Primitive Archer
Main Discussion Area => Arrows => Topic started by: Rhinegold on October 14, 2009, 12:25:42 pm
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I started using a heavier steel bodkin point a week ago for target practice, and am wondering how altering the point of balance affects accuracy.
Is there an optimal point of balance relative to arrow length as a universal rule???
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I noticed that my arrows the large wooden blunts and the ones with meatal broadheads fly better than the ones with wooden selfpoints.I dont know none of the what is optimum but weight foward of center does make for a more accurate arrow
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changing the weight forward to a larger/heavier point can affect spine
if i remember right more forward weight/heavier point = less spine from same arrow with lighter point
or i could be talking out my backside,i havent decided yet
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Point weight affects balance, or FOC as it's known and calcualted now. Basically, yes. A heavier point will make a more accurate arrow if the overall weight of the arrow isn't too much and the dynamic spine hasn't become too weak. Some bowhunters prefer a VERY high FOC, escpecially with carbon arrows. With wood and other arrow materials you should find it isn't as necessary. Cane, being light and rigid as well, might also benefit from a high FOC.
The "sweet spot" is 10%-15%. To find your FOC find the balance mark. Measure from that point to the middle of the arrow (from the throat of the nock to the back of the point). This should be a few inches, let's say 3". You then divide that by the arrow length, let's say 30", and get your FOC- 10%. That's acceptable.
An example of what an effect FOC has: I had a set of arrows. With 125 gr blunts they flew wonderfully! As soon as I point similiar weight broadheads on them... all over the place. COuldn't call my shots at 15 yards! I switched to 175 gr points and, even though they are slower and won't shoot as far, they are more accurate now.
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I have had some arrows that did not fly right, but when I changed the weight of the point they flew much better. A heavier point will settle an overspined arrow down.
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The "sweet spot" is 10%-15%. To find your FOC find the balance mark. Measure from that point to the middle of the arrow (from the throat of the nock to the back of the point). This should be a few inches, let's say 3". You then divide that by the arrow length, let's say 30", and get your FOC- 10%. That's acceptable.
Very helpful Kegan...with this method I'm calculating 27%.
Bodkin points are WAY heavier than a modern broadhead.
Designed in medieval times to penetrate chainmail.
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Chris Cade, myself and a few other people have solved the same problem by shooting longer arrows. Shooting 34- 36"arrows I can switch between lighter weight bows and heavy ones by tweecking different weight broadheads. This is with Tonkin Bamboo.
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I made 42 white ash selfnocked arrows tipped with hand ground hand made trade points, over a year ago. The spine weights were fairly uniform (75-85) but the finished arrow weights varied over 100 grains. These arrows shoot out of every self and backed bow I have really well, and I can"t out shoot the arrows out to 40 yards even with 100 grain differences. I think the very heavy points are making the difference. Just my observation.
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The "sweet spot" is 10%-15%. To find your FOC find the balance mark. Measure from that point to the middle of the arrow (from the throat of the nock to the back of the point). This should be a few inches, let's say 3". You then divide that by the arrow length, let's say 30", and get your FOC- 10%. That's acceptable.
Very helpful Kegan...with this method I'm calculating 27%.
Bodkin points are WAY heavier than a modern broadhead.
Designed in medieval times to penetrate chainmail.
There are a number of archers out there who are very interested in EXTREME FOC. Most of them seem to be using either tapered arrows or carbons, but they they all seem to say that the arrows are more forgiving and accurate. The only thing that can be said against that would be that they would be nose heavy. Itf that's an issue is up to you though.
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Sailordad you are correct. Heavier points lessens the spine of the shaft.
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Dr Ed Ashby did some penetration test and he said that arrows with an extreme FOC (forward of center) balance point will increase penetration. But he was testing his arrows on big, heavy-boned animals like water and cape buffalo. I would think that a reasonable compromise with our bows and arrows would be perfectly adequate on deer-sized game. From my experience, perfect arrow flight is the number one goal I shoot for.
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Dr Ed Ashby did some penetration test and he said that arrows with an extreme FOC (forward of center) balance point will increase penetration. But he was testing his arrows on big, heavy-boned animals like water and cape buffalo. I would think that a reasonable compromise with our bows and arrows would be perfectly adequate on deer-sized game. From my experience, perfect arrow flight is the number one goal I shoot for.
...pun intended, right? ;)
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Can anyone think of a disadvantage to extreme FOC?
What would be the downside to a FOC of say, 50%?
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I'm not sure what you'd have to do to get to THAT point, but higher FOC's, as Billy said, can help.
It works like a dart. A heavier point makes it easier to throw. Likewise, in flight the heavier point resists the archer's paradox more than a lighter point. So the arrow striaghtens out a little faster- if it's matched to your bow, this means more retained energy and a straighter flying arrow. They require less fletching as well, which means a faster arrow (provided the higher FOC didn't cause the arrow to become too heavy).
I've seen some shorter arrows with as much as 30% FOC, but I think trying for 50% would be pushing the reasonable window. But who knows? Maybe if you get it going it will be a great arrow.