Help with spine choice

[Austin_Hall]

I've been playing around with different arrows since getting my v3 27 in July. I've mainly shot 300 spine (axis 4mm, x imact, and easton t64s), and had decent results. Is it possible I'm overspined? I was messing around on an arrow software site and it seems to think so. Could going to a lighter spine help in any way or should I stick to 300s? Does being over spine cause any issues? I'm shooting 68 pounds at 27" draw, arrows cut to 27" if that helps any.

 

[nphunter]

Your plenty stiff but it won't cause you any issues. I'd stick with what you have unless you just want new arrows.

I'm currently shooting 300's at 26.5" and a 28" draw, I have 225gr upfront on that arrow, they fly to the same POI as my 250's in the same arrow with 200gr upfront, both weigh identical weights. I've shot all the way down to 400's and have had zero accuracy issues.

 

[BBob]

No way to really know without your total up front weight. What broadhead, insert, outsert, collar, etc...???

 

[Austin_Hall]

Running the standard outserts on all the arrows. Current set up is 27" 300 spine X impact, 40 grain outsert, 100 grain field point, 4 aae hybrid 2.0 for fletching. Haven't decided on a broadhead yet. Last season I shot swacker 2.25s and iron will wide, both 100 grain.

 

[nphunter]

You are over spined according to the calculators but it really doesn't matter in real life with a compound bow. If you are think it is affecting you go on ethics website and buy a field tip test kit or two, they have field tips from 80-300grs. This is what people do when tuning arrows with traditional bows and you can find the correct spine doing this.

I personally don't think you will learn much doing this with a compound other than your bow will be quieter and more forgiving the heavier you go, that will be because of TAW and not related to the spine of the arrow though. Typically weaker spine arrows tend to fly better at longer distances because they are easier to correct with a fletching, stiffer arrows are more accurate up close because they have the same reaction off of the bow and there is very little correction before hitting a 20 yard target. Most Field Archers tend to lean toward the weak side and most indoor archers toward the stiff side.

IMO you couldn't put enough weight on the front of that 300 spine at you specs to make it too weak, even if you shot a 300gr point you would still be in the green. I'm currently shooting an RX4 at just over 28" and 73lbs, my arrow is 26.25" long and I have 6 PM2.0 Fletchings on the back, 100gr IW inserts, 25gr IW collars and 100gr heads. So 225 upfront on a 300 spine arrow from a 73lb bow. I have 250's built to the exact TAW as my 300's, same arrow, very similar components, and can only tell a difference in POI out past 60 because the 250's are 25gr lighter out to 60 they group the same.

I don't think being overspined will cause you any noticeable issues but I do think having everything in the middle is better, companies build arrow spine charts for a reason. If there was no benefit to having the correct spine then all that would be available would be 200 spine arrows.

 

[Mighty Mouse]

qSpine says your current setup is overspined by .041". That doesn't mean it can't work for you, but it will be less forgiving of imperfections in your form/shot execution than an "optimally" spined or slightly weak arrow.

Another thing to consider is that an AAE Hybrid 2.0 is a very small vane. Even in 4-fletch, they might have trouble steering a fixed blade broadhead, especially at the speeds you'll be getting with a sub-400 gr arrow.

Bow inputs: 342 fps IBO, 27" DL, 68# DW, 6" BH, 27" ATA, 80% LO
Arrow inputs: 27" C2C, 100 gr head, 40 gr insert, 4 vanes at 3.9 gr/ea, 8 gr nock
qSpine output:

 

[bigW]

qSpine says your current setup is overspined by .041". That doesn't mean it can't work for you, but it will be less forgiving of imperfections in your form/shot execution than an "optimally" spined or slightly weak arrow.

Another thing to consider is that an AAE Hybrid 2.0 is a very small vane. Even in 4-fletch, they might have trouble steering a fixed blade broadhead, especially at the speeds you'll be getting with a sub-400 gr arrow.

Bow inputs: 342 fps IBO, 27" DL, 68# DW, 6" BH, 27" ATA, 80% LO
Arrow inputs: 27" C2C, 100 gr head, 40 gr insert, 4 vanes at 3.9 gr/ea, 8 gr nock
qSpine output:
View attachment 378281

the impact of a smaller vane on the flight of arrows with BH is sometimes overestimated - to be taken into account too: a BH usually adds a lot of weight to the front thus increasing FOC thus moving the centre of gravity towards the front.....and what this means is that the leverage for the drag caused by the vanes actually becomes bigger ....so longer lever and small vanes can have the same steering impact as smaller lever and big vane surface.

wrt Pinwheel app: IMO the best "tool" on the market, comes not for free, but the few $$ spend on the app are definitely justified by avoiding all the costly mistakes when building arrows.

 

[Mighty Mouse]

the impact of a smaller vane on the flight of arrows with BH is sometimes overestimated - to be taken into account too: a BH usually adds a lot of weight to the front thus increasing FOC thus moving the centre of gravity towards the front.....and what this means is that the leverage for the drag caused by the vanes actually becomes bigger ....so longer lever and small vanes can have the same steering impact as smaller lever and big vane surface.

