Hey dudes, I'm going to give EFOC a try. I am shooting pretty common specs so I figured I'd post up and see if any of you have a setup like mine that I could glean some information off of.
I have a 51# @ 28" (java man helms deep)
30"ish arrow
Hoping to run lightweight shafts like the GT velocity hunters and front load it as much as possible until I reach around 500-550 gr.
From what I can tell the shaft/feathers should be right about 200 gr which leaves about 300-350 up front. But I have no idea what FOC number what ends up as. It seems like you should be able to work that equation backwards to figure that out. But I haven't really looked into that yet.
Do any of you guys run a similar setup?
For comparison, I currently run 30" CX Heritage with about 160 total tip weight at about 550 gr total.
Try the calculator feature on Goldtip's website. It has a setting for foc.
I shoot GT Velocity 400 shafts with 250 grains of tip weight (125 gr Magnus stingers and GT brass inserts) out of my 50lbs/28" Morrison ILF. Total arrow weight is 500 grains and if I remember correctly that put me right around 25-30 FOC. This setup has been shooting very well for me.
I can't help you with my setup, I shoot wood, but if you want to get a rough estimate of your Balance point, here is a website that will help you make that calculation.
http://www.wikihow.com/Calculate-Center-of-Gravity
Once you know the balance point, you can plug that info along with total arrow length, into this FOC calculator.
http://archerycalculator.com/arrow-front-of-center-foc-calculator/
25-28
50#@29.5
gold tip ultra light 300 31 1/4" with 350 total up front, 26% shot from ilf very close to center shot.
Victory vforce hv 350 shaft full length, 300 up front, 27%
The victory is a lighter gpi arrow so yields more foc.
Put your arrow info into Stu's calculator. It will give you a pretty close reading on weight and FOC.
You might also take a look at Victory VForce HV. Very light shafts that works well for Efoc and UEfoc.
I'm not sure how you can figure at this point what your overall weight and point weight will be but a 30" arrow,500 grs with 300 grs up front would be about 27%.550 grs with 350 up front would be app.32%
It takes a stiff shaft to run that much up front weight and that means more overall weight.I agree on the Victory V Force HV's.My 32% ones weigh 650 grs-50-53# bows.
That's kinda why I was posting JimB. I wasn't sure if less than 550 grains was even possible to do this. Just kinda wondering how close I can get. Nothing is in stone for me, but if I can get close to 30% within that range I dont see the need to go more at this point. If not, then I suppose I'll see how much weight we need.
Thanks for the calculators guys. I actually saw the GT one before and somehow didn't realize it did that. COOL!
A lot will depend on the degree of center cut of your bow.It might be worth it to get a couple shafts and experiment.
Alright, it looks like to me with GT velocity shafts at 6.3 gpi at a total weight of 550 gr I would be at 24.77%.
To get to 30%, I would be looking at around 650 gr total.
What are your opinions on which way to go?
1. call 24% good and shoot flatter because 650 gr is overkill
or 2. 650/30% kill anything anywhere
Just curious what the general consensus is.
Depends on what trajectory you shoot the best.
I think it's always a trade off. If you sacrifice trajectory for higher weight arrow and EFOC, you'll just have to limit your shot distance. You could compensate for this by practicing all season with your hunting weight/EFOC arrow, then come hunting season long shots will be no problem. I plan on becoming competent with a 675 grain arrow (23% FOC) out of a 45lb bow out to 40 yards.
JimB: what spine works out of those recurve weights when using victory HVs?
oops! @ 28" draw, with 250-300 gr points?
oldbohunter,mine are 30" .350's with 425 grs,total up front weight,655 grs overall weight.
I haven't used their .400's but I would think that would be a good starting point for 250-300 grs up front.
snowplow,I just don't see how you expect a .500 spine arrow to shoot that kind of point weight out of a 51# bow.When you add front end weight to drastically increase FOC,you have to jump up one or two spine groups to get them to shoot.I need .350-.340 spined shafts to get in to the higher FOC numbers.You can't just pick a weaker spined shaft because it's lighter,then pile on point weight.That is the challenge with increasing FOC-keeping overall weight where you want it.
I don't think you will get .500 spine shafts to tune with 300+ grs up front.You will at least need .400 shafts.If you want to talk about 30% FOC,you are going to need .350-.340 spine.That's why people told you about the Victories.The GT's are too heavy to get what you want.
I see the problem JimB. I didn't know what you meant at first. I am not planning on running that Heritage 90 with .500 spine. As a matter of fact, I dont know why I included that information. It was just to say what I am currently running. I have never ran a EFOC arrow before.
