Lighted Nocks Changing Point of Impact

[Todd_ID]

I wanted to write up a bit of factual information about the lighted nocks since I was one asking for them.  I knew the Front of Center (FOC) would be changing since it adds more weight to the back of the arrow, and I knew the point of impact would change.  Now that I've used them for a while I have some data to pass along.

Easton Axis 340 black 9.5 gpi at 29.25" length from bottom of nock V to end of cut carbon
X-Nock standard is 9 grains
Nockturnal X Lighted Nock is 20-21 grains
3 Blazer fletched
4" of arrow wrap

With 125 grain heads:
Without lighted nocks: 450 grains, 12.8% FOC
With lighted nocks: 462 grains, 11.5% FOC

With 100 grain heads:
Without lighted nocks: 425 grains, 10.7% FOC
With lighted nocks: 437 grains, 9.4% FOC

The end result was that with the lighted nock installed I saw a point of impact shift of 7" higher at 40 yards than without them installed.  My bow is tuned to get broadheads and field points impacting at the same point.

To create the same weight as the lighted nocks, so I don't have to use the battery life, I found that 2.5" of 18 gauge automotive wire folded in half and glued into a standard X nock is the same weight as the Nockturnal nock.

The Nockturnal nocks I bought were red.  I can't see the flight in the full sun, but overcast days are ok.  Morning and evening they shine stellar.  One of the nocks I got had a sticky switch, but I used my pocket knife to run the switch on and off about 30 times, and it started working correctly.  The rest of the nocks worked as advertised.

[IBspoiled]

Good info thanx

[brianb231]

Just to add to this. I shoot a Hoyt Spyder 30 set at 62 lbs and a 29 in Draw. The arrow is a 392Gr Carbon Express maxima 350 hunter with a 100 gr tip. I found that by using the nockturnal lighted insert it shot two inches lower than my traditional nock setup.  For those that are interested.

[RadSav]

Todd - Did you run a set of calipers on the throat and height(c/s) of the two different nocks?  I've been meaning to get out my trigger pull gauge and test the Nocturnals against the MicroLite nocks I've been shooting, but I seem to have misplaced it.  I know different nock c/s and throat dimension show large differences on point of impact for me.  Makes me wonder if that might have something to do with your results and brianb's results being different.  If I ever find my dang trigger gauge I will let you know what I find out.

[Todd_ID]

I haven't checked the physical dimensions yet.  I think the length is the same, but the diameter is certainly different.  The Nockturnal does not fit into the Easton X-nock turning device.  The base of the nock is thicker, but the legs from the V back are the same as an X nock.  I.e., The stuff that makes any contact with the string is the same.

[RadSav]

I haven't played with the X-Nock version.  Only the "S" version.  Maybe I'll have John send me a few "X" and see what I see in comparison to Easton and Bohning's nock.

[Old Dog]

Great info guys.    Keep it coming. 

[Bowcrazy]

    Shooting 55/70 carbon hunters with the green nockturnals and a 125 grain 4 blade slick trick. The new nocks and broadheads fly identical to my regular nocks and field points. The nockturnals look really bright and turn off easy. I am shooting a PSE Stinger @ 70 lbs. and I am shooting just as well as my buddies with Matthews bows.


Bowcrazy

[turkeyfeather]

So far out to 30 yards I haven't had to make any adjustments with the lighted knocks. I am still in the bullseye.

[demontang]

Mine seem to fly the same so far. I can put a broad head lighted nock next to my regular nocks out to 50yds.  I was just playing with them last night

[mountainman]

Ditto here. No change in grouping

[Whitetail freak]

I found that the nockternals shoot different out of mine to, I think it has something to so with the little knob in the nock. I now shoot lumenoks, there alittle less simple but once they are set they are 10x brighter and don't change arrow flight at all out to 120 yards. 

[nocklehead]

Mine seem to fly the same so far. I can put a broad head lighted nock next to my regular nocks out to 50yds.  I was just playing with them last night

I have nocturnals as well and dont have a change in group, carrying and shooting both lighted and not in my quiver right now and both hit the same place.

