Broadheads not synching w/FPs - Advice?

[Brad NSW]

My broadheads (Exodus 100gn, same as FPs) are shooting low. Other broadheads were even worse and had bigger groups.

See attachment: View attachment 50Yd FP vs Broadheads.pdf
1.7" low with 2" blazer vanes. 5" group. 245 ft/sec average arrow speed.
2.3" low with 4" Raptor Duravanes. 3.5" Group. 234 ft/sec ave arrow speed.

When I shoot a bare shaft, it is lower than the fletched arrows.

I have a 1" nose down tear when paper tuning.

I shoot a Bowtech Carbon Icon at 58lb draw weight.

Three questions:
1. What else can I do to shynch the broadheads to my FPs? My whiskerbiscuit is as high as it will go.
2. Would you shoot the 4" vanes, even if they are slightly slow (they seem a little more accurate)?
3. Are 2" or 4" vanes more impacted by wind?

Thanks in advance for any advice.

 

[Deleted member 20812]

1. Re center your WB. Move your nock point down. Where is your nock point in relation to center of ATA? Usually you should be about 1/4 to 1/8 above this. Check your cams for timing and check your tiller (both limb bolts turned out the same amount).

2. Do you have any helical on your vanes? If not, put some on. Blazer vs. 4" is a moot point if you have strong helical on your vanes. My guess is you don't have any helical, probably only a small amount of offset.

3. Bigger vanes will be subject to more wind drift. I shoot AAE Max Hunters and find the accuracy to be every bit as good as when I was shooting 4" vanes.

 

[jvanhoy]

If you have a high tear move knock point down.

 

[Epfd217]

Your issue is with tuning, not broadhead or vanes Fix your tuning issues first. Look up the procedure for paper tuning. If you have a 1" tear than you need to adjust your nocking point, especially if you've maxed out the adjustment in your rest.

Frankly, I would throw your bow in a vice and start from scratch. Sounds like your bow and shooting is pretty decent, so I would reset the rest, getting it shooting perfect through paper, then set your FT setup and finally do broadheads. It shouldn't take long since it sounds like you know what you're doing.

I offer this advice because I went through a very similar experience this past spring. I messed up something with my rest I believe and needed to start over. It was worth it.

 

[Epfd217]

As far as the size of vanes, thats up to you. The data you discovered is similar to most data collected on the issue. Larger, heavier vanes gather more air and tend to steer (and stabilize) broadheads better, but yes, they are slower. Its up to you if the tradeoff is measurable enough to worry about.

 

[Brad NSW]

It's pretty frustrating. I lowered the nock point (very close to an inch) till I had perfect paper (no tear for 3 shots). This put the nock point centered between the limbs.

Unfortunately, the arrow was about 3-5degrees angled up when nocked in the whisker biscuit (not drawn). This didn't seem right! After some big sight adjustments, the broadheads still shot low. I weighed the FPs and BHs (within 1/2 a grain of each other).

Moved nock point back up. More big sight adjustments and the BHs are still low.

Back to where I started after shooting about 100 arrows.

I don't have a vice, so I guess it's a trip to the shop next weekend to see if they can figure out what I'm doing wrong (form) or do something with the bow itself.

Thanks for all the replies. I think I will stick with the Blazer 2" vanes. I do have helical on them and that seemed to help bring the broadhead groups a bit tighter, especially with the 4" helical. Tried some low profile 3" and they seemed to make things a little looser.

 

[Deleted member 20812]

Did you check the tiller? That's an easy one before you take it in.

How old are the strings/cables? You could have stretch in them underneath the serving where one is beginning to fray.

Does the insert in your WB need replaced?

 

[jvanhoy]

Did you check the tiller? That's an easy one before you take it in.

How old are the strings/cables? You could have stretch in them underneath the serving where one is beginning to fray.

Does the insert in your WB need replaced?

Good advise. Check all your specs if your string has stretched and your axle to axle is off your bow will never shoot right

 

[Brad NSW]

Thanks JLS,

Checked the strings. Lower one looked a little worn under the serving. It's my 1st bow and not too old but I've been shooting A Lot!.

So I made a few adjustments to the bottom tiller screw. Brought the paper tuning in so it was almost perfect.

Shot three (5 shot groups w/1 broad head/4 field points) at 40 yds. Broadheads were mixed nicely in each group.

Shot three more 5 shot groups at 50 and the broad heads were the lowest arrow in the groups but still pretty tight (4-5 inches, centered on the bull).

I should probably take it back to the shop I bought it at and have them look at the strings.

For a newbee like me, forums like this are a great resource. I want to have eveything dialed in by Sep for my first archery try on elk/deer!

 

[Deleted member 20812]

You're more than welcome. Check your limb bolts and make sure they are both in about an equal amount. If they are not, then the tiller adjustment is masking something else like a stretched cable or limb damage.

I shoot quite a bit too, and figure on a new string every other year.