I plan on getting Gold Tip Velocity shafts but I dont really know how to predict what spine I'll need.
It looks like from your prev post maybe .350-.400 spine.
whoops double post
I built an arrow for my son's 53# bow. It is a 29" GT Ultralight 500 with 395ish up front including a 2" footing, 225 Tuffhead, 125 gr. adapter and aluminum insert.
Total weight is 600 grains and 32.8% FOC
I wouldn't worry about the EFOC unless you are planning on hunting cape buffalo. Just pick a good quality broadhead that you want to shoot and build your arrow around that. I like a faster arrow but shoot a 200gr head because I can use a steel insert on a grizzly or get a one piece Abowyer and know the head will not break like an alluminum ferrule will and most of my arrows are in the 500+ range. I get pass throughs on everything I shoot and I don't even know what my FOC is. But I have a fast enough arrow to take game out to 40-50yds.
I forgot to add, if you are going to use a supper
Light arrow that they are not very durable. I really like the easton axis arrows with the small diameter and thick walls it helps with penetration and I don't think I have ever had one break from hitting an animal.
QuoteOriginally posted by snowplow:
I see the problem JimB. I didn't know what you meant at first. I am not planning on running that Heritage 90 with .500 spine. As a matter of fact, I dont know why I included that information. It was just to say what I am currently running. I have never ran a EFOC arrow before.
I plan on getting Gold Tip Velocity shafts but I dont really know how to predict what spine I'll need.
It looks like from your prev post maybe .350-.400 spine.
My point was,you were referencing the GT .500's when you talked about 6.3 GPI.If you use GT .400's or .350's,overall weight is going to be quite a bit more than what you wanted.
Tuning should be the first priority and your shaft choice,bow etc are going to determine the finished overall weight if you truly tune.
If you want to stay in that 500+ weight range,I would get a couple Victory V Force HV's and experiment with length and point weight first.
I see what you mean now JimB. Tuning is where I'll start but I am waiting on materials still. If any of you are curious, I have a spreadsheet full of number comparisons made and it looks like with a 500 spine GT Velocity I could get a max of 26% FOC @ 30" with 300 gr up front and only 508 gr total.
If I have to move up to a .400 spine, I could achieve a max of 23% FOC @ 30"with 275 up front
and 530 gr total.
The GT velocity shafts are a good amount lighter than the victory v force btw.
Snowplow
The Victory V Force "HV" .400 are 6.4 grains per inch.
The GT Velocity .400 are 7.4 grains per inch. At least that's what my charts say. I know the Victory's are but the key here is the HV which stand for "high velocity".
I know JimB has done allot of testing with the extreme high FOC.
Abe
This V force chart shows 7.2/8.0??
Vforce HV (http://www.victoryarchery.com/vforce_hv)
GT Velocity Hunters show 6.3/7.4
GT Velocity (http://www.goldtip.com/productdetail.aspx?ptid=191)
Please correct me if I am wrong. (especially if there is a lighter shaft to consider :) )
Snowplow
We agree with the GT chart.
On the Victory V Force HV V3 is where I have a different chart. I got mine from Lancaster Archery Supply . I have some of these arrows and the .400 are 6.4 grains per inch. The .350 are 6.8 grains per inch. Not sure if it's on there web site but the catalog has them.
They don't seem to come in the .500 spine.
Abe
snowplow,their site is erroneously giving the specs for V Force whether you click on V Force or V Force HV.It's just a glitch.
HV 350's are 6.7 GPI.HV 400's are 6.2 GPI
Again,you are calculating point weight arbitrarily,just to come up with a preset overall arrow weight.It doesn't work that way.
You can't have less point weight on a stiffer,.400 arrow and more point weight on a weaker.500 spine.
When things tune out,if you do tune,the stiffer shaft will have more FOC because it REQUIRES more point weight to tune.You can't predetermine the overall arrow weight.Tuning will determine that.A .500 spine,30" arrow is not going to fly well with 300 grs up front unless the sight window is cut quite a bit from center.On my bows,a 30 1/4" GT Velocity tunes with a 145 gr point-20% FOC.At 29 1/2",they tune with 175 gr point-23% FOC.
I personally would forget about overall arrow weight and see where the tuning takes you,then you can change shaft choices if you don't like the weight and to be honest,you aren't going to see any real difference in 50 or even more grains of overall arrow weight.
Here is the chart from victory archery.
http://www.victoryarchery.com/shaft_selection.html
Check out the first 3 sizes in red.
Vforce HV
Abe