Do weighted inserts change the spine of the arrow?
Yes they do, if you need more weight up front ,I like too use a heavy adapter for the B.H.
Adding weight up front weakens the spine.
Weighted inserts don't actually change the spine of the arrow, but extra tip weight will weaken the spine and make the arrow shoot like it has a lower spine. That is because a heavier tip increases the inertial resistance of the front of the arrow, so the shaft will bend more as it tries to force the front of the arrow to start moving. Some people refer to this as the point "pushing back" on the arrow as it resists the force of the limbs acting on the string to move the point forward. The word "inertia" comes from the Latin word "iners" which means lazy. An object with mass is said to be lazy and doesn't want to change its velocity or direction unless a force is exerted on it. The higher the mass, the greater the force that is needed. Thus, a greater force must be exerted by the limbs, through the string, then through the arrow shaft, in order to make a point of heavier mass begin to accelerate forward. When that happens, the force being exerted longitudinally through the arrow shaft will cause it to bend more laterally and thus make the arrow behave as if it had less bending resistance (i.e., a lesser spine). Actually the spine stays the same but more bending takes place because a higher peak force is being exerted on the shaft.
Allan
Ive got to where I just avoid the brass inserts, that go up in the shafts, when bare shaft tuning. I use a heavier head and an adapter to add wt to the front. Last time I tried tuning with the inserts, i was ready to pull my hair out before I was done....I use the Bemans and the inserts (100gn)are inset approx 2-3 inches, I know they effect the spine..just dont know HOW they affect the spine..??
I just got finished with my last hair. I have pulled them all out. I've been shooting several hours today trying to get me bow, 70lbs @ 30.75 in., to shoot a 31" CX 350 with 100 grain inserts and 250 grain head. NO STINKING LUCK.
I have moved silencers down, built out the side plate. NO LUCK.
After moving nock point up and down I can't even get the porpoising to stop. UNBELIEVABLE.
I am missing something OR I am barking up the wrong tree because it is not supposed to work.
What stiff, narrow, carbon arrow WILL work with my bow and 300 + grain heads?
Anyone? Anyone?
Richie,
I can tell you that I have been shooting AD Hammerhead Trads with either 100 grain brass inserts and no screw-in weights on the back of the inserts or 100 grain brass inserts with 70 grains of screw-in brass weights on the back of the inserts. I also am using aluminum collars over the end of the shafts between the shaft and the brass insert, and I am using uni-bushings and g-nocks along with 4" four fletch at the tail end. I have 300 grain heads on the arrows. My draw length is a little shorter than yours at 29 1/2", and my arrows are 31 3/8" from the throat of the nock to the front of the brass insert. The bow I shoot them out of is a 60" Super Shrew 68#@29 1/2". I get great arrow flight. The Hammerheads may not be "narrow" by your definition, but they sure work well for me. I also shoot a lot of Carbon Express arrows. They are really nice but are more sensitive to bow variations than arrows made up using the AD shafts.
If you go over to the Dark Continent forum you will see some more information about heavy arrows from heavy bows. Also, you might give Paul Mattson at Badger Arrows a call. He has a lot of experience with arrow selection. Hope this helps.
Allan
Richie, my guess is your soft in spine, decrease point weight or add another set of silencers to the string or lower brace height. You may try the grizzlystick safari's, seriously stiff arrow.
I have found that a 300gr point with aluminum insert vs a 200gr point and 100gr brass insert do not have the same dynamic spine on the same arrow, putting some of the weight in the shaft stiffens the dynamic spine for me. Has anybody else seen this?
Thanks guys....Allan, I really like the narrow diameter of the carbons. I normally shoot the fat 2317's and they shoot very well. I just wanted to try a stiff narrow carbon. I thought the CX 350' would do the trick.
