Foc

[Seacoal]

Hey guys, I've finally got a little money to my name and I'm looking at getting arrows for my bow. My question is, I don't understand the importance of FOC and how it effects the arrow. Can someone please explain this to me? I've "built" an arrow on the 3rivers calc that has a very good dynamic spine match. It's foc is 20.1% and I have no idea if this is good or bad. Any help is much appreciated
Thanks, Jake

[chackworth3]

20% is good as far as FOC goes but good arrow flight is the most important thing when it comes to accuracy. FOC helps with your arrows penetration characteristics and helps to stabilize your arrow quicker after the shot. Search dr. Ashby on the internet and he can explain it a whole lot better than I can but like I said FOC is not as important as good arrow flight but if you can get good arrow flight plus that 20% FOC that would be great!

[Seacoal]

Thanks chack. Waiting till I can go to the bank and deposit my check, but I do have a full cart from 3rivers Buying shafts to fletch at home, saving myself $50

[jerp]

When I went to 20% FOC I could really tell a difference in how they really thump whatever they hit and I seem to get better penetration on hogs. The only downside that I can see is on long shots. With my set up they drop pretty quickly at 25 yards and beyond. That is no biggie for me because the only shots I ever take at that distance is at a target face or foam critters.

[Seacoal]

When I went to 20% FOC I could really tell a difference in how they really thump whatever they hit and I seem to get better penetration on hogs. The only downside that I can see is on long shots. With my set up they drop pretty quickly at 25 yards and beyond. That is no biggie for me because the only shots I ever take at that distance is at a target face or foam critters.

Thats good to know. I was hoping to increase penetration and also to allow for using a heavier shaft. Wanted to have at least 200 grains in the front, and thats where I've gotten to

[Bisch]

I have 250gr up front on my arrows. About 22% FOC. Like jerp, I have noticed better penetration with the higher FOC. Like was also said above, being properly tuned is more important than what % FOC you have. But, if you are tuned well and have high FOC, that is a win-win situation.

Bisch

[SwampRabbit]

Bringing back up this thread.

When you have a high FOC, did you guys also have to mess with your nocking point? I am tuning some arrows to a higher draw weight and when I bare shaft tuned, was looking more at spine. Now that I've got the spine down, I noticed I am hitting "nock high."

[Tracker0721]

That's the arc to your target like firing artillery. Hahaha just kidding, I didn't notice that when I went up but I only went from 125 to 175. Now I'm gonna try some stone points at 80!

[J McCoy]

100 too 150gr point weight is barely noticeable difference on POI now jumping from 125 to 200gr is pretty noticeable. Also a drastic increase in FOC. However, if you add too much front point weight this will change your dynamic spine and might require a stiffer arrow and a bow re-tune.

[SwampRabbit]

I just swapped from 40# limbs to 50# limbs. I did the online calculations to determine a good arrow setup that gave me 10gpp or higher. I ended up cutting down some Heritage 150s (500 spine) down to 28" and with a 175gr head to get them to fly straight using bare shaft. FOC for this setup is around 18%. Previously, with the 40# limbs, FOC was around 9-10% with tuned arrows (also 7 gpp.)

I noticed while bare shaft tuning for spine, that my arrow started hitting nock high (yes even at 5-7 yards.) I was wondering if that could be due to the increase in FOC. I suppose it could be due to the limb swap... but I wouldn't have expected that.