Broadheads consistently hitting left of FP, regardless of moving rest

[Ucsdryder]

Turning down the limb bolts is just a test. It doesn’t hurt to turn them down and if you turn them down and you add 100 grains and you get the correct arrow flight, then you’ll know. You can either leave them turned down or get new arrows. At this point you need to keep trying stuff until you figure it out.

 

[Brendan]

I'm not familiar with Pinwheel, but thanks for looking into it. The numbers aren't accurate (my arrow weighs 482gr and it's right around 290fps). I'll get you the correct information when I get home. I've got a notebook that I keep all the raw numbers in.

I'll re-run it for you when you get the numbers. Looked it up: Spine will be even weaker / worse with the insert weights.

 

[Billy Goat]

I was planning on just swapping a 100 gr broadhead rather than turn down the limb bolts. Do you think that will be suffcient?

I think generally 25 grains of tip weight is roughly equal to 3#'s. In other words putting 100 grain tips on instead of the 125's would be like loosing 3# of draw weight in terms of the dynamic spine.

I guess you could try the lighter tips, but it won't necessarily confirm your not underspined if it doesn't fix it. I think you might need to loose over 5#. I prefer to do it with the limb bolts, also you will be increasing arrow speed with the lighter tips that can make things more difficult as well.

 

[bjfoxhoven]

I agree sounds weak too. Also may not be the issue here, but just a thought since all your arrows are set up the same. Double check the squareness of the nock end of the arrow. I noticed some inconsistencies lately and noticed the nocks not sitting flush with some arrows. If you indexed you’re nocks though you would effectively move the BH impact point around as you go.

 

[TheCougar]

1. Grip and posture - Standby
2. Spine: BEA Spartan 300 spine/.001; carbon to carbon shaft length is 27.5” (247.5gr); 30gr brass insert weight + steel insert 27gr + 125gr broadhead; nock bushing 10 gr; nock 9 gr; 3 x AAE Max Stealth 27.6gr (9.2gr each). Total weight should be 482gr, 14.4% FOC, 289 FPS. Centergy Hybrid 78#, 29” draw.
3. Flexis: 560 degrees off of fully tightened. A little Over 1.5 turns from the bottom.
4. Paper tune: standby.
5. Bareshafts: see below


40 Yards: FP on the right, 125gr BH on the left. This is pretty normal right now.

15 yards BARESHAFT

20 yards bareshaft:

20 yards bareshaft and 100gr point on bareshaft. (Down from 125).

20 yards bareshaft with 100gr point on bareshaft AND -2 turns on each limb bolt.

40 yards: -2 turns on each limb bolt, 125gr BH on the left and FP on the right.

 

[TheCougar]

Didn’t get to the rest of it tonight. I was busy cleaning this thing...

 

[TheCougar]

 

[Brendan]

2. Spine: BEA Spartan 300 spine/.001; carbon to carbon shaft length is 27.5” (247.5gr); 30gr brass insert weight + steel insert 27gr + 125gr broadhead; nock bushing 10 gr; nock 9 gr; 3 x AAE Max Stealth 27.6gr (9.2gr each). Total weight should be 482gr, 14.4% FOC, 289 FPS. Centergy Hybrid 78#, 29” draw.

Specs say 476.1 gr (add up your figures above), if yours weigh 482 thats probably glue or minor component differences.

Here's if I fudge the weight up using shaft GPI to evenly distribute it, then adjusting IBO down from 338 to get your actual arrow speed. Still marginally weak.

 

[Brendan]

Here's what the specs say with no adjustment

 

[TheCougar]

Specs say 476.1 gr (add up your figures above), if yours weigh 482 thats probably glue or minor component differences.

Here's if I fudge the weight up using shaft GPI to evenly distribute it, then adjusting IBO down from 338 to get your actual arrow speed. Still marginally weak.

View attachment 176363

Is that enough to matter? I’ll should have more time tomorrow to mess with the bow and experiment

 

[Jimbob]

I have built arrows using the software and always stay on the stiff side. I think that reading shows it’s too weak and I certainly would be adjusting poundage or buying new arrows.


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[Brendan]

Is that enough to matter? I’ll should have more time tomorrow to mess with the bow and experiment

Maybe. Some bows you can tune a weak shaft easier than others, and these programs are only a starting point. I would 100% test by turning down the draw weight and then also rule out fletching contact. Those are both easy and can save you a ton of headaches.

 

[rj2]

I shoot a PSE with HD cams, but was having same issues. I ended up swapping shims on top cam to move it slightly right and it definitely helped. I still need to do some fine tuning but if your bow uses shims maybe look into moving the cam or cams over

 

[TheCougar]

Maybe. Some bows you can tune a weak shaft easier than others, and these programs are only a starting point. I would 100% test by turning down the draw weight and then also rule out fletching contact. Those are both easy and can save you a ton of headaches.

Posted some pictures from shooting tonight.


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[Billy Goat]

Posted some pictures from shooting tonight.


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Any idea how much poundage you lost backing it out? I'm surprised it didn't make more of a difference.

 

[TheCougar]

Any idea how much poundage you lost backing it out? I'm surprised it didn't make more of a difference.

I don’t, but it felt noticeably easier to pull. I was aiming a bit high to avoid hitting the wagon.


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[Ucsdryder]

From what I’m gathering turning the limbs down and dropping to 100gr made things a lot better? I’d find a 200-250 spine arrow somewhere and see what happens.

 

[TheCougar]

From what I’m gathering turning the limbs down and dropping to 100gr made things a lot better? I’d find a 200-250 spine arrow somewhere and see what happens.

Nope, total opposite, at least from what I can tell. Basically no difference from reducing point weight and lowering draw weight. Bareshafts still way left at 20 and broadheads still left at 40. Tomorrow I’ll try to manipulate my grip and maybe tweak my arrow rest.


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[Billy Goat]

I'd try to determine how much weight you lost from dropping the poundage, I'd back it out further to make sure that it doesn't fix it, but I'm not familiar with those bows so I don't know how far you can actually go. I'm really surprised two turns off didn't fix it. Going to take someone more familiar with those bows at this point. I'm in the camp of setting the center shot to what the manufacturer recommends, maybe slightly further if clearance is needed for larger vanes. Then tune from there, if that's yokes, shims, top hats or whatever. I thought those primes had a paired cam system to help fix a lot of those issues. Haven't messed with one.

Good luck, make sure to post what you find.

 

[TheCougar]

I'd try to determine how much weight you lost from dropping the poundage, I'd back it out further to make sure that it doesn't fix it, but I'm not familiar with those bows so I don't know how far you can actually go. I'm really surprised two turns off didn't fix it. Going to take someone more familiar with those bows at this point. I'm in the camp of setting the center shot to what the manufacturer recommends, maybe slightly further if clearance is needed for larger vanes. Then tune from there, if that's yokes, shims, top hats or whatever. I thought those primes had a paired cam system to help fix a lot of those issues. Haven't messed with one.

Good luck, make sure to post what you find.

To my knowledge, there’s no yokes or shims since it is a parallel can system. There is a “Flexis” which I need to mess with. That’s about the only thing I can do.


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