Katman....I haven't added silencers but I have moved them toward the middle. No significant change. However I haven't lowered the brace height. Actually I raised it back to 9 inches (it gradually lowered to 8.75) where I normally keep it where it is the quietest. Maybe I need to lower it a bit. The CX's currently have the 100 grain inserts. Based on what you have said the arrow would be even weaker if I used the aluminum insert instead.
I have ruled out the Grizzlystiks because of price and large diameter like my 2317's.
I don't know if it is possible but ideally I would like a super stiff and light arrow where I could add a pile of weight to the front, which is where I want it.
Your input is really appreciated guys...I hope I can reciprocate.
I havent used the brass inserts, but I questioned using them on a recent tuning post to get my point weight up because my shaft was overspined . He is how it was explained to me.
The extra legnth inside the shaft (lenght of the longer brass inserts) in now rigid. We know for sure that the part of shaft where the longer insert make contact with the shaft at will NOT bend, effectively makeing the flexible part of shaft shorter. ie: a shorter shaft a stiffer spine.
NOW, take that same weight and put it out front of the shaft with a shorter insert, giving more part of the shaft flexiblity, will give a weaker spine. Plus, the extra wight is out front now , whick make the shaft act even weaker.
To me a brass inseret is a catch 22.
More weight up front=weaker spine
Less part of the shaft being flexible=stiffer spine
Atleast that how me and the voices inside my head have in fiqured out. I choose to stay away from them. Not say they wouldnt work for you or anyone else. :banghead:
So...if I could find something about six inches long that would fit tight inside the front of the shaft then it would be alot stiffer.
Any ideas?
Anything I can think of that would fit and be stiff will also be heavy.....meaning you still have to give up your heavy heads.
Here are some ways I know of to effectively stiffen the spine. They all have trade-offs.
Add a fourth fletch (and go with longer ones)
Use a dacron string instead of FF
Use a heavier nock (or try to add "some" weight to the back of the arrow
Add weight to the string (more silencers)
Basically, anything to lessen the "thump" your arrow is getting up the rear by your bowstring.
How much foc are you looking for?, I would think that with that length arrow 100 gr brass insert and 200gr heads you would be over 20% and into Dr Ashby's efoc as long as you do not have cap wraps and huge feathers. An extra set of silencers would rob energy from the arrow, might be worth a try tying on a second set of rubber whiskers and see if you can get the cx to tune, you have plenty of horespower in the 70# and 30.75 draw.
The grizzlysticks are very costly and have a large front end but are tapered and recover quickly which helps penetration. I have broken every shaft I have owned hitting something else besides the intended target except the safaris. The AD are also a very nice tapered shaft, I use them for 3D. The tapered shaft shoots better over a wider spine range and you may need that for your heavy poundage. Good luck on your search.
"Anything I can think of that would fit and be stiff will also be heavy.....meaning you still have to give up your heavy heads."
If a long internal footing makes the arrow stiffer...the weight of the same footing will not weaken the spine like the heavy heads do..does it?
"How much foc are you looking for?, I would think that with that length arrow 100 gr brass insert and 200gr heads you would be over 20%"
Yes it is about 21% with that setup. I could live with that if it didn't kick left.
It sure is nice to discuss this with lads that know more than me.
Thanks
Richie, you're correct, it's adding weight but not weakening the arrow. The way I think about it is to think of it as supporting it's own weight.
Since you're asking about 300+ grain head I figured you're on the path to high FOC...and adding weight (by using internal footings) anywhere but the tip is kinda counterproductive. That's why I mentioned the weight.
Soilarch,
"not weakening" or actually stiffening the arrow?
If a 6" internal footing will stiffen the arrow then that may be all I need. Then I could add good weight to the front to get whatever FOC it will allow. I have no idea if it will work but if it has worked for others I will try it.
I do plan on using 5 inch nanner turkey feathers but I don't want to do too much, if anything, to slow the arrow in order to stiffen it.
Thanks again.
It sure feels good to solve all the worlds problems with such an inadequate thinker.
Can't answer that. Not done it myself. I read waaaaaay too much on here and other places.