Fair points. I'd still personally be concerned about the ability of four 1.95"×.33" vanes to effectively steer an Iron Will wide at 300 fps.

 

[5MilesBack]

a BH usually adds a lot of weight to the front thus increasing FOC

Why would the BH add anymore weight than an equally weighted field point? The FOC should be the same for both.

 

[bigW]

Fair points. I'd still personally be concerned about the ability of four 1.95"×.33" vanes to effectively steer an Iron Will wide at 300 fps.

I'm with you here, an Iron Will type BH definitely will amplify the error margin IF the arrow-bow system is not properly tuned.

 

[bigW]

Why would the BH add anymore weight than an equally weighted field point? The FOC should be the same for both.

usually you don't hunt with FP, but use them for target and 3D, and especially in unmarked 3D most shooters prefer a flatter trajectory and shoot a relative small FOC and a lighter arrow, hence lighter FPs.

 

[nphunter]

usually you don't hunt with FP, but use them for target and 3D, and especially in unmarked 3D most shooters prefer a flatter trajectory and shoot a relative small FOC and a lighter arrow, hence lighter FPs.

A broadhead vs field point makes no difference on FOC. If they are the same weight the FOC should be the same or very close to the same, anyone who practices with light field tips and then switches to heavy broadheads without totally resighting is a fool. The 3D statement isn't true, ASA limits the speed of an arrow to 290fps, which is the limit for all shooters, if you have a 29" draw shooting a modern bow you will be shooting heavy arrows with heavy field tips to meet that requirement.

Iron Wills fly OK but those four 2.0's are going to struggle to steer them with any execution or form errors. I've shot 2.0's with IW100's and they are finicky but fly great with 3 Max Stealths. Personally, I would want more vane for steering fixed heads. I like low-profile vanes and actually shoot six 2.0's, I have shot IW's but pretty much shoot mechanicals now.

 

[Austin_Hall]

They sure are small. I wanted to try them, but I'm switching back to TAC Driver 2.75s. They are really loud in my bow.

 

[bigW]

A broadhead vs field point makes no difference on FOC. If they are the same weight the FOC should be the same or very close to the same, anyone who practices with light field tips and then switches to heavy broadheads without totally resighting is a fool. The 3D statement isn't true, ASA limits the speed of an arrow to 290fps, which is the limit for all shooters, if you have a 29" draw shooting a modern bow you will be shooting heavy arrows with heavy field tips to meet that requirement.

Iron Wills fly OK but those four 2.0's are going to struggle to steer them with any execution or form errors. I've shot 2.0's with IW100's and they are finicky but fly great with 3 Max Stealths. Personally, I would want more vane for steering fixed heads. I like low-profile vanes and actually shoot six 2.0's, I have shot IW's but pretty much shoot mechanicals now.

1. we in down under don't have a speed limit in 3D - I shoot 350 grain arrow with an FOC of approx. 8 at 318 fps; if there would be a speed limit I would drop my poundage, shooting a lighter arrow with same FOC - flatter trajectory is just the way to go if you shoot unmarked distances, and if you have a comp with 2 arrows rounds thus shooting quite some arrows a day (not like hunting!) at the end of the comp you will feel the difference between 60# and 70#.
2. of course 1 lbs of feathers has the same weight as 1 lbs of steel - no one questions this. The point is that a lot of the RF fan boys prefer an extreme high FOC by using heavier inserts plus heavy BHs - and then they think that to steer these FOC monsters they need much more fletching - which is not always the case due to the increased leverage (= center of gravity to nock).

 

[Austin_Hall]

usually you don't hunt with FP, but use them for target and 3D, and especially in unmarked 3D most shooters prefer a flatter trajectory and shoot a relative small FOC and a lighter arrow, hence lighter FPs.

I'm not hunting with field points, FOC is a huge part to me, I shoot same weight fieldpoints as I do broadheads. I simply practice with fieldpoints because sharpening is tiresome. POI is matched when I make a broadhead change and checked once a week from one month before the season starts until rifle begins. Then it's back to the old easy on targets and wallet fieldpoints.

 

[bigW]

I'm not hunting with field points, FOC is a huge part to me, I shoot same weight fieldpoints as I do broadheads. I simply practice with fieldpoints because sharpening is tiresome. POI is matched when I make a broadhead change and checked once a week from one month before the season starts until rifle begins. Then it's back to the old easy on targets and wallet fieldpoints.

I didn't say that you are hunting with FPs - my comment was a response to @Mighty Mouse 's comment about the impact of fletching surface on steering capability, and that you don't need automatically more fletching surface when shooting BH if the leverage is long enough - fletching surface is only one part of the steering force equation, the other part is the leverage and that is often overseen.