They sure look cool right before dark, I will definately be using these in the evening hunt, even on my small game arrow.

[CoryTDF]

Just bought two packs of these for my elk hunt. They seem to hit same as my regular nocks. Had one that was really sticky and nearly broke it trying to turn it off. They are still %1000 better than Lumenock as they ALWAYS turn on and have yet to shut off on impact. I had terrible trouble with Lumenocks in the past doing night shoots at 3D shoots and whatnot. They always turned off.

[2MANY]

I see the light!!

[jathtech]

Saw this post and has some theories as to why some people were experiencing a shift in impact location, while some are not.

First, whatever the grain difference is, (12 grains?) it should really be nominal.  In theory however, it might effect  the flight of the arrow ever so slightly.  The OP is way beyond what I would expect however.  Here are my theories as to why to  nocks cause this:

1, Nocking point.  If the nocking point is lower, it could cause the arrow to "bounce" off the arrow rest more with the heavier nock, accounting for its higher impact point.

2, Wind resistance.  You're going to have a slightly slower arrow, but it going to maintain its speed better than a lighter arrow.  This may cause the lighter arrow to slow down beyond where the slightly heavier arrow is, and drop more out to 40 yards. 

3, harmonics.  Sometimes, you just get things tuned just right where the vibration is perfect, and the least amount of wind resistance is achieved. 

4, String grab.  It's possible that the nocks are grabbing the strings differently, either tighter causing it to hang on to the string too long, or looser causing it to bounce off of the string and not get the full energy. 

Keep in mind, these are just theories, and not based on experience as I am new to archery (however not to marksmanship, or physics).

[Todd_ID]

4, String grab.  It's possible that the nocks are grabbing the strings differently, either tighter causing it to hang on to the string too long, or looser causing it to bounce off of the string and not get the full energy. 

This one was the problem... The Easton X nocks had a larger string gap than the Nockturnal X nock, so it was staying on the string longer.  I don't remember the actual difference off the top of my head, but it was substantial (something like .030" or .040" difference).  I filed the inside of the Nockturnals to the same internal dimensions as Easton's, and the problem went away.

[Russ McDonald]

Now that this came up again I thought of something mine did.  My groups at 20 and 30 yards we unchanged from none lighted nocks to lighted but when I went out to 40 and 50 there was a change.  It was shooting at least 2" lower with the lighted nocks.  Dead on center but lower.  Just dialed in the correction and it is on. 

[TommyH]

Good info here, I was hesitant to use these. I didn't want to have to change my set up when it was doing so good.

[RadSav]

I wish all pro shops would buy a trigger pull gauge.  Would save a lot of headaches for archers with these issues.  Back in my target days it was surprising to see how much each cavity in a mold would change.  I ended up sorting nocks by the cavity number molded into the nock.  Some do it these days some do not.  With the pull gauge it makes life much easier.  If you shoot a lot it is also a good practice to keep a shot journal for each arrow/nock.  Find out when impact points change by how many shots it has taken.  Back then aluminum arrows only had so many shots before spine would start to change as well.  Doubt that is an issue with carbon, but I no longer keep journals as I rarely shoot enough these days.

Todays nocks are polycarbonate instead of cellulose-butyrate like they were in the old days.  Polycarb is stronger, wears out at a slower rate but is stiffer and shows impact differences with less throat width change.  Watch them closely if you see impact points rise or fall.  Sometimes if you have one arrow that doesn't group with the dozen you can recover it with a simple nock change instead of sending it skyward off the mountain top

[bowhunterforever]

I wish all pro shops would buy a trigger pull gauge.  Would save a lot of headaches for archers with these issues.  Back in my target days it was surprising to see how much each cavity in a mold would change.  I ended up sorting nocks by the cavity number molded into the nock.  Some do it these days some do not.  With the pull gauge it makes life much easier.  If you shoot a lot it is also a good practice to keep a shot journal for each arrow/nock.  Find out when impact points change by how many shots it has taken.  Back then aluminum arrows only had so many shots before spine would start to change as well.  Doubt that is an issue with carbon, but I no longer keep journals as I rarely shoot enough these days.

