Turning down the poundage to achieve better arrow flight?

PhillyB

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Has anyone ever turned their bow down in poundage to aid in broadhead tuning?

As mentioned in other posts I am struggling with BH tuning for a fixed blade head.

I am shooting my Alphamax at 72 pounds traveling at 289 fps.

Is it possible less could be more is getting my BH's and FP's to group?
 

GRAYLIGHT

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Apr 17, 2012
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PhillyB, Your poundage and fps may not be what you want to change. I would first take a good look to make sure your arrows are spined properly for the job, then look at your broad head. Start off with tuning your bow the best you can to achieve a bullet hole with a bare shaft. Then I would make sure to square your arrows and even square your inserts after installed, that way you are screwing in your broad heads flush and true.

Pick a short cut on contact head like the Slik Trik, G5 striker or Innerloc stainless extreme. Spin test them and you should not have any problems... The focus should be emphasized on a properly tuned bow i.e. nock point, cam lean, tiller ect., ect... Achieve a proper tune and the above listed broad heads will fly great with your set-up.

Set up your arrows correctly, go as far as using the same bitzenberger fletch jig for each vane of your arrow, so that every vane is orientated the same... Using any other jig, can yield different results even if it appears set up to be the same helical, same orientation... You can even go as far as to float your arrows in water to see where your arrows are spined at and make that your cock up vane, so that each arrow leaves the string the same as the last lol... I don't go that far but I know folks that do.

If you shoot 70 plus yards, weigh your arrows 10 grains can equal + or - an inch on the target down range... I cannot express this enough... Square your arrows...

Good luck!
 

Darin Cooper

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If you're under-spined, i.e. .400's with that setup you might get your groups to tighten up by reducing draw weight. As long as the bow is tuned well that can actually be a pretty good test to see if that's the case. The G5 arrow/insert squaring tool is excellent advice - highly recommend it with fixed blade broadheads. Let us know what you find... What arrows are you using?

Coop
 

JNDEER

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Check spine of arrow.
Check vane contact.

If those are ok, than this is what I have found works for me.

I never paper tune anymore. Here's what I do.
1. set my bow up for centershot and my arrow 90* to the string.
2. sight the bow in at 10 yds
3. shoot one arrow with FP at 10, 20, 30, 35, 40, etc and check for vertical
stringing. If not adjust rest accordingly and repeat.
4. Shoot a FP then a BH at 20 yds and 'chase' the BH with the FT by moving the rest in the direction toward the BH. (Tip: when you start getting close, either at 2 different aiming points or shoo the BH first. It saves your fletching.)
5. Move back to 30 or even 40 yds and do the same thing. Remember in steps 4 and 5 you only move the rest in 1/32" increments.
 

RosinBag

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PhillyB lots of good advice. But for your question, turning your poundage down will only help if your arrows are spined incorrectly. Without knowing your set up all the advice is good for general tuning. I would say though that most bows will shoot broad heads well if tuned correctly. Good luck.
 
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PhillyB

PhillyB

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Hey guys I appreciate all the input. My arrows are spined right and the bow is tuned. I have squared all the arrows with the G5 ASD and spin test them. That is why I was so frustrated in the inconsistency of my BH flight.

Tonight I tipped myself off and figured it out. The tied in nock sets had come loose allowing the D loop to slide a bit and pinch the nock. I believe the nocks were being pinched a little and not getting a clean release. I retied the nock sets and ties a new d loop. Out to 30 yds I was golden. That is all I can shoot at the house. Hopefully it holds true at the range at longer distances.
 

Brandon Pattison

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If your arrows are spined in the gray area between two sizes adjusting your poundage might do the trick. Be sure that the bow's sight is perfectly level with the bow. You need to find a good 4' level and get a spot where you can put your bow up against it to zero your sight. I used to use a 2nd and 3rd axis sight but found they were weak, even the best ones. I have a door in my house that I use and use machinist's shims to make mine perfect. You also have to level the bow as part of your shot process. All of the above is good intel though. You can also try traditional style broadhead tuning by shooting both broadheads and field points at the same target and adjust from there. Gold Spot has a good demo on this. Just remember that your arrow has to do its thing before it stabilizes.
 

dotman

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Lot of great advice, I have always heard your bow will shoot it's best at the max poundage for the limbs. I would play with your arrows before messing with your poundage unless it is toi hard to control.
 

Darin Cooper

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Lot of great advice, I have always heard your bow will shoot it's best at the max poundage for the limbs. I would play with your arrows before messing with your poundage unless it is toi hard to control.
This is true in large part - here's a few factors to consider off the top of my head why it's generally desirable to stay at or near peak weight:

Some bows maintain better limb & pocket alignment when bottomed out. I like Hoyt's pocket system for this reason - locks down alignment to riser regardless of how far backed out). Not a big deal until you fall down or your bow tips over, etc... I have seen some bows move 6" impact left and right just by tapping hard on a top or bottom limb.

String tension decreases at brace height more rapidly as parallel limb bows are backed out. This can change the way the bow tunes slightly as the string oscillates differently and has less driving force to stay on course (in line with the arrow) - this can make your shot more susceptible to torque. May require new center shot alignment as torque on the bow changes - also effective spine requirement will change as you reduce draw weight (maybe for the better or worse). It's generally easier to get a broadhead to group on an arrow that's too stiff rather than too weak.

Some bows will get louder as the string "twangs" worse when string tension goes down, some may actually get quieter if they have extremely high string tension at brace height. Brace height changes slightly on some bows as they are backed out so the power stroke can decrease (not really a factor on parallel limb bows).

Pre-load on the limbs decreases as you back them out. Limbs perform best (respond quicker), when more highly stressed. Too much stress leads to premature failure though.

I wouldn't worry about a few turns on the limb bolt - This is typically more of an issue when you're backing a bow out 7-10+ pounds. Most popular bows are designed to work well over their given adjustment range (+/- 10#). I usually tiller my bow slightly by backing off the top limb. This alters the grip angle slightly and works better for me personally and I haven't seen any ill effects on my target or hunting Hoyts. Your mileage may vary.

Coop
 
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PhillyB

PhillyB

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I am shooting Beman Hunter Elite 300 spine with Slick Trick Magnums. I ordered some Wac'em exit heads to try as well. Hope to get those in soon.

When I had the bow tuned, it was shooting right at 290 fps. With all the calculators I can find, I have about 72 lbs of kinetic energy.

As I said, I can shoot darts with field tips. I am pretty solid out to about 80 yds. I will know how the BH's shoot at that distance this weekend. Out to thirty yards they are flying great, but that really isn't enough distance to know what is happening when the arrow is in thebairna little longer.

Also, I have been curious about FOBs so I ordered a tube to try out. It will be interesting to see what effect they have on overall flight.
 

JG358

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Also, I have been curious about FOBs so I ordered a tube to try out. It will be interesting to see what effect they have on overall flight.
I never really noticed much difference when I tried them. They flew to pretty much the same POI as my arrows fletched Quick Spins and Blazers.
 
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