Let's talk broadhead physics

[Draco]

I don't think you are at 40% foc. It's really difficult to get past 20% and Dr. Ashby calls 25% extreme foc. If you do you should be getting more penetration than the rest of us though.

[jreyna920]

My gold tip 3555's would need 1700grs up fornt to get me to 40%

[meangene1969]

John that might be alittle heavy.

[fletcherfor2]

My gold tip 3555's would need 1700grs up fornt to get me to 40%

You'd need a Ballista to launch that sucker.

That would be kind of like a hand-held gatling gun. You'd have to be Arnold ("Predator") to pull it off.

[Mike Javi Cooper]

according to my calculations.. a 29" BOP 35/55 GT Trad would need 1200 grains up front using 3 5" feathers and a standard GT nock... to get 40% FOC...

[Greywolf in Hawaii]

A while back they found a bunch of flint heads that were smaller than conventional size we think of. So they concluded that those "must have been bird broads" but further findings they discovered they smaller heads were used on bigger game "smaller heads penetrate deeper" due to the smaller cutting edge. the larger heads were thought to be for birds instead.

Dr Ashby also went into great detail on KE verses Momentum too, sometimes those two get discussed in the wrong context. The cutting of the blades are KE... how far the heads goes in is momentum.

I'm sure the American Indians didn't worry about KE or Momentum, they did how ever worry about tuned arrows Arrow no fly good.... make another !!! was all they cared about

[Wudstix]

I just use 160 and 190 grain Ribtek, big hole and strong heads.

[fletcherfor2]

A while back they found a bunch of flint heads that were smaller than conventional size we think of. So they concluded that those "must have been bird broads" but further findings they discovered they smaller heads were used on bigger game "smaller heads penetrate deeper" due to the smaller cutting edge. the larger heads were thought to be for birds instead.

Well this is new information.

I've seen the flint "bird" points. I've seen them called bird points. I still thought they were bird points.

I didn't know that the perception of their use/ nature had changed. It must have been fairly recently.

[LeanMachine]

I have heard the same thing too about the smaller heads. It only makes sense. They shot very light weight bows into large targets.

[bm22]

I don't think you are at 40% foc. It's really difficult to get past 20% and Dr. Ashby calls 25% extreme foc. If you do you should be getting more penetration than the rest of us though.

I put my specs into an foc calculator on goldtip.com and i did the measurement formula to and they were about the same, i shoot over 400 grain up front on a 30 in shaft that weighs 6.5 gpi. They are supposed to have kevlar in them and are very stiff. When i get time and find my grain scale i will take a look. I need to tweak things anyway for next season.

[Greywolf in Hawaii]

Well this is new information.

I've seen the flint "bird" points. I've seen them called bird points. I still thought they were bird points.

I didn't know that the perception of their use/ nature had changed. It must have been fairly recently.

Yeah, your probably right..... after 35 yrs of this stuff..... won't be the first time I was wrong.

[fletcherfor2]

Yeah, your probably right..... after 35 yrs of this stuff..... won't be the first time I was wrong.

I was not disagreeing with you Stic...I remember seeing those little bird points at a museum in San Antonio probably 20 years ago. Their use may very well have been "reinterpreted" since then, as you said.

Hey, I've been wrong about many things on here. I try to make a point of not posting on a subject any more if I'm not pretty sure.

Steve (Texas50) is an expert on this stuff. He'd know their purpose if anyone would.

[Mike Javi Cooper]

True or not... who knows but here it is in writing..

Myth Number 2: The smallest arrowheads were used for killing birds.

Experimental archaeology has shown that so-called 'bird points'--even those under a half inch in length--are plenty lethal enough to kill a deer or even larger animal. These are true arrowheads, in that they were attached to arrows and shot using a bow. An arrow tipped with stone would easily pass right through a bird, which are more easily obtained using a net.

http://archaeology.about.com/cs/lithics/a/thepoint.htm

Shown here are two exceptionally large "bird points". They are 2-1/4" long and very thin. The term "bird point" is a misnomer. They were probably true "arrowheads" since they have been found in deer and bison remains and were probably used for both hunting and warfare. The bow and arrow is believed to have been introduced in the Late Prehistoric period (700 AD to historic times.) Prior to the bow and arrow the atlatl spear (or dart) and the lance, both employing larger lanceolate points, were used. Shooting a bird on the wing with a bow and arrow seems unlikely - a turkey or prairie chicken on the ground - well, maybe.

http://www2.itexas.net/~teddun/tedspage.htm

[fletcherfor2]

Myth Number 2: The smallest arrowheads were used for killing birds.

Shooting a bird on the wing with a bow and arrow seems unlikely - a turkey or prairie chicken on the ground - well, maybe.

Well they must not have seen "The Book of Eli" then...LOL (This is just a joke guys)