Percentage of FOC
 

Do you guys know what the percentage of FOC should be on a arrow?

RE: Percentage of FOC
 

i just got thru going over this with moose at lancaster archery. depends on the use he said.

RE: Percentage of FOC
 

What do you mean by the use? It is for hunting.

RE: Percentage of FOC
 

I am no expert by any means but 10-12% is the recommended FOC according to a book I own.

RE: Percentage of FOC
 

i was picking between 80 and 100 gr glue ons for my 3d arrows. the 80's provided a 8.5% foc. (i ordered some of each). he said that's fine for 3d, but you'd need more for field archery, and i'd imagine more for broadheads. i think i'm around 12% on my broadheads and some guys on here report fine results with 14%- even 16%. hopefully some folks who know, and didn't just ask someone - like me - will respond to what's good for each use mentioned above. i'm just offering 2nd hand knowledge really.

RE: Percentage of FOC
 

I can tell you guys that my 3D arrows out of the allegiance are flying fine at around 7% and 310+ fps. I have 65 grain screw ins, and inserts in the front of pro 22's along with REALLY heavy 4" vanetecs on the back (9 grains each) along with easton 2115 uni bushings and g nocks. This will be my setup to use this year at the local shoots if I decide to shoot pins class. I was shooting the setup out to 60 yards last week with no issues, I almost piped one at 50 yards actually and smashed the back of the bushing so bad it can't be used or pulled out of the shaft. The nock turned into little bitty pieces I think.

RE: Percentage of FOC
 

Outdoor target and 3-d, 7-9% works good. For hunting I've had real good results with 12%. For indoors ( 20 yds ) I use more 16+ %, because of the heavy points I use to soften up the huge arrows I use. 200 + grain points.

RE: Percentage of FOC
 

With the blazers and 100gr muzzy mine will be at 10.45percent
I guess that will be good enough?
28.5 inches long
shaft weight=276gr
broadhead=100gr
nock=12gr
insert=15gr
fletching=15gr
crestining=15gr=433gr

RE: Percentage of FOC
 

thanks for the great info guys.

RE: Percentage of FOC
 

Is the above FOC go good with the set up I described?

RE: Percentage of FOC
 

Assuming you've got the bow tuned up and your arrows are shooting where you aim them, yes. Definitely.

RE: Percentage of FOC
 

For shooting field points ina 3-D set up, a FOC between 8% and 9% works great for most shooters. Don't go lower than 7% though becauseanything lowercan and will cause arrow flight problems. With mostbroadheads you will want a FOC of at least10% for good flight. When using biggercut on contact (elk hunting)typebroadheads a FOC of 12% is even better yet. Most arrow companys recomend a FOC beno lower than7 or 8%and not over 15%.As already mentioned, depending upon what you are using the arrow for will determine that proper FOC. Here is a bit of info about FOC taken from hunters friend. I am posting the link as well because they have a lot of usefull info that could help archers out.

http://www.huntersfriend.com/arrowhelp/arrow-selection-4.htm




Front of Center Balance:

If you've ever played a friendly game of darts, you've surely noticed that the dart is designed so that it's heavy in the front, and light in the back. If the dart were weighted the opposite way, with the tail being heavier than the tip, it would literally spin around and hit the target tail-first. Obviously the ballistics of a dart and an arrow are a bit different, but the underlying concept is similar. A projectile's flight is most stable when most of the projectile's mass is positioned Front of Center (FOC). As such, an arrow should be heavier in the front than in the back. But how much? Where's the "perfect" balance point?

This is another hotly debated issue among archery enthusiasts. Some claim that FOC makes little or no difference, others swear that FOC has a profound effect on accuracy. Even the industry experts don't seem to agree, as the ballistic physics for FOC include some rather elastic variables that make finding an "mathematically optimal" FOC very difficult to declare and prove. To make matters worse, we even see a variation in how FOC itself is calculated, depending upon which "expert" you ask. So while we have no interest in the fine points of the debate, we will agree that the tricky issue of FOC is at least worth considering when purchasing a new set of arrows.

With all that said, it is generally believed that an arrow with a high FOC will fly well, but with premature loss of trajectory (nose-diving). While an arrow with a low FOC will hold it's trajectory better, but it will fly erratically. So again, another trade-off for you to consider.

While there doesn't seem to be a magic number to aim for, it is generally agreed that the optimal FOC balance for an arrow is somewhere between 7% and 15%. In the example on the left, the 30" long arrow has balance point that is 3" forward of the arrow's actual center (15"). So it's FOC is 3/30 or 10% - a reasonable FOC balance.

So when you order your custom arrows, keep FOC in mind. If you choose heavy 5" vanes and an anorexic 50 grain tip, you'll likely have an FOC that is too low. On the other hand, if you choose 3" lightweight feathers and a jumbo 175 grain tip, you'll likely have too much FOC. Choose an arrow setup that will give you an FOC balance of roughly 7-15%.

FOC Calculators:

To find the approximate FOC balance of your finished arrow, simply balance your arrow on some kind of fulcrum such that the arrow sits on it's own without tipping forward or backward. Mark this position on the arrow where it balances perfectly. Then measure the entire arrow (from the crotch of the nock to the end of the point), divide the arrow length by 2, and make a mark that indicates the exact center of the arrow. Now just measure the distance between your marks. If you divide the distance between the marks by the total arrow length, then multiply the result by 100, you'll have a reasonable estimate of your arrow's FOC percentage.

There are also a number of FOC calculators available online. Here is a sample of one FOC calculator, a simple program to help you predict the FOC balance of your custom arrows. This particular calculator uses 2003 Gold Tip specifications, but the concept is the same regardless of which brand of arrow you ultimately choose. We suggest you take a little time to experiment with the calculator, and learn how each variable affects FOC balance.

RE: Percentage of FOC
 

I think speed has an impact on accuracy with FOC also. Last week I was shooting my .300 spine 100 grain tip arrows at around 260-265 fps with a 6.5% FOC. I ended up getting 3 inch groups at 60 yards with my hunting arrows (70# bow backed down half way). Went back out with 70# bow maxed out after getting correct pivots installed and my bow was now shooting these same arrows at 285 fps with 6.5% FOC. After two hours of getting frustrating 5-6 inch groups at 60 yards, I finally woke up and decided to throw on my 125 grain tips to see what would happen. Immediately I got my 3 inch groups back at 60 yards with a new arrow weight of 468 grains at 278 fps with a FOC of 8.5%. Proves a couple of things to me…my bow likes a slightly softer spine arrow (which was gained by removing my 100 grain tips and installing the 125 grain tips), and/or my arrows needed a little more FOC at speeds over 265 fps. Note: The above groups were with field tips and mechanicals.

RE: Percentage of FOC
 

When you say groups are you talking three arrows?

RE: Percentage of FOC
 

You can use 3 arrow groups if you like, but I have a habit of using 5 arrow shot groups from my rifle reloading days. I could never put all 12 in a 3 inch group at 60 yards. Keep in mind for this kind of testing I'm using the hand picked 6 from the dozen (if there is such a thing with these arrows). Some of the groups are a little less than 3 inches and some arejust over3 incheswhen measured from center shaft to center shaft. I just call it anaverage 3 inch group for the day.

Did you get your bow dialed in yet? How do you like it?

RE: Percentage of FOC
 

I have never had a more accurate bow in my life!Very Very Forgiving!
Quiet and accurate.Not a speed demon but 264 is plenty.
Have not shot over 40 yrd at my house dont have enogh room.