shooting a 70# bow, you should be at a .340. A .400 is way under spined. If your rest is all the way to the left your center shot has to be way off. Don't let the paper tune fool you. It's possible to manipulate the paper to be correct but your rest we well off.
Get the .340 back out and play with it. You should be able to get your center shot and go from there.
Any more questions just ask.

[NickB]

So is a 400 stiffer than a 340?

[Jim]

Nope...other way around.
The higher the number the weaker the spine.

[trial153]

Make your corrections in steps otherwise you won't get a handle on the real issue.

First correct the spine issue and move up to a .340

Then re adjust your center shot back to about dead center... Then preceded to tune...
If that didn't get you a MUCH improved tear I would then...
Look to a draw length adjustment as a common denominator to horizontal tear is incorrect draw length....

[NickB]

I took my bow into my local pro shop, I had a 340 arrow and told them I was getting bad arrow flight and wanted to go to a 300(only because I had some people suggest that for 70# 29.5 draw with a 29 inch arrow) So I go in there say something about a 300 and pro shop guy tells me that 300 is way to stiff and I will lose a lot of yardage and my arrow will arching a lot more, so he talked me into a 400 which I asked multiple times if it was a stiffer spine and he said it was. I got them home and paper tuned my bow and was getting a perfect bullet hole but my rest was all the way to the left. My draw length is perfect. Not sure why he would suggest 400 spine. Any tricks or tips on getting center shot?

[robchevy2]

A 400 is a weaker spine than a 340. Do a walk back tune and you will see which way to move your rest. just google how to and it will explain everything. I only draw 58#and I use a 400 spine arrow

[Bootlegger]

The guy at the shop was wrong....the 400 is weaker.

[Jim]

340's are even weak for your setup.

[NickB]

Sorry I can't read what it says on that picture. Does it suggest 300?

[indynotch50]

The spine measures deflection over a length. So less deflection means the spine is stiffer.
***With a 100 grain tip***
The .400 really runs out about the 65# mark. The .340 spine runs out around the 70# mark. I shot CE .340s perfectly through my z7x.
If you move to a 125 grain tip, you'll have to move to a stiffer shaft as the added weight in the front will cause your arrow to want to bend more out of the bow if you will.

The guy at the "pro" shop was completely wrong and sold you the arrows. Which actually, is quite dangerous.

Go with the .340 and a 100 grain tip, or a .300 and a 125 grain tip. Both will give you perfect bullets when your arrow is at center shot.

[NickB]

So I took the arrows back and the employees there were dumb founded that this guy sold me .400 arrows. I ended up exchanging them for FMJ .300. So hopefully now I can get this Figured out.

[bowhuntjoe]

Get 340 spine arrows, get the centre shot back to normal, check the arrow is knocked to a perfect right angle to the string using a bow square, start paper tuning. If it is not tuning with the centre shot almost spot on you may want to check for lean on the idler wheel.

I had a Diamond Marquis ages ago and had a simular problem, it would not tune with the rest centred no matter how perfectly squared off everything was, I checked cam lean and it was WAYYYYY off, fixed the lean on the idler wheel and it tuned really nice after that with the arrow rest in the correct position.

I hope this helps, mate.

[maxpetros]

Get 340 spine arrows, get the centre shot back to normal, check the arrow is knocked to a perfect right angle to the string using a bow square, start paper tuning. If it is not tuning with the centre shot almost spot on you may want to check for lean on the idler wheel.

I had a Diamond Marquis ages ago and had a simular problem, it would not tune with the rest centred no matter how perfectly squared off everything was, I checked cam lean and it was WAYYYYY off, fixed the lean on the idler wheel and it tuned really nice after that with the arrow rest in the correct position.

I hope this helps, mate.

How do you correct cam lean?