Broadhead Retuning

[BigWoods]

Having a bit of a head scratcher here.

I had my VPA 3 blade unvented broadheads grouping with field points out of my Mathews Traverse out to 60yds. Last week I did a bit of turkey hunting and and a moderate amount of practice with the bow. As I was readying for the CBC I found that my broadheads were now impacting around 5" left at 50yds. Today I tried walking the rest to the right (which is what I originally had to do) and it simply moved both fp's and broadheads over proportionately rather than tightening them up. Returning my rest to where I started brought the field points right back to center.

What sort of things should I be looking at to explain this shift? Any form issues that I should look at?

Thanks!

 

[Billy Goat]

Possibly lost some poundage on your bow and you are now seeing a stiff spine reaction. I'm not familiar with the Mathews to know what cam system it has to know if it would be cable or string stretch to decrease poundage.

Could also be something in your form changed a little bit. Some bows a slight change in hand torque would easily shift your impact 5" at 60 yards with bh's.

 

[Brendan]

Broadheads left of field points, move the rest left.

But - something changed. Either strings settling / stretching, rest moving, etc, or it's you. From a form perspective - anchoring too deep in your face (facial pressure) or hand torque can do it. I've had different reactions from wearing a glove or not because of friction on the riser (which is why I like a rubber innertube wrapping the grip)

 

[BigWoods]

I must be up around 1000 shots from the bow so I imagine string stretch might be an issue. Maybe I'll give it a 1/4 or 1/2 turn and see if that bring things together.

I'll definitely keep paying attention to form...doesn't feel like anything has changed and I think I've been paying attention to hand position, but shifts always seem to happen subtly over time, so they're hard to catch.

The whole move left vs move right broadhead tuning confuses me. Seem like half say one and half the other. I'll try sliding things left for a try.

 

[RosinBag]

If you were consistent when you were moving the rest right, I doubt it is form if you continue to group.

And I think you should move the rest away from the impact of the broad head, so if your BH’s shoot left I would move the rest right. But it can’t hurt to try both.

I would mark your cams after you confirm they are at the timing you want. Then it will 90% of the time be a center shot issue or yoke issue, but your Mathews has no yokes. So moving the rest will probably get things squared away.

The other thought is maybe you are shooting better now, and you are shooting well enough to realize maybe they weren’t impacting the same.

 

[madkaw284]

As said before, if your fixed blades are impacting left of field points, you need to bump rest to the left or add half twist at a time to your right yoke(s) or shimming cams to the right. But as also mentioned, sometimes you need to check yourself.


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[Topo_trekker]

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[RosinBag]

 

[Brendan]

Have to respectfully disagree with Doug. We (Rokslide in general) get into this argument all the time here, but:

Gillingham / Gold Tip: Left Broadhead = Rest Left

John Dudley - Paper Tuning

Right Tear - Rest Left (1:35)
He says when that doesn't work - improper release, improper facial pressure, improper grip, etc.

The image Topo_trekker posted above is the Easton Tuning guide.

With that all said, never hurts to try, and when things get real far out of whack, you get fletching contact, lots of torque - all bets are off....

 

[5MilesBack]

That's interesting, because most would say that adjustments for right or left hand shooters are the same for release shooting. But he says to "increase the load on the cable guard" to fix a right tear. For right and left hand shooters, that does exact opposite corrections because that pulls the cables and the cams to the right for a right hand shooter and left for a left hand shooter.

So........if that's the case, are yoke and rest adjustments opposite as well? Most would say no. Or perhaps Tim just failed to mention that a lefty might have to decrease the load on the cable guard?

But then here's another question: Increasing the tension on the cable guard for a righty is going to pull the top cam lean to the right.........which is the opposite direction that he uses for his yoke adjustments to correct that right tear. Those seem to be opposing corrections.

 

[BigWoods]

Thank you all for the feedback! Definitely gives me a path to try sorting this out.

I shot a bow a bunch back as a late teen, but never past 40yds. With the new bow I've been successfully stretching things out to a good bit further which highlight the minutiae and providing a good learning process.

I've got to the point where I have enough consistency to call the down range results.

This was my first grouping at 80 last week (2 arrows are coming in at a different angle due to the bag shifting). Obviously the sight tape needs some work.



I'll probably start up the CBC with some mechanicals and dive in to this more afterwards.

 

[Brendan]

@5MilesBack - You really need to watch the videos... The cable guard direction will be the same, but more/less string pressure will be opposite for righty and lefty shooters. Tim mentions this in one of the videos if you watch them, acknowledging differences for a lefty, and what I posted is a screenshot from when he talks about it.