 

[nphunter]

1. we in down under don't have a speed limit in 3D - I shoot 350 grain arrow with an FOC of approx. 8 at 318 fps; if there would be a speed limit I would drop my poundage, shooting a lighter arrow with same FOC - flatter trajectory is just the way to go if you shoot unmarked distances, and if you have a comp with 2 arrows rounds thus shooting quite some arrows a day (not like hunting!) at the end of the comp you will feel the difference between 60# and 70#.
2. of course 1 lbs of feathers has the same weight as 1 lbs of steel - no one questions this. The point is that a lot of the RF fan boys prefer an extreme high FOC by using heavier inserts plus heavy BHs - and then they think that to steer these FOC monsters they need much more fletching - which is not always the case due to the increased leverage (= center of gravity to nock).

Sorry, I didn't realize you were down under. I agree that a faster arrow is more forgiving when it comes to judging distance, there is no doubt and if I only hunted deer I'd be shooting lighter arrows with mechanical heads due to the advantage over misjudged trajectories.
I agree to some extent about FOC and smaller fletching, however, in the OP's case, the four 2.0's are not going to be enough to steer a fixed head well. I'm running 21% FOC and I needed six 2.0's to effectively steer fixed heads for me reliably, they all worked if my form and execution was spot on, but going to six over four had a notable difference in correction, three large fletchings did even better. I can shoot a FP out to 60 yards with zero fletching out of my bow and have it group with my fletched arrows, put a fixed broadhead on and it takes effort to get good groups with small fletchings.
I'm also talking about shooting 60+ yards here, for 20-30 yards anything will work, I can shoot about any combination accurately enough to kill out to about 45 yards, after that you can start to see the difference in things like cutting diameter, fletching size, weight, etc.

 

[bigW]

Sorry, I didn't realize you were down under. I agree that a faster arrow is more forgiving when it comes to judging distance, there is no doubt and if I only hunted deer I'd be shooting lighter arrows with mechanical heads due to the advantage over misjudged trajectories.
I agree to some extent about FOC and smaller fletching, however, in the OP's case, the four 2.0's are not going to be enough to steer a fixed head well. I'm running 21% FOC and I needed six 2.0's to effectively steer fixed heads for me reliably, they all worked if my form and execution was spot on, but going to six over four had a notable difference in correction, three large fletchings did even better. I can shoot a FP out to 60 yards with zero fletching out of my bow and have it group with my fletched arrows, put a fixed broadhead on and it takes effort to get good groups with small fletchings.
I'm also talking about shooting 60+ yards here, for 20-30 yards anything will work, I can shoot about any combination accurately enough to kill out to about 45 yards, after that you can start to see the difference in things like cutting diameter, fletching size, weight, etc.

a little bit off topic, but to add some food for thoughts: you often hear that the heavy front is pulling the arrow straight - that's actually not true, what's overseen is that it is actually the centre of gravity that moves on the trajectory, hence with high FOC and a light tail you always have an arrow that is tilted wrt the trajectory where the drag of the fletching fights the dropping tip (pivots around the centre of gravity). My hunting arrows have not more than 13% FOC, and I wouldn't hesitate to go even lower, and I shoot the TAC 2" driver vanes in a 3 vane configuration with a 1.5 deg offset; I shot the 2.25" TACs before, shot the 2" blazers, and there is not difference in accuracy at further yardages.

 

[nphunter]

a little bit off topic, but to add some food for thoughts: you often hear that the heavy front is pulling the arrow straight - that's actually not true, what's overseen is that it is actually the centre of gravity that moves on the trajectory, hence with high FOC and a light tail you always have an arrow that is tilted wrt the trajectory where the drag of the fletching fights the dropping tip (pivots around the centre of gravity). My hunting arrows have not more than 13% FOC, and I wouldn't hesitate to go even lower, and I shoot the TAC 2" driver vanes in a 3 vane configuration with a 1.5 deg offset; I shot the 2.25" TACs before, shot the 2" blazers, and there is not difference in accuracy at further yardages.

I'm not worried about penetration or speed, the reason I wanted higher FOC was because it should help with deflection, the more weight up front the harder to defect the direction of the arrow assuming the tip hits an object. I have not noticed any negative or positive effects from switching to a high FOC arrow other than being able to put 225gr of steel on the tip has made them more durable than my previous arrows. I have killed elk with passthrough's with arrows from 330gr all the way up to 500gr with a variety of fixed and mechanical broadheads, all of the animals have died equally dead.

I had great luck shooting arrows as low as 7% FOC with no negative effects as well and all have flown equally well for me, the biggest thing that has had effect on the flight has been fletching and head choice when talking about broadheads. For FP they all fly excellent. I'm defiantly not a bone-splitting, high FOC pushing person, I just shoot what I want and make changes according to my personal results on things I kill.

 

[Austin_Hall]

I didn't say that you are hunting with FPs - my comment was a response to @Mighty Mouse

Alright, I misunderstood. I just wanted to clarify that I shoot the same weight FPs and broadheads.