question about FOC
 

Hi, just wondering if a 12.5 is to much foc for a beman ics 400 at 28 inches, fletched with feathers and tipped with thunderhead 100, my arrows seen to start dropping off quick after 25 yards.

RE: question about FOC
 

check out http://www.huntersfriend.com/arrowhelp/arrow-selection-2.htm I think your FOC is a little high. Tinker with some arrow lengths and heads to get it within specs.I think around 9% is the magic #...dont quote me. Good luck too ya.

RE: question about FOC
 

Ideally you need to be in between 8 and 12%. Check out Eastonarchery.com for downloads on arrow selection.

RE: question about FOC
 

Wow, 8-12 sounds pretty low for a hunting arrow to me. Maybe for mechanicals, but for fixed heads I would want more than that. I mean 12% would be ok, but 8 sounds low unless your bow and arrows are tuned really well.

Paul

RE: question about FOC
 

If my bow is tuned and my arrows are grouping broadheads good , I could give a rip what my foc is. Give me a setup with an foc of 8 and I'll get it shooting nocks off. Give me a setup shooting an foc of 15 and I'll get it shooting nocks off. See my point?:eek:
FOR the OVERLY CONCERNED ;)

RE: question about FOC
 

I'd be more inclined to think you've got a tuning issue that's making your arrows nosedive rather than the arrow's FOC %. Like maybe your nock point is too high? Or maybe your bow just isn't capable of driving an arrow flat to 30 yards, with your draw length at your draw weight.

If all is as it should be... bow properly tuned and you're not dropping your bow arm when you shoot, for instance... just use your 30 pin once you get beyond 25 yards. If you're using a single pin setup, sight it in at 27 yards and that should put you close at all distances up to 30.

I certainly wouldn't advise going lighter on broadhead weight. Your arrows are awfully light already, IMO. I think hunting arrows should never be below 400 gns.

RE: question about FOC
 

I'm with Art on this one. I'd look for bow tune also. 12.5% is not too high by any means. In fact it's almost ideal.

Of course any arrow is going to start dropping off pretty well after 25 yards, even with field points. That's what they do. And the slower your bow is the more they will drop. You can normally look for about 6" drop from 20 to 30 yards with a bow shooting about 250fps or a little more. THAT'S WHAT ARROWS DO!!!!!!!!!!!!!!!!!!!!!!!

RE: question about FOC
 

foc has to do with the balance of the arrow...what does mech,or fixed blade heads have to do with that?Also you CAN have a 540gr arrow with an 8% foc....You can have a 350gr arrow with 14% foc...7-15% is the accepted range with 9-10% being ideal.Your arrow is only about 377gr.It shouldn't be dropping off @25yds(I'm using one pin from 0-40yds with field tips,my arrow weighs the same as yours,but I'm not sure of how fast your bow is going)..The feathers are the reason why your foc is high,they are very light.It is still in acceptable range,but it is a hair high.So you can balance it out by dropping your tip.An 85gr tip will put you with an 11.1% foc,weighing in at 362gr.75gr tip will give you an arrow weight of 352 gr,andgive you a 10.1% foc,and is what I would recommend.OOps...what poundage are you shooting?352would bescraping bottom for a 70# bow.In that case I would go back to vanes,and keep your current head.That would put you at 394gr,and an foc of 10.1%.AND WOULD GIVE YOU A PERFECT BALANCE OF SPEED,AND ENERGY.Rocky mountain has a great 75gr head.It is called the Premier..it's a fixed blade head.Wasp has a variety of 75gr heads also..Hope I helped.

RE: question about FOC
 

Hi guys, thanks for all the replies and info, my bow setup is a darton vapor, draw length is 29 and i'am shooting 63 pounds, through paper i shoot perfect bullet holes and i can keep 3 inch groups out to 40 yards, this only started happening when i went to carbon arrows fletched with feathers, i took a few arrows and fletched them with vanes to lower my foc and it seemed to help some, my aluminum arrows are 10.2 foc and seem to fly alot better and have less drop off than the carbon arrows, and the bow is shooting 267 through a chronograph.thanks again for all the replies.

RE: question about FOC
 

Ok cool,then I would go with the 75gr head for sure!!That's 5.5grains per pound,the foc will be 10.1%.It should give you a little more speed too.Maybe 4-5fps...Hope I helped.

RE: question about FOC
 

At what distances are you shooting bullet holes through paper with the new carbon arrows? Or was the paper tuning done with your aluminum arrows?

RE: question about FOC
 

The difference between a mechanical and a fixed blade is the mechanical does not wind plane as bad and flies much more like a field point. Hence more forgiving. You could shoot field points with 6 or 7% foc and do it accurately with enough fletching. I doubt you would have that much luck with a fixed blade that will catch the wind as it flies thru the air. So if you shot mechanicals you could get away with less FOC like a target type arrow and still have it be fairly forgiving. This is why many shoot them, they easier to tune. It's the wrong reason, but never the less it happens.

More FOC forces your fletchings to work harder. This helps your arrow stabilize faster and stay that way. I have never seen too much FOC make an arrow fly bad. I have seen too much tip weight lower spine and make an arrow fly bad though.

What size are your aluminums? If they are bigger than 19xx then the nocking point will not be the same from arrow to arrow because the aluminums are larger in diameter. Going to a smaller diameter arrow without changing your nocking point or adjusting your rest will lower your impact points.

Also by adding weight to the back of your arrow you could have changed the dynamic spine. Adding weight to the back stiffens your arrow.

Is this a problem you are having with a broad head on your arrow, or with field points? I am confused about that part.

A simpler answer is you can't just change arrows and not anything else and expect things to be the same. Sometimes you get lucky, but usually you need to retune your bow.

Paul

RE: question about FOC
 

i had this same problem last fall when changing from aluminum fletched arrows at 28 inches and 125 grain thunderheads to gold tip hunters with vanes and 100 grain thunder heads all with 65 lb draw. i think because i changed broad head weight it made my arrow flight corkscrew after twenty yards. anyways, i asked the guy at the proshop and he threw my arrow with the broad heads on the straightness checker. When rotated every one of my broad heads was wobbly as hell, even the ones i had never shot. That could have been from the inserts not being glued straight/correct or from crooked broad heads. try checking the broad head alingment and adjusting as necessary, or maybe try changing to higher quality broad heads with shorter blades (not cutting hole, blade length). Also are you hunting or target shooting? If you are hitting good groups at forty yards i wouldn't worry about paper testing. Are you gonna be shooting papper or bucks? Bucks don't care if you puch perfect holes. Check that your rest is centered properly and that you nock point is still correct. Streching/wearing strings can change the nock point and travle.
good luck