Noticed a lot of people here use heavy points, like 150 grain plus. What is the benefit? Also, where could I find a chart that shows how to choose arrows with these heavier points? Thanks,
Scott.
Penetration
Download Stu's dynamic spine calculator
Well, if you plan on hunting with the bow,
it is a good idea to shoot a heavy arrow or an arrow as heavy as your bow can shoot accurately.
This is sometimes accomplished by adding a heavier broadhead.
You want some "weight" behind it, if you know what I mean.
Consider 2 identical broadhead arrows dropped from an elevated position straight down into a watermelon.......
One arrow weighs 300 grain and the other 600 grain.
Obviously the heavier arrow penetrates deeper.
If not hunting, it's not so critical.
(not sure if watermelon was a good choice). What do I know, I'm not a scientist!.........Hope I helped a little.....Philip
bow tuning info (http://www.acsbows.com/bowtuning.html)
Here is a link to help you understand how to tune your bow AND arrows. You can do a search for FOC and get some better understanding. You can read the Ashby reports and get an even better understanding. You can play with Stu's calculator and see how different point weights can affect spine. Until you get a feel for it yourself from playing with different arrow combinations live and in person, Stu's calculator would probably be the easiest way to achieve that understanding.
FoC weighting of the arrow. Read Dr. Ed Ashby's writings as advised above. Some of my arrows have 300 grain field points screwed into 100 grain brass inserts. It is also a tool for tuning shafts to a bow, thereby changing the dynamic spine of the arrow whilst also achieving high FoC, which is desirable.
Kris
QuoteOriginally posted by awbowman:
Penetration
Only if it is a narrow head. A wide blade has less penetration than a narrow one.
Put a small head on a heavy, well tuned arrow for penetration (IMHO - In my historical opinion).
I am not a believer in this weight forward movement. Long age Easton came up with the formula that your arrow balance point should be about 11 to 13 percent weight forward.
You have to realize from a logical and a mathematical view this is the ideal arrow set up. Without getting too complicated. Any object here on earth is affected by gravity, so when you have an object that has an initial force applied to it that causes to move forward such as an arrow shoot out of a bow or a bullet fired out of a gun its flight trajectory as it loses speed follows a path call a parabola. The simplest way to describe what a parabola looks like is that as the projectile is traveling fast and its speed is decreasing slowly the downward curve is fairly flat but due to gravity, air resistance, weight of the object the projectile loses speed faster and faster the further it travels. So the curve goes from one that has a moderate curve to a curve that is ever increasing in curvature.( maybe you have seen a flight path of a bullet on ballistic chart)
So now take an arrow that is highly weight forward, the parabola will be one in which that later part of the increasing curve is even more increasing. Thus the cast or the total distance that the arrow will fly is much shorter.
If you want more momentum with your arrow add weight to the arrow equally and still maintain the balance point that Easton came up with.
Never ending story(or Thread)!!!But if it can help those who haven't gone through this than it's useful.
Easton's "theory" is NOT the last word on the subject of FOC weight percentage. I'm with Tradgang member Dr. Ed Ashby and his 20+ years of thorough experimentation on broadhead design and penetration and EFOC. Some of you should read his test results, it makes great sense.
I read the ashby papers and they seemed so logical from start to finish. I haven't tried the high FOC yet but it sees to have alot of benefits in the field not least the arrows ability to correct itself when disturbed in flight. His broadheads are out of my pricerange though, plus I'm not hunting cape buffalo so I don't need that much penetration. I found the comparison between two blade and multiple blade heads very interesting. A "must read" in my eyes
Lightest field point I have is 250gr, use 300gr up front on all my carbons.
It's a personal choice thing. You can harvest any animal in North America with HFOC or with flint and cane. It's what path you choose to follow.
It's the nature of the arrow material you want to shoot.
Carbon arrows don't come in a lot of spines like aluminum arrows do because carbon arrows are very light GPI (grains per inch) wise and very stiff compared to aluminum arrows.
If someone wants high FOC or EFOC arrows, they're "most likely" going to be shooting a carbon arrow. Aluminum arrows, because they're generally heavier GPI (grains per inch) wise and not as stiff as carbon arrows in the same spine range, will give someone a lower FOC arrow.