Todays nocks are polycarbonate instead of cellulose-butyrate like they were in the old days.  Polycarb is stronger, wears out at a slower rate but is stiffer and shows impact differences with less throat width change.  Watch them closely if you see impact points rise or fall.  Sometimes if you have one arrow that doesn't group with the dozen you can recover it with a simple nock change instead of sending it skyward off the mountain top

Don't know really what your talking about but i'm glad you joined this site those few words I don't understand

[swift]

Thanks Rad , Great info !!!

[JJD]

29.5 " Carbon x maxima hunter 350, with accunocks, 100 gr Striker broad heads.   Draw weight at 62 lbs
Chrono at just under 300fps.
 Nocturnal "S", shoots less than 1 inch low (average) at 30 yds

[RadSav]

29.5 " Carbon x maxima hunter 350, with accunocks, 100 gr Striker broad heads.   Draw weight at 62 lbs
Chrono at just under 300fps.
 Nocturnal "S", shoots less than 1 inch low (average) at 30 yds

I was given a sample of the Accunock a few years ago.  Looks pretty neat, though the technology is older than one might think.  Seems a guy gave me a sample back around '93 or '94 with the same principle though I do not know what happened to him.  Guess it could have been the same guy.  I have yet to shoot an arrow with one.  I'm intrigued enough I might give them a thorough work up this off season since the new Carbon Express nocks are horrible!  And I am just about out of my Easton Micro Lite and Old clear CE.  Was thinking I might have to go back to shooting ACC's just so I could get the X-Nock.  Was that or make my own X-Unibushing for the Carbon Express shafts.

1" difference at 30 yards changing nocks and adding the extra weight.  That's not bad at all in my book   Do you know what you ended up in FOC?

[sakoshooter]

I've been really hesitant to try any illuminated nocks but after reading about simple minor point of impact changes, I might have to find some X Nockturnals. Especially after looking hard for my arrow from my blacktail. Finally found it but it would have been obvious with a lighted nock. With late elk coming up, days are going to be shorter and darker as winter moves in. A lighted nock might just be a smart move.
According to this thread, Nockturnals seem to be the best - Any other opinions as far as durability, reliability, etc?

[RadSav]

I've been really hesitant to try any illuminated nocks but after reading about simple minor point of impact changes, I might have to find some X Nockturnals. Especially after looking hard for my arrow from my blacktail. Finally found it but it would have been obvious with a lighted nock. With late elk coming up, days are going to be shorter and darker as winter moves in. A lighted nock might just be a smart move.
According to this thread, Nockturnals seem to be the best - Any other opinions as far as durability, reliability, etc?

I have found nothing that compares to the Nockturnal.  But you do need to make sure the switch moves freely.  Some that are sticky will not group with the others.  DO NOT TRY TO OIL THEM!  Just work the switch on and off until good and free.  Usually just a bit of flash in the holes.  The flash/burrs will break off if you work them a little.  I do still think in most circumstances stepping up to a heavier broadhead is advised.  Shooting on the range in good weather is vastly different than shooting in the field in not so perfect weather.  If you have poor FOC you will find that one out sooner or later.  Better to error on the side of caution than to screw up the shot of a lifetime to save a couple FPS or a few bucks on new broadheads.

[sakoshooter]

Rad, I'm just over 12% FOC with my Axis 300's and 125gr broadheads now. Putting on a Nockturnal would certainly change that but I really don't want to go to a 150gr broadhead. My total arrow weight now is 480grs and penetration is excellent. Accuracy is super based on our discussions earlier this year when I was trying to make 340's work. Speed is 270fps according to my Pro Chrono. Helical Blazers. Giving up some speed but accuracy and forgiveness is way more important to me.

[RadSav]

If you are 12% now I don't think it should be too bad.  But I no longer have your numbers so just guessing on that.

