FOC increase

[Jeremy7306]

Ok... maybe a silly question, and I read through a few pages but didn't see it.... what's FOC? I'm not new to archery, but newish to the in 's and outs of the in's and outs of arrows.

[enewman]

Ok... maybe a silly question, and I read through a few pages but didn't see it.... what's FOC? I'm not new to archery, but newish to the in 's and outs of the in's and outs of arrows.

The abbreviation FOC stands for “weight forward of center”. The acronym FOC is just what it describes. It is the percentage of arrow weight that is located in the front half of the arrow.

Go to tuffhead.com. Read all you want to know about foc. This has been written by Dr Ashby


Once you read this you will see what most of what we have been talking about is efoc

[Pushbutton2]

The abbreviation FOC stands for “weight forward of center”. The acronym FOC is just what it describes. It is the percentage of arrow weight that is located in the front half of the arrow.



Go to tuffhead.com. Read all you want to know about foc. This has been written by Dr Ashby





Once you read this you will see what most of what we have been talking about is efoc

x2 :thumbup:

[Jeremy7306]

The abbreviation FOC stands for “weight forward of center”. The acronym FOC is just what it describes. It is the percentage of arrow weight that is located in the front half of the arrow.

Go to tuffhead.com. Read all you want to know about foc. This has been written by Dr Ashby


Once you read this you will see what most of what we have been talking about is efoc

Cool thank ya very much! I'll check it out.

[Pushbutton2]

Ok just finish an arrow to test. If it works out will build more for hunt Friday. Arrow is 25.5 ctc. 100 gn insert and 175 gn head. Arrow weight is 522 with 25% foc

That a Zwickey head?

You heading out tonight?

[enewman]

That a Zwickey head?

You heading out tonight?

No sir leaving in the morning

Yes that is a Zwickey delta. And I want be hunting with that arrow. That arrow can't handle that much weight or I have no idea what I'm doing.

But in flight that arrow looks like a bottle rocket with half the stick gone.

[TEXAS 10PT]

Ok just finish an arrow to test. If it works out will build more for hunt Friday. Arrow is 25.5 ctc. 100 gn insert and 175 gn head. Arrow weight is 522 with 25% foc

Just scored a brand new box of three German Kinetic 185gr DS 1 7/8" cut. They are our there but like finding a needle in a haystack. So excited.

[enewman]

Just scored a brand new box of three German Kinetic 185gr DS 1 7/8" cut. They are our there but like finding a needle in a haystack. So excited.

Nice. One of these day I'll get some. But I'll prolly just hang on the wall.

[Doc Peter]

You have two choices. Build a heavy slower arrow with the FOC you are looking for, or stay with a lower FOC on the arrow at the weight and speed you want...

Wish I would have started reading this thread, but now with 502 responses the info is way too much for my feeble brain to keep up with and comprehend. I understand the FOC talk, I thing I am about 10.6%.

I will ask a question(s) and hope no one condemns me for it. How do you build a heavier arrow or is it just ordering/using an arrow with a stiffer spine?

I have seen several utube videos of doing things like inserting nylon rope, salt, sand, plastic tube, weed eater line. But putting something inside the shaft, while making it heavier, wouldn't that change more than weight? What about the shifting of salt and sand?

People here are much wiser than me.

[enewman]

A heavy arrow has nothing todo with spine. If a 400 spine is all you need them you look for an arrow with an higher gn per inch. Some people do add things inside arrows. Weight tubes is a good way but it will change the dynamic spine of that arrow. If your looking at building an heavier arrow. It's better to find an arrow with the correct spine and make the weight up on the tip. Giving you more foc

[Doc Peter]

Pardon me again enewman, if I am using a 330 spine now I should perhaps look for a different mfg that makes a 330 spine with heavier gpi? and then go for say a 125gr as opposed to a 100gr tip to boost overall weight? Is that correct? How much weight is enough? I don't want to launch a cinder block when a brick will do as good/better. I started thinking and looking at this KE vs. momentum and the momentum started making a lot of sense. Now I am rethinking, which could be dangerous. Some where there is a trade-off and I am guessing I will have to experiment.

[muddyfuzzy]

FOC increase

Pardon me again enewman, if I am using a 330 spine now I should perhaps look for a different mfg that makes a 330 spine with heavier gpi? and then go for say a 125gr as opposed to a 100gr tip to boost overall weight? Is that correct? How much weight is enough? I don't want to launch a cinder block when a brick will do as good/better. I started thinking and looking at this KE vs. momentum and the momentum started making a lot of sense. Now I am rethinking, which could be dangerous. Some where there is a trade-off and I am guessing I will have to experiment.

Shooting the lightest shaft possible while still staying within your proper spine is a great way to achieve higher FOC. I will use myself as an example. My previous arrow was a 350 deep impact that weighed 430 grains and had an FOC of close to 19%. That particular shaft has a GPI if 9.6. My new set up using the 300 x-impact weighs only ten grains more @ 440 but has an FOC of 22%+. I dropped to a stiffer arrow that had a lower GPI in regards to the shaft which allowed me to make up the weight in the tip. The deep impact used a 125 tip while the 300 X uses a 165.
T.A.P.

[Pushbutton2]

Pardon me again enewman, if I am using a 330 spine now I should perhaps look for a different mfg that makes a 330 spine with heavier gpi? and then go for say a 125gr as opposed to a 100gr tip to boost overall weight? Is that correct? How much weight is enough? I don't want to launch a cinder block when a brick will do as good/better. I started thinking and looking at this KE vs. momentum and the momentum started making a lot of sense. Now I am rethinking, which could be dangerous. Some where there is a trade-off and I am guessing I will have to experiment.

Heavier GPI only affects the gross weight if the arrow. It can negatively affect FOC.

FOC is the percentage of gross weight forward of center.

There are several ways to increase FOC. Heavier broadheads, screw in weights, heavier inserts etc...

The bigger the number the weaker the spine.
i.e a 500 spine is weaker than a 330 spine.

To determine what spine u need there are several factors.
Draw weight, arrow length, tip weight, insert used, vanes, nock used...

How much FOC you want?

GoldTip has a arrow building calculator on there website.

My Bow is a Strother Moxie. Draw weight is 68# and my draw length is 31.5"

My arrows are Gold tip XT Hunters, 340 spine and are 29 1/8" long. They are 8.9 GPI and weigh 452 grains and 14.9% FOC.
I'm shooting 100 grain tips, standard insert and 50 grain screw in weights behind the inserts.
They group fine but am wishing I had 250 or 300 spine arrows.

[Pushbutton2]

Getting good at arrow hunting ;-)
3 overall second in the last month

[Pushbutton2]

http://www.archerytalk.com/vb/showthread.php?t=2398849

Whats y'all's thoughts on these?
Pretty much exactly what I'm thinking of trying next.....