With my present setup with the aluminum arrows I'm shooting, which you can see in my signature, both bows are shooting 14.1% FOC arrows, but the 37# recurve is shooting an overall arrow weight of 481 grains which is a 13.00 GPP (grains per pound) arrow. I might be able, by adjusting brace height, to get a 471 grain 2212 arrow to shoot out of my 37# bow which will give me a 12.72 GPP arrow, but it will also give me a lower 13.4% FOC.
For me, I like a heavier GPP arrow compared with a high FOC arrow.
Night Wing... We used to add lead to the back of the insert on Aluminum arrows to gain FOC all you really have to do is go up a spine or so and add the weight to the front to break down the spine to what you need.. Nowadays PDP is making weight systems to accomplish the same thing and some folks are making brass insert as well..
then you get high FOC and mass weight.. You don't need to shoot carbon to get EFOC.. although the lighter the shaft in GPI and the shorter the shaft is the more the weight in the tip affects the FOC..
EFOC is kind of wasted on whitetails, but can come in handy on big hogs and the bigger game..
I like around 20% for hunting in Texas..
I didn't start out trying to achieve EFOC, just tried to get the dang arrow to fly straight. I ended up with a 100 grain brass insert and 200 grain points on a Beman MFX 500 shooting out of my bows that are mid 40's in poundage. Arrow flys well, penetrates like the dickens and blows thru everything I shoot. I don't know what the FOC actually is, I don't know what the FPS is and to be honest with you, I don't care. It shoots well, penetrates well and that's really all I care about.
QuoteOriginally posted by Crash:
I didn't start out trying to achieve EFOC, just tried to get the dang arrow to fly straight. I ended up with a 100 grain brass insert and 200 grain points on a Beman MFX 500 shooting out of my bows that are mid 40's in poundage. Arrow flys well, penetrates like the dickens and blows thru everything I shoot. I don't know what the FOC actually is, I don't know what the FPS is and to be honest with you, I don't care. It shoots well, penetrates well and that's really all I care about.
!!!!!!!!!!!!!!! BOOOOM !!!!!!!!!!!!!!!!!
:thumbsup:
QuoteOriginally posted by Crash:
I didn't start out trying to achieve EFOC, just tried to get the dang arrow to fly straight. I ended up with a 100 grain brass insert and 200 grain points on a Beman MFX 500 shooting out of my bows that are mid 40's in poundage. Arrow flys well, penetrates like the dickens and blows thru everything I shoot. I don't know what the FOC actually is, I don't know what the FPS is and to be honest with you, I don't care. It shoots well, penetrates well and that's really all I care about.
That's how we used to do it before Al Gore invented the internet.. :biglaugh:
Crash I am so glad someone said it.I usually go with what works for me...sounds like you do to!!
Same here, the only way to get these carbons I had was using a 50gr brass insert and 200gr point. Found out they easily blew through the average size hogs I was shooting and made it possible for me to shoot some big boars.
Is FOC the end all and be all. No. Does it enhance penetration? Yes. Does it improve arrow flight and recoverability if the arrow hits an object in flight? Yes. Does it impeded arrow flight over long distances? No. Does it decrease arrow flight distance in an equal weight arrow from the same bow? No. Two arrows of the same weight will hit the ground at the same time when fired from a bow at the same angle, height, and draw weight. The EFOC arrow expends less energy in archers paradox osscillations which means it has a flatter early trajectory. How much? Enough to be used to set world flight distance records. OL Adcock has been proving this very recently.
The present long distance flight records are held and are being broken by EFOC and HFOC arrows. The difference here is that long range shooters using EFOC arrows are able to use little or no fletching to control their arrows. This is due to far better arrow flight characteristics from an EFOC arrow.
If you call up the engineers at Easton ( I have ) they will openly admit that their numbers and calculations are based in compound bows and obtaining the fastest speed out of their bows that they can. They openly admit to not knowing or fully understanding HFOC or EFOC and have no intent of pursuing it. HFOC and EFOC arrows weigh a lot more than standard compound arrows and this will not sell those amazing fast bows the wheelie brothers have to have every year.
give them a try, if you shoot enough Game and strive for greater performance for your set-up you will see the benefits of a heavy head for yourself.
sure, you dont need a "EFOC" or whatever to successfully kill something with bow and arrow.
but the benefits are tired and tested there if you want them.