[sakoshooter]

If you are 12% now I don't think it should be too bad.  But I no longer have your numbers so just guessing on that.

70# Z7 @ 28.5" draw. 28" Axis 300's, 125gr Slick Trick Viper Tricks, 3 fletched w/Blazers - pink ones ol buddy.
I could probably add a 1/2" to the shaft length to overcome the lighted nock added weight and come close to keeping the FOC the same as long as they'd still broadhead tune as I suspect they would.

[RadSav]

Adding arrow length actually makes FOC worse.  Going shorter makes it better, but stiffens up the shaft rapidly.  So I would leave length where you are at.  You should still be at about 10.5% FOC with the Nockturnal nocks.  So I don't think you should see any problems as long as things are tuned well.  If you weren't already at 12% then you would experience some issues.  But, with that 125 grain point you should be just fine I would assume.

[JJD]

29.5 " Carbon x maxima hunter 350, with accunocks, 100 gr Striker broad heads.   Draw weight at 62 lbs
Chrono at just under 300fps.
 Nocturnal "S", shoots less than 1 inch low (average) at 30 yds

I was given a sample of the Accunock a few years ago.  Looks pretty neat, though the technology is older than one might think.  Seems a guy gave me a sample back around '93 or '94 with the same principle though I do not know what happened to him.  Guess it could have been the same guy.  I have yet to shoot an arrow with one.  I'm intrigued enough I might give them a thorough work up this off season since the new Carbon Express nocks are horrible!  And I am just about out of my Easton Micro Lite and Old clear CE.  Was thinking I might have to go back to shooting ACC's just so I could get the X-Nock.  Was that or make my own X-Unibushing for the Carbon Express shafts.

1" difference at 30 yards changing nocks and adding the extra weight.  That's not bad at all in my book   Do you know what you ended up in FOC?

Will measure out foc tomorrow.  Don't mean to get off subject, but the accunocks did get me another 2 to 3 fps over the carbon x nocks.  They are however, fragile. A few dozen shots and one part or another breaks.  Not sure they are worth it.  As mentioned the carbon x nocks leave some to be desired.

[buckfvr]

ONE WORD.........  Arrow Dynamics Orange Nitro Stingers..........FOC ?Forgetaboutit..............

[sakoshooter]

Ya know Rad, that most important thing is that they'd look cool if I ever got to shoot something, LOL.

[coachcw]

nocturnals fly great for me no change out to 70 yards

[RadSav]

Ya know Rad, that most important thing is that they'd look cool if I ever got to shoot something, LOL.

It's really cool when you miss   I did that on a buck up in BC.  He saw that lighted nock and walked over to it trying to figure out what that dang light was.  He was so confused by it he stuck around long enough for me to put one in the right spot 

[sakoshooter]

Ya know Rad, that most important thing is that they'd look cool if I ever got to shoot something, LOL.

It's really cool when you miss   I did that on a buck up in BC.  He saw that lighted nock and walked over to it trying to figure out what that dang light was.  He was so confused by it he stuck around long enough for me to put one in the right spot 

Maybe some Tinks #69 dabbed on the nock might help also.

[RadSav]

Ya know Rad, that most important thing is that they'd look cool if I ever got to shoot something, LOL.

It's really cool when you miss   I did that on a buck up in BC.  He saw that lighted nock and walked over to it trying to figure out what that dang light was.  He was so confused by it he stuck around long enough for me to put one in the right spot 

Maybe some Tinks #69 dabbed on the nock might help also.

Now you are talking   One day I will tell you a story about my evening with Tink and his daughter at the Houston Red Lobster.

