Shots are breaking down and to the right

[WapitiTalk1]

Confirm correct spine and tune your bow.

[MAVsled]

Confirm correct spine and tune your bow.

yes, this! 
if something like 20gr extra in the nock throws off arrow flight, you need a stiffer spine!
then tune you bow, rest, etc to this new arrow spine-arrow set up.

[andersonjk4]

I’m fairly new to archery, but doesn’t adding weight to the back of an arrow make it behave stiffer?

[CP]

I may need a stiffer arrow. 

31” arrow, 100g point, 70lb draw = 250 or 300 spine depending on whose chart I use.  I’m shooting Beman ICS – 340s.

I’ve been shooting these for years without problems until I put on the lighted nocks.  And these nocks are only 13g heaver.  Seems kind of touchy.

[MR5x5]

I’m fairly new to archery, but doesn’t adding weight to the back of an arrow make it behave stiffer?

This.  Adding weight to the rear acts to increases the "dynamic" spine.   Normally being a little to stiff should not be a problem (if you know what I mean ).

Me thinks something else is going on....

[andersonjk4]

Are the lighted nocks tighter or looser on the string than your previous nocks? 

[CP]

Are the lighted nocks tighter or looser on the string than your previous nocks?

No, pretty much the same.

[lamrith]

I may need a stiffer arrow. 

31” arrow, 100g point, 70lb draw = 250 or 300 spine depending on whose chart I use.  I’m shooting Beman ICS – 340s.

I’ve been shooting these for years without problems until I put on the lighted nocks.  And these nocks are only 13g heaver.  Seems kind of touchy.

340 sounds a bit lite for 31" arrow and 70#.  They may have been working, but according to the chart I just looked at you should be running 300's.

THAT SAID:
It may go beyond "simple" spine issue if your FOC was marginal you just added weight to the back making FOC no longer good.  The tail of your arrow is too heavy versus the front, that will make the arrow wobble and not fly true.
The good news is you are shooting 100grn tips.  Before you go out and buy new arrows, a simple fix/test will be to put the lighted nocks in and then also install a 125grn tip and try it.  This will add weight and make your arrows drop sooner so will require some sight adjustment, but may get your FOC back were it needs to be so the arrow is flying straight again.  Lot cheaper test than buying new shafts with stiff spine when you are not sure what the actual issue is.

If you want to try stiffer spine check out sportsmans warehouse.  They have their own line of Vital Impact arrows that are made by GoldTip, they are comparable to the $70+ goldtip arrows but not paying for name...  ~$37 for 6 arrows with vanes, inserts and nocks.  Staff in Archery Dept will cut them to length for free when you buy as well.  That is honestly all I shoot, they shoot straighter than I do, are very straight and don't hurt the wallet when you break one going thru an elk.  Even if you like the higher en, it might be a good investment to try out stiffer spin before you buy fancy arrows and can keep them around for basic practice..

[dreadi]

This thread has opened my eyes to my own problems.

My shots with broadheads and illuminocks we’re dropping quite a bit, as they do every year. So I took off the Illuminocks and put the factory nocks back on it got much better. So now I’m going to be trying lighter broadheads and I’m going to experiment with stiffer spine arrows and different weight broadheads. 


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[HAGEMANIAC]

I may need a stiffer arrow. 

31” arrow, 100g point, 70lb draw = 250 or 300 spine depending on whose chart I use.  I’m shooting Beman ICS – 340s.

I’ve been shooting these for years without problems until I put on the lighted nocks.  And these nocks are only 13g heaver.  Seems kind of touchy.

31" arrow, but what is your draw length? Cut down that arrow and it will stiffen up the spine.

I'm 28.5in draw, but arrow carbon to carbon is cut 27.5, but I shoot a drop away and am comfortable with my broadhead being behind front of riser.

[blackveltbowhunter]

CP, Im curious what fletching and how many and any other weight to the back of the arrow? Using GT calculator ( only one i can really estimate your specs with without measurements) and assuming a Blazer type vane in a 3 fletch with no wrap, the original S nock in that arrow your FOC comes in at 8.5 percent. Switching to the lighted nock which you say is 13 grains heavier bumps you down to 6.3 percent on your FOC. In this case that 13 grains is a BIG difference.

My somewhat educated guess is that you likely have a couple things at play here with the nocks. Assuming nothing crazy wonky with the bow, arrow spine being lower on my list of things to check. A)  The lighted nock is dumping your ( arguably) already marginal FOC into clearly not recommended territory.
B)  Nock fit/arrow release is not PERFECT and the low FOC highlights this very well. Higher FOC arrows tend to forgive those slight release variances much better than lower FOC rigs as it keeps the point of the arrow from "floating" around as much.

The quick fix is dropping the lighted nock and bumping to 125 grain heads. This puts you into the 10 percent FOC category. Still low, but much improved over the lighted nock scenario. I generally like to see 11 percent minimum for hunting setups. Ultimately if looking for a more forgiving setup with more options I would look into an arrow overhaul that bumps those numbers up. Likely a stiffer spine, with at least 50 grains in the insert, and probably a lighter GPI shaft or cutting back as short as possible to get that FOC number up a bit.

Good luck!!

 

[CP]

The arrows are standard Beman ICS hunter 340s, with 3 small plastic vanes. 

Right now, with the original nocks back on, the arrows are flying straight and they are sticking in the target perpendicular to the target face.  With only 2 days to the opener I’m going to keep things as they are and after the season, I’ll try to figure out the lighted nocks. 

I appreciate all the advice.   I like practicing with the lighted nocks as they provide instant feedback.  I can see the arrow track through the air and see where it sticks the target.  I do want to get them dialed in eventually. 

[lamrith]

CP,
This is something I have used to help correct FOC while keeping your existing arrows.  Provided your spine is ok these would be a way to add weight to the nose if the 125grn heads are not enough, I have used these in the past to maintain FOC
GoldTip FACT Weight System