Some people settle for "good enough"
Others push and extend the boundary's for greater performance
makes the world go round...
have fun with it, enjoy the hunting.
Very well said, Ragnarok Forge. I agree 100%! Same goes with Andy Ivy's statements.
Crash - Your arrows are likely in the upper EFOC range (~27%) based on a 29.25" arrow.
Lots of FOC!!
Just had some 300 gn field points modified to accomodate techno-hunt mushroom tips.
32.4% at 608 grains has opened my eyes and hopefully will close some turkey's eyes.
(http://images.imagelinky.com/1300850273.jpg) (http://images.imagelinky.com/1300850273.jpg)
All I can say is "read ALL of Dr Ashby's reports". And, listen to what every one else advises,and make your decisions based on your own shooting tests. For me, with almost 40 years of experience bow hunting, there was a LOT to learn from Ashby. Choose what you want to take away from all of it.
I agree with many that it doesn't take much to kill a deer at close range with a good shot. For me, it's all the gray area that's caused the questions. When it comes to bow hunting, there are lot of gray areas.(talking about unexpected events, not ethics!)
For me I will most likely never take a shot past 30 yards on an animal. This pretty much eliminates any concerns I might have about trajectory of my arrows. With that said, I always assume that my shot will not hit exactly where I want it to go. Therefore it makes sense to have a higher FOC to get deeper penetration on less than perfect shots.
i use heavy points to weaken the spine to what i need. with my little arms and shooting bows around 45# at my dl i cant really use alot of the arrows with higher GPI unless i move up to a arrow thats stiffer and use a heavy end wieght to weaken it.
my set up right now thats flying awsome from my beeler long bow are cx heritage 90's full length with the standard insert, 250gr field point and 5" left helical feathers. pretty good FOC and wieght for hunting
QuoteOriginally posted by Trumpkin the Dwarf:
For me I will most likely never take a shot past 30 yards on an animal. This pretty much eliminates any concerns I might have about trajectory of my arrows. With that said, I always assume that my shot will not hit exactly where I want it to go. Therefore it makes sense to have a higher FOC to get deeper penetration on less than perfect shots.
same here. i dont plan on shooting past 20yds at deer with trad gear for a while. i want to shoot a heavy arrow just incase things dont go perfect and bone gets involved.
I love efoc. I use 400 grains up front total arrow weight is 750. Flys great and hits very hard. The last 3d shoot that I went to, the other shooters would joke about how hard it was to pull my arrow out of the target because it would penetrate so much more than the other arrows.
Gilbert
I thought I'd play with the Ashby EFOC or ultra FOC arrows. Bought some suggested Griz Safaris. What I didnt realize was that my draw length of 31.25 is too long to put 300gr Ashby heads in front and get good arrow flight. Everything fly nock left. So my question is......are there shafts long enough and stiff enough to shoot these heads with? 70# Qarbon Nano
"Also, where could I find a chart that shows how to choose arrows with these heavier points? Thanks,"
Just to steer back to the other part of the original question,I don't think there is a chart and Stu's calculator doesn't help much when you are talking about a lot of front end weight.
The bow tuning info link that Rastaman gave you will give you some idea.Depending on how much weight you want to add,you may have to start with a carbon shaft one or two spine groups stiffer to compensate for the weakening affect of more front end weight.
A rough rule of thumb would be 1" of shaft length= app 5lb of spine and app 17-25 grs of point weight would also equal 5 lb of spine.This would get you in the ball park for what shaft you want when you change point weight-either direction.
From there,it is to the range and the usual bare shaft tuning till you get the right combination of shaft length and whatever point weight you like.
I chose approx. 200gr. broadheads because that weight can be achieved with some combination of glue on broadheads and adapters. With a addition of various inserts and/or screw in weights, I can bring my total up front weight to around 300 gr. Considering the weight of most carbon arrows I shoot, I need something around that weight to get the total arrow weight I want. Might not be sound reasoning, but works for me.