Think of it this way. You want the powerstroke of your bow and the rest to be in alignment. If the powerstroke of the bow is to the left of the rest you have two options. First, move the powerstroke to the right, second move the rest to the left. To move the powerstroke to the right: Tighten Right Yoke/Loosen Left, Shim Cams to The Right, More Pressure on the Cable Guard for a righty/less for a lefty, or you can play with limb deflections if they're aysmmetrical. Basically - the rest moves in the opposite direction as you would the cams/powerstroke when trying to correct the tear, it wouldn't make sense to move them both the same way.

Side Note, videos are here:

GoldTip

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[5MilesBack]

To move the powerstroke to the right: Tighten Right Yoke/Loosen Left, Shim Cams to The Right, More Pressure on the Cable Guard for a righty/less for a lefty, or you can play with limb deflections if they're aysmmetrical.

Watched the video again........and he did say that for lefties the adjustments would be opposite. So that explains why moving the rest towards the FP's works. But your quote above is what I was talking about. If you tighten the right yoke/loosen the left it leans the top of the cam to the right. But more pressure on the cable guard for a righty does the opposite, it leans the top of the cam to the left. How can opposing adjustments accomplish the same thing?

 

[Brendan]

Watched the video again........and he did say that for lefties the adjustments would be opposite. So that explains why moving the rest towards the FP's works. But your quote above is what I was talking about. If you tighten the right yoke/loosen the left it leans the top of the cam to the right. But more pressure on the cable guard for a righty does the opposite, it leans the top of the cam to the left. How can opposing adjustments accomplish the same thing?

Tightening cable guard for a righty does not do the opposite - it pulls the cam (more) to the right. Tighten cable guard, More tension on cables, cables pulled more to the right, more clearance for Vanes, but that tips the cams to the right.

Guessing you're getting it reversed because you're a southpaw...

 

[fiskeri1]

I'm sorry for the OP but this sounds just like my experience with the Triax. Be prepared to keep moving things around (left or right and/or tophat swap) every few weeks.

Just curious, are you shooting the Mathews strings or did you change them out?

 

[BigWoods]

I'm sorry for the OP but this sounds just like my experience with the Triax. Be prepared to keep moving things around (left or right and/or tophat swap) every few weeks.

Just curious, are you shooting the Mathews strings or did you change them out?

Yes, I'm shooting the stock strings at this point.

As said, once I'm done with the cold bow challenge, I'll work with my grip a bit and then try adding a bit of weight back. I'm shooting 300 spine arrows cut to 29" which I believe might be getting just a bit on the stiff side if I'm a bit under 60lbs (200 grains up front). I'll probably also slide the rest left to see if that helps.

If all that fails then I might look into top hats and like (possibly new strings?) ... unfortunately the archery shop is 1.5hr round trip and they don't have a 50+ yd range set up.

 

[TravisIN]

Can you give so more information on your arrow setup, as well as your rest? Have you checked all your specs to see if they stayed the same? How does your center serve look?


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[BigWoods]

Can you give so more information on your arrow setup, as well as your rest? Have you checked all your specs to see if they stayed the same? How does your center serve look?


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Arrows are Beeman ICS Classic 300 Spine. They're actually cut to 29 5/8". 100gr brass insert, 100 gr heads. Steered by 3 Blazer vanes slightly offset.

Using the Mathews/QAD integrate rest.

What specs should I check? (Excuse the ignorant question!)

Center serving seems to be holding up well.

 

[TravisIN]

Draw weight, cam sync, brace height etc. How is your nock fit? Too tight, too loose, any pinch?


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[IdahoHntr]

Have to respectfully disagree with Doug. We (Rokslide in general) get into this argument all the time here, but:

Gillingham / Gold Tip: Left Broadhead = Rest Left

John Dudley - Paper Tuning

Right Tear - Rest Left (1:35)
He says when that doesn't work - improper release, improper facial pressure, improper grip, etc.

The image Topo_trekker posted above is the Easton Tuning guide.

With that all said, never hurts to try, and when things get real far out of whack, you get fletching contact, lots of torque - all bets are off....

Dudley disagrees with you on the broadhead tuning aspect.

The concept behind broadhead tuning is that by moving your rest very slight amounts it will affect your fixed blade broadheads more than your fieldpoints because of the increased surface area on the fixed blade heads. So if fixed blades are hitting left of fieldpoints then by moving your rest left the distance between the two will increase. The fieldpoints won't ever catch up to the broadheads because the fieldpoints are affected less than the broadheads by each rest movement. If you move the rest right eventually the fieldpoints and broadheads will hit in the same spot, but slightly to the right of the orignal aiming point.