Seems like it depends on too many variables. It stiffens PART of the arrow...and effectively shortens the part of the arrow that does flex. It's kinda like adding weight and shortening your arrow. Taking an inch off the length of an arrow is a routine way of stiffening the whole shaft. BUT remember your adding weight that the part of the shaft that does flex will have to support.
Confused yet? Sorry I'm not a very good communicator.
The answer I guess is that you have to try it, play with different lengths of footing and see if things improve.
Good info.
thanks
Garlin, basically adding 25 gr. up at the head, insert or adapter, will change the spine on Aluminum arrows approximately 3-5 lbs. Example: if you go from 125 gr head to 150 gr. the shaft spine is 3-5 lbs lower. Sometimes you can compensate by lowering or raising the string 5-10 twists. If your arrow weight is around 9x the effective weight of the bow, your arrow weight is good. Example: 9 x 65# = 585 grain arrow.
Richie, you mention a the brace height of 8.75" +/- is that what the factory recommends? My set for a 66# @28" Bear Custom TD is 7 3/8" which is lower than the factory and what most people use. But it works fine for my 29" XX75 2219's. Try a lower string with the stiffer shaft.
If the arrow kicks left of where your 2317 shoot, they are stiffer, weak would go to the right. If they shoot left, we can lower the string, or add weight. But, you already have 300 gr. at the head. That suggest the shaft may be too stiff period. Just the opposite if they are right. Make sure the nocks are not tight and lower the string.
Best flight from an arrow comes around 27". Arrows that are longer, or shorter may not shoot as well and certainly, won't be as stable in the wind. Increasing the forward weight changes the flight characteristics as well. Putting too much weight out front will result in a loss of trajectory. Imagine what would happen if you were shooting an arrow of 700 Grains. You might get great penetration, but your range would be limited to 30 yds. It has been my experience that if the balance point is more than 3" ahead of the mid-point (tip to nock), the arrow will drop faster than if it is more balanced.
Whoaaa Nelly.....
"If your arrow weight is around 9x the effective weight of the bow, your arrow weight is good. Example: 9 x 65# = 585 grain arrow."
Not if I want heavy more powerful projectiles.
"Richie, you mention a the brace height of 8.75" +/- is that what the factory recommends?"
Yes..that is what Black Widow recommends and it seems to be the quietest at that point. However I am not opposed to changing it if it helps stiffen arrow spine.
"If the arrow kicks left of where your 2317 shoot, they are stiffer, weak would go to the right. If they shoot left, we can lower the string, or add weight. But, you already have 300 gr. at the head. That suggest the shaft may be too stiff period. Just the opposite if they are right."
I think you may have that backwards. I wish it would kick right, then all you kind and generous guys would not have to put up with all my ignorant questions. My 2317's kicked right until the 300 grains I put up front weakened it juuuussssttt right. But they are still fatter than I would rather have.
"Imagine what would happen if you were shooting an arrow of 700 Grains. You might get great penetration, but your range would be limited to 30 yds."
Yea..I don't want to shoot 700 grains...its too light. I shoot 750 to 950 grains from 30 yards with no problem whatsoever, as do many others. To me, the drop or loss of trajectory has nothing at all to do with accuracy.
I personally don't know many people who shoot animals much more than 30 yards with any arrow.
If my arrow shoots perfectly flat from 25 yards
away then my arrow is too light for my bow and I am waisting the lethal characteristics of the weapon in hand.
Richie, I think I understand what you want, but you are going where few have gone, "The Road Less Traveled". The manufacturers don't know you yet, and they don't see a demand. Have you contact any carbon guys to see what they have to offer?
If you get a chance look at the latest issue (fall) of TradArcher's World, the article by David Soza "Tuning the Carbon Arrow". Although he is working primarily with lighter weights, he may give you some ideas.
