FOC / long arrows

[wayoh22]

Because your numbers are Wrong.
Axis 250 is 9.8 gpi
FMJ 250 is 11.5 gpi

They don't make the Axis in a 250, it's 260. And now I'm even more curious as to where you're getting your numbers from. Straight from Easton's Website with links to each:

Also, not trying to sound like a a**hole, I'm genuinely curious.

https://eastonarchery.com/arrows_/5mm-full-metal-jacket/

5mm Axis Carbon Arrows - Easton Archery

The hands-down proven small diameter all carbon arrows. Micro diameter focuses energy into a small frontal area for less friction and greater penetration.

eastonarchery.com

 

[Beendare]

I think the Axis 5mm black are 11.5GPI in 260 spine, I know the 300 spine that I shoot in my compound is 10.7
Re 32” arrows, I am pretty sure the Axis Trad shafts come uncut 33 inches. I shoot a 31 1/4 inch Arrow Inn my recurve and I have to cut the shafts down.

Plus I also shoot the Beman Centershots in wood grain and those come 32 inches I think

edit- ok you beat me to it With the chart above.

 

[Reburn]

They don't make the Axis in a 250, it's 260. And now I'm even more curious as to where you're getting your numbers from. Straight from Easton's Website with links to each:

Also, not trying to sound like a a**hole, I'm genuinely curious.

Because your numbers are Wrong.
Axis 250 is 9.8 gpi
FMJ 250 is 11.5 gpi

Cool everyone. Im sure he meant axis 4mm. It comes in a 250 and weighs 9.8
5mm axis is in fact 11.5 gpi

4MM Axis Long Range & Match Grade

eastonarchery.com

Most people here dont like the FMJ because they can flex and end up with a permanent bend. unlike carbon that will spring back and you just flex it.

 

[wildwilderness]

Yes, the 4mm axis is as stated.

The other point is the 250 FMJ is an anomaly in gpi. It is actually lighter than the 300 spine and about the same as the 340. So the general rule is FMJ is heavier than 4mm or 5mm Axis in the shaft. Thus the suggestion to increase FOC by picking axis over FMJ. Most archers don’t deal with the stiffest spines and would notice that anomaly.

 

[Billy Goat]

The question is what did Easton due to the 260's? They must be heavier on carbon, lighter on aluminum than other arrows in the fmj line. How else can they be lighter than the 300's? Pretty sizeable jump in O.D. from the other sizes. Maybe it's actually the diameter that gives them the spine rather than the material thickness. That's not uncommon with aluminum.


Either way high gpi is bad for foc.



@Kbhillhunter what arrows were you previously shooting anyways?

 

[Kbhillhunter]

The question is what did Easton due to the 260's? They must be heavier on carbon, lighter on aluminum than other arrows in the fmj line. How else can they be lighter than the 300's? Pretty sizeable jump in O.D. from the other sizes. Maybe it's actually the diameter that gives them the spine rather than the material thickness. That's not uncommon with aluminum.


Either way high gpi is bad for foc.



@Kbhillhunter what arrows were you previously shooting anyways?

Gold Tip Hunter XT 250, 32.5" c2n, 150grs up front. By my math was just shy of 12% FOC but at 525grs I had them flying at 275fps which seemed to do the trick.

I'm looking at these Black Hawk Carnivore shafts. GPI is a little lower at 9.7. If I can cut 2" off my total length that might give me the room I need to add a little more weight out front. I've been messing around with the spinal tap program and that's at least what I've been able to come up with using that.

 

[Billy Goat]

Gold Tip Hunter XT 250, 32.5" c2n, 150grs up front. By my math was just shy of 12% FOC but at 525grs I had them flying at 275fps which seemed to do the trick.

I'm looking at these Black Hawk Carnivore shafts. GPI is a little lower at 9.7. If I can cut 2" off my total length that might give me the room I need to add a little more weight out front. I've been messing around with the spinal tap program and that's at least what I've been able to come up with using that.

Those shafts are in stock at Lancaster Archery. If you don't feel like changing.

I shoot GT hunters and the BE Carnivores, both good arrows.


I'm not positive, I have always actually found foc rather than calculate, but I don't know that your foc would actually be that high with those arrows. Did you balance the shaft and measure it, or use a program? But again, I wouldn't care what the foc actually is, assuming it's 10 or close to it.

 

[Brendan]

I think you're on the right track, and Others saying it too - Consider cutting your arrow shorter. I run 27.5" c-to-c with a 29.25" draw and my broadhead is still over the shelf with room for a collar / footer and no rest interference