Tuning and broadhead weights

Critr-Gitr · 05-17-2006, 08:11 AM

I have some questions but I will give my setup first.

2005 Bowtech Tomkat set @ 58lbs and 28.5"
CX eliminator 250's with 125 grain tips
shoot with a release, string loop, and a WB

The question is, I would like to go to a 100 grain tip instead of the 125. Last night I shot a limited test as it was starting to get dark, and the results were not definitive, but it seemed the 100 shot slightly tighter than the 125s my bow was (supposed to be) tuned for. My plan had been to drop the tip weight and increasedraw weightto 60 to compensate for the change in spine. As it appears right now the increase in draw weight is not necessary. What are you guys thoughts on this?

newman1 · 05-17-2006, 11:20 AM

If the grouping is still acceptable than go with it.

Bulzeye · 05-18-2006, 11:34 AM

Forgive me, but tune is not measured by group size, but rather by how true the arrow flies while in the air. The end result of a good tune will be tight groups, but tight groups do not insure that they are flying properly.

Have you tuned with bareshafts? and broadheads if you hunt?
If not, tune it up first. Odds are that your current setup can achieve a better tune with one point weight or the other. You may still need to play with the draw weight a bit to get it dialed in perfect.

05-18-2006, 01:18 PM

For me, the rule is broadhead tuning. That will tell the tale. IMO. Use soemthing simple like thunderheads, nothing fancy that spins or does something crazy. Make sure you spin tune the arrows and see where they hit in reference to your field points.

Critr-Gitr · 05-18-2006, 03:10 PM

Sorry, I went a little bit light on information there and perhaps didn't phrase my question correctly. The bow is in tune currently at 58# and with 125 gr tips. It will group broadheads in 3"-4" groups at 30 yards, at the same poi as my field tips, and about the same accuracy level. This is with either thunderheads or 4 blade stingers. I don't get to shoot as much as I should, and those group sizes probably reflect the shooter and not the bow.

All other things being the same, decreasing tip weight decreases dynamic spine of the arrow, and increasing draw weight increases the dynamic spine of the arrow. Would increasing the draw weight a couple of pounds tend to offset decreased tip weight as far as dynamic spine of the arrow is concerned? Really it is a moot point, because my string has stretched and I should probably re-tune anyways,I suppose it ismore of a theoretical question, but I was just curious.

05-18-2006, 07:00 PM

What I am trying to say, if the new broadheads (100gr) start grouping to the left of your field tips, you know, your too stiff spined now. If not, then your fine. Or you were on one side of the spine where you might have been under before but it was subtle before. So then you can increase your bow wieght until they start grouping together again.

Critr-Gitr · 05-19-2006, 06:30 AM

Okay, gotcha. I understand what you are saying, thanks.

Bulzeye · 05-19-2006, 11:27 AM

Yeah,

If it was tuned up good, and you change point weights, you'll have to change something. Draw weight is one thing that can compensate.
In fact it is one of the easiest things to change to make the final minute adjustments, when you get really close to perfect. Sometimes a 1/4 turn or the bolts is all you need for a 6" difference in POI at 30 yds.

Good luck.