broadhead tuning question
 

I've been shooting my new AlphaMax35, set at 70lbs, with fieldtips for the last month and today I tried broadheads for the first time. As expected, the broadheads did not group with the fieldtips but I haven't had problems tuning for broadheads before. The broadheads are shooting high (2") and to the right (6") at 30 yards, so I moved my rest away (left) from the bow a little. The broadheads are still shooting right (not quite so much) and the field tips are now shooting to the left. I can't keep moving the rest left because the field tips will be off the target soon. I did some measuring and calculatingand the FOC is 8%. I am shooting GoldTip 350 CAA's at 29 1/2" with a 100gr SlickTrick andthree 2-inch Blazer vanes. According to all the charts, there shouldn't be any problems. The Easton tuning guide said to move the rest left, decrease poundage, or lighten broadhead weight. Does anyone see anything strikingly wrong with the setup? I have been kicking around the idea of trying Rage expandables. Maybe this is a good time to try them.

RE: broadhead tuning question
 

Don't switch to mechanicals when things aren't right with your setup, it'll just create different problems. The Gold Tip website doesn't list any data for those arrows but the spine seems on the light side, so try cranking the bow down to 60# and then try to retune with the slick tricks. Another problem could be with your FOC, 8% is the lowest recomended amount and many go with greater than 15%.If you up the FOC your arrows will definately be too light, see if you can't borrow some heavier spined arrows from a friend. Another thing that you could try is to switch to another fletching. Blazers aren't for every setup, I switched to 3" quickspins and my broadhead flight improved.

RE: broadhead tuning question
 

When you see something like this, you don't want to move the rest opposite the BH's but a lot of the times move towards where the BH's are hitting.

I do this with Bareshaft. So if your bareshaft is hitting 6" to the right, move your rest to the right. If you have to move more than 1/8" past bow center, you need to look into some different spined shafts.

According to OnTarget, your a tad weak spined with that combo. Like I said, I would not move more than 1/8". I would tune the bow to the arrow. Drop down to 64lbs and see what happens.

RE: broadhead tuning question
 

I checked a couple other FOC calculators and they said not to use the length of the broadhead in the overall length part of the equation. If that's the case, the FOC with my setup is 10%. What would happen if I went to 125gr broadheads?

RE: broadhead tuning question
 

FOC is not your issue. If you went another 25gr on the head it would make your setup weaker, then you would have to drop more poundage off the bow. If anything you need to go to 75gr. Don't get wrapped around the axle with FOC.

RE: broadhead tuning question
 

What bugs me about this whole thing is that I used a chart from GoldTip to pick these arrows. The chart shows that if I shoot a 100 grain tip, use a 29" arrow, with a draw weight of 65-70 lbs, I should use an arrow in Group 5 which includes CAA 500. If I use a draw weight of 70-75 lbs, Group 5 arrows should also work. According to the chart, I shouldn't have to use a stiffer spined arrow until I go to 30" with the current draw weight, or I go to 75-80 lbs with a 29" arrow. I guess the only thing thatmatters now is what I see on the target. It's too bad I spent so much money on carbon/aluminum arrows.

RE: broadhead tuning question
 

Hey BigCountry...I have been messing with that OnTarget program. What cam system would the alphamax be considered? It's advertized as a cam and 1/2, but that's not one of the options for bow input.

RE: broadhead tuning question
 

Chart only gets you close. You have lots of tools at your disposal after you use a chart. You cut 1" increments to stiffen, you can change heads from 75gr up, you can make slight adjustments to the rest. Or you can drop poundage, which is my prefered method.

Give this a try....

Scrap what you're trying to do here. Those arrows should be almost PERFECT in your bow, I don't believe the problem is the arrows. Start at 20yds, zero your top pin at 20yds with a FP, then do a walkback tune, 20-25-30-35-40yds, follow what your rest is telling you needs done.... " \ " Rest need to move to the LEFT, " / " the rest needs to move to the right, get everything grouping like this " l ", then go back to 20, make sure your pin is zero'd, and start the BH tuning process. Check out this link.... http://www.archerytalk.com/vb/showthread.php?t=539460
It's probably the BEST step by step rundown I've seen to show someone how to BH tune.