Richie, there is an article in Primitive Archer, Feb/Mar. 2009 by Robert Hurst on The Bare Shaft Method. This article and the above mentioned, both discuss weak vs stiff and their grouping.
"Putting too much weight out front will result in a loss of trajectory"
Putting to much weight in the entire arrow setup will result in a loss of trajectory. The arrow does not know where the weight is when it is motion. In fact if the higher foc arrow stabilizes quicker it looses less energy recovering from paradox then it may see less of a drop in trajectory all else being equal. I do not believe the old saying efoc arrows nosedive, at least mine don't.
The internal footing sounds like it is worth a try. OL had a thread about internal footings and what worked on this site, do a search. Let us know how it works.
Are you tied to those particular arrows? I am using the Axis FMJ arrows and love them. Skinny, tough and shoot great. Are you bare shaft to fletched tuning? This is the best method I have found to get my arrows tuned to the bow.
Easton makes and FMJ in a 250 spine that should tune out perferct at your draw length and mass up front. You can get half a dozen ordered at any archery shop. Just remember with the inserts that you want to cut the length off the back of the arrow as you work on tuning.
First, I apologize for getting off topic, which was the question about weighted inserts. In my experience although arrow weight is important, and too much weight may not work for everyone. It is an will remain a personal choice and everyone should do what works for them.
Yes, I agree added weight in inserts or adapters has the effect of reducing spine.
Well...I have the CX 350's now and want to make sure they will not work before I get other ones. I did just read about he FMJ's.
The arrow I have been tuning with is fletched and shows too weak.
Richie, Where does your bare haft arrow go and what hand do you shoot? I may have missed it in the thread. If I understand correctly your arrow is kicking left? Are you left handed?
Your arrow set-up in the spine calculator is like 40# dynamic spine, and your bow is like 80. Your draw length with that weight bow and standard carbons is just not an easy fit. Here is what you can do to get a base line. Get some good silencers on the bow. Nice heavy ones. Drop down to max 200 gr. on the front. Build out your side plate 1/4" or so past center. That could get you in the ball park. The brass inset will stiffen the shaft more than all point weight so I would stay with that and it may get you 225 on the end. That would get you over 16% FOC and over 600 gr. Bow tuning could get you set with that. I know that is not quite what you are after, but at your weight and draw length that is some serious killing power.
Now to go heavier you can add internal full length weight. I have not used the CE's, but if they have the same ID as other standard carbons, you could use the GT nock end inserts and weight system. That would offset the front weight and give you arrow weight and a stiffer dynamic spine. Again you will be on the lower side of the
FOC. More FOC will be a little harder. Footing is probably where you want to go. It will stiffen the shaft and provide FOC. I have read some stuff on footing, but not much that really explained its effect overall on arrow dynamic spine and FOC.
One option could be some footing or what ever you would call it when placed at the back of the arrow. That would add nock end weight to stiffen the shaft's dynamic spice and stiffen the shaft by reducing the flex of the shaft. You get double effect from that where footing the point weakens some by adding point weight and stiffens the shaft by reducing flex. I have never read anything about adding footing to the back of the arrow, but I think in theory it would work. You would lose some FOC.
I am wondering if anyone has ever tried to add footing to the center of the shaft. It would stiffen the center of the bend. It would add centered weight so not shift the FOC much. I have no idea what all that would do, but it does make me wonder. I am thinking it would substantially stiffen the arrow, but could cause some odd flexing stuff, buy crating multiple bending areas rather than one bending area.
You need some specialized help. It is the place to get it. Maybe a second post on footing shafts would help attract the right responses.
Thanks extrema,
Correct...I am shooting right handed (string hand) and the arrow is kicking left.
I just tried some aluminum external footings. NO LUCK. I cut a 7 inch piece and slid over the front of the carbon. I think the weight of the footing just keeps it weak. I was thinking maybe a stiff piece of aluminum would actually stiffen the arrow to enable the use of 350-400 grains up front.