[JJD]

29.5 " Carbon x maxima hunter 350, with accunocks, 100 gr Striker broad heads.   Draw weight at 62 lbs
Chrono at just under 300fps.
 Nocturnal "S", shoots less than 1 inch low (average) at 30 yds

I was given a sample of the Accunock a few years ago.  Looks pretty neat, though the technology is older than one might think.  Seems a guy gave me a sample back around '93 or '94 with the same principle though I do not know what happened to him.  Guess it could have been the same guy.  I have yet to shoot an arrow with one.  I'm intrigued enough I might give them a thorough work up this off season since the new Carbon Express nocks are horrible!  And I am just about out of my Easton Micro Lite and Old clear CE.  Was thinking I might have to go back to shooting ACC's just so I could get the X-Nock.  Was that or make my own X-Unibushing for the Carbon Express shafts.

1" difference at 30 yards changing nocks and adding the extra weight.  That's not bad at all in my book   Do you know what you ended up in FOC?

Will measure out foc tomorrow.  Don't mean to get off subject, but the accunocks did get me another 2 to 3 fps over the carbon x nocks.  They are however, fragile. A few dozen shots and one part or another breaks.  Not sure they are worth it.  As mentioned the carbon x nocks leave some to be desired.

Measured to tip if broad head
Accunocks Gave me 8.9 FOC
Nocturnals gave 7.8  FOC
1.1  difference
My understanding is that 7 FOC is pretty minimal.
Kinda surprised they were as close as they were.

[Smossy]

29.5 " Carbon x maxima hunter 350, with accunocks, 100 gr Striker broad heads.   Draw weight at 62 lbs
Chrono at just under 300fps.
 Nocturnal "S", shoots less than 1 inch low (average) at 30 yds

I was given a sample of the Accunock a few years ago.  Looks pretty neat, though the technology is older than one might think.  Seems a guy gave me a sample back around '93 or '94 with the same principle though I do not know what happened to him.  Guess it could have been the same guy.  I have yet to shoot an arrow with one.  I'm intrigued enough I might give them a thorough work up this off season since the new Carbon Express nocks are horrible!  And I am just about out of my Easton Micro Lite and Old clear CE.  Was thinking I might have to go back to shooting ACC's just so I could get the X-Nock.  Was that or make my own X-Unibushing for the Carbon Express shafts.

1" difference at 30 yards changing nocks and adding the extra weight.  That's not bad at all in my book   Do you know what you ended up in FOC?

Will measure out foc tomorrow.  Don't mean to get off subject, but the accunocks did get me another 2 to 3 fps over the carbon x nocks.  They are however, fragile. A few dozen shots and one part or another breaks.  Not sure they are worth it.  As mentioned the carbon x nocks leave some to be desired.

Measured to tip if broad head
Accunocks Gave me 8.9 FOC
Nocturnals gave 7.8  FOC
1.1  difference
My understanding is that 7 FOC is pretty minimal.
Kinda surprised they were as close as they were.

My FOC with nocturnals puts me in the 10% range.

[sakoshooter]

http://archerycalculator.com/arrow-front-of-center-foc-calculator/

A link that might help.

[AKBowman]

Rad, I'm just over 12% FOC with my Axis 300's and 125gr broadheads now. Putting on a Nockturnal would certainly change that but I really don't want to go to a 150gr broadhead. My total arrow weight now is 480grs and penetration is excellent. Accuracy is super based on our discussions earlier this year when I was trying to make 340's work. Speed is 270fps according to my Pro Chrono. Helical Blazers. Giving up some speed but accuracy and forgiveness is way more important to me.

Why not just add a slightly heavier insert and keep the broad head at 125gr?

[sakoshooter]

Rad, I'm just over 12% FOC with my Axis 300's and 125gr broadheads now. Putting on a Nockturnal would certainly change that but I really don't want to go to a 150gr broadhead. My total arrow weight now is 480grs and penetration is excellent. Accuracy is super based on our discussions earlier this year when I was trying to make 340's work. Speed is 270fps according to my Pro Chrono. Helical Blazers. Giving up some speed but accuracy and forgiveness is way more important to me.

Why not just add a slightly heavier insert and keep the broad head at 125gr?

This would work but besides adding a little bit more weight in the lighted nock and adding more weight in a heavier insert, I'd be slowing my arrow down more than I'd like to.