Broadhead Tuning

Threw broadheads on my arrows last night to see how they're flying. I was consistantly shooting 4"-6" to the left of my field tips, I moved my rest but no matter what I did I consistantly was shooting 4"-6" to the left of my field tips. I then used a bare shaft and had similar results, but worse. I then was shooting 8"-10" to the left of my field tips. I already did walk back tuning and was consistantly holding a good group from 15 - 80 yards so that tells me my rest has to be pretty darn close. If I'm right I then have a form, spine, or contact issue. I'm mostly concerned about a spine issue so here is my set-up.

Bow: Elite GT500 set at 70lbs 29" Draw
Arrow: Easton Axis ST 340 28" Long
Head Weight: 125 Grain

Any idea if this is properly spined or if there is anything else I have to look at. I feel I have decent form and I've been shooting real consistant with field tips. I'm a little lost, thanks for any help. Paul

 

Here is what i would do , get your field points shooting dead on , if you find you dont have any contact issues take a turn out of both limbs , you can steer that broadhead where ever you want it by your poundage and you wont loose any KE , Your spine is fine , make sure all your broadheads spin test without no wobble , stand your heads up on there points cup your hand around your arrow shaft towards the middle of the shaft and spin it like a top , see what you got .

 

Seems like a stiff spine reaction to me. Turning down the DW would only make it worse. You could always buy a few heavier (than 126 grains) field points just to see if a stiff spine is the problem. They only cost .50 or so and you only would need 2-3.

 

Ahh , i got ahead of myself when i was typing , i hadnt had my coffee yet , what i ment to say if possible you can crank your limb bolts in or out and it will steer your broadheads ,

 

Just a thought, and I am no expert by the way. What would lengthening the arrow do? It seems you could make the arrow something like 29" or 30". That would weaken the spine too. If your drawing 29" already you should have no problems going a little longer on the arrow. Buying new arrows is probably something you dont want to here, but this could be a fix also.

Correct me if I'm wrong guys, no expert here, just a thought.

 

I found this chart on broadhead tuning: This would indicate I have a stiff spine problem. If I get higher grain field tips would the field tips impact then change? I feel like I'd have to increase the broadhead weight to make any difference. I could be wrong.

 

Thanks for the advice, I'm in need of some more arrows so I may try to increase the length also. I'm going to try somethings mentioned and see what happens. I'll probably have more questions come monday, Thanks everyone! Paul

 

Right , with that chart is what i ment if shooting to the left increase poundage if possible , i know i said decrease that was a mistake on my part i know better , my brain wasnt functioning yet after i just woke up ......lol

 

If you get your new arrows cut to 30" then they will probably be a touch weak spined and then all you would have to do is turn down your DW a bit to tune right up. If you find yourself turning down the DW too much then get 1/2 inch cut off of a couple arrows at the nock end, increase the DW and see how it tunes with a BH on one and a field tip on the other. If the DW is still too low for your liking cut another 1/2 inch off of those two arrows and see how that does.

It is always easier to trim an arrow that is too long because gluing extensions on arrows that are too short is really hard to get right .

 

I was having a heck of a time getting my broadheads and field points to group together also. But I had the opposite problem, my broadheads were always 6" to the right of my field points. I tried everything. I was using 125gr tips, so I put on some 100gr tips and they shot perfectly. Is that the correct way to "fix" the problem? Or would I be better off turning down the poundage? Or are they both acceptable? I have a Bowtech Destroyer 350, ~70#, 29" draw. I am using Victory V-Force 1 300 arrows cut to 28".

Thanks

 

WIWhitetail, If I'm understanding all this, you would have had a weak spine. So your options would have been to lower your poundage, lessen your tip weight which you did, or shorten your arrows. All of or any combination are accepable changes. Since I have a spine that's too stiff, my hands are tied. I'm picking up 30" arrows today, an increase of 2", so I hope either my spine is right on or too weak so then I have the options you had. If my bow wasn't maxed, and the tip pretty much as heavy as you can go, I could have adjusted a lot easier. I'll see how it all goes!

 

Some things to know about that era Elite;
-They tend to like a weaker spined arrow than typical.
-The rest should be 13/16 - 15/16th of an inch out from the riser.
-If you're getting out 15/16ths or beyond, try flipping the limbs top for bottom. (I did this as a last resort on one of my Z28's and BAM it suddenly tuned in perfect... go figure.)
-To do fine tuning on these bows you need a draw board to check the cam synchronization. Be sure that the cams are timed to one another. (It makes a big L/R difference).
-If the cam rotation is a little off from spec. don't sweat it too much (one of my Z28's is dead nuts and the other is out and they both are tack drivers with perfect bareshaft and broadhead tune), but they are both right on for ATA, brace and cam sync.