A 200 grain field tip with the 100 gr. insert shoots fine. If I could get the insert out I feel like my 285-315 grain Grizzlies with adapters would work well with the normal inserts.
But...I am trying to get more than that and I really appreciate you guys riding this train to nowhere with me.
Not to be redundant, but I would like to get a 31 inch shaft stiff enough to put 400 grains up front pushed with 70 lbs.
I will keep searching and thanks again.
Richie, from what I am told, the CE 350's are overspined for 70# at 30". Please contact one of the arrow merchants on this site and get advice. I shoot up to 400gr up front with no problems. They shoot side by side with 2317's. I have my PTF set at 9" brace 5/8's over center for nock. I am shooting a 4 fletch with 250gr. I have shot 350-400gr out of this same set up. Maybe my eyes are bad but the arrows don't seem to care for the difference in spine. My advice is to shoot them using a release if you really want to tune them properly to the bow. After that is tuned, go back to your finger release.
Chuc,
I have strictly been using the fletched carbon you sent to get my current results. With the 100 grain insert and a 200 gr. field point it shoots good. I seem to get a left kick with anything heavier than the 300 total up front. Like I mentioned above(another post) if I used normal inserts I think the 285-315 Grizzlys I normally use would work fine but I want to do more than that. I really like the idea of the heavy inserts but I want the heavy heads as well making up a total of about 400 grains.
The fletched arrow I am using(I got from you) is 31 inches from nock groove to end of brass. I am pulling almost every bit of that.
I wonder if the one inch difference in your arrow is the critical difference in how our arrows perform. Yours working and mine not.
I normally like to fletch with nanner style turkey feathers. That may stiffen it up a bit but probably not enough to shoot 400 grains.
BTW Chuc, The gamegetters are some fine aluminum arrows. They shoot perfect. Love the inserts in them. They are very pretty arrows as well.
I'm still searching.
Thanks Chuc
Well then, put some inserts and heads on the full length and start from there bareshafting.
When I get to a vice to get the brass inserts I may can do that.
Although I am not sure how that would help. Anything longer than the 31 inches I have now and unfletched will be weaker. The 31 inch fletched arrow is as short as it can be.
BTW,
I was just shooting the Gamegetters. I chronographed them with a 300 gr. field point and 100 gr. insert making the total weight 850 grains.
They shot 173 fps. Not bad I guess.
Your not going to like what I'm going to say Richie...........but.............a 2317 is .200 deflection. I LOVE a 2317..shot them for 20 years......Now i shoot...........you guessed it GrizStic Safaris..200 deflection also. I shoot a 820 grain arrow including a 185 grain head....bare shaft out to 25 yards out of my 66# bow at 29 1/2"..........Contineous tapers are so easy to tune and recover so quickly....Your trying to tune a .350 deflection arrow with 200 grain head....it's flying like a tuning fork............You need 200 deflection..
Joey,
That is exactly what I am trying not to admit without exhausting all of my options with the CX 350's I have now.
Oh yea the 2317 are a dream arrow for my bow. I am just trying to step up a bit to another setup.
Its fun.
I love the heavy arrow like you mention with the Grizz's. My druthers would be to have the liberty to get that heavy weight up front rather than be forced to have it throughout the shaft.
yea I guess I want my cake and eat it too.
QuoteOriginally posted by Richie Nell:
BTW,
I was just shooting the Gamegetters. I chronographed them with a 300 gr. field point and 100 gr. insert making the total weight 850 grains.
They shot 173 fps. Not bad I guess.
Ya not bad. :rolleyes: :D I wish I had your problem. :D
I don't think the CE 350's are .200 deflection. The number on these particular arrows are not representative of deflections. CE 90's, 150's, 250's, and 300's.
CE heritage 350 list as .320 on the web site.
Grizzlysticks being larger in the front have some built in foc, the fmj may work since it spines at .250
I have a pretty good source for Griz Stics :D . I'll keep my eyes open if any Safaris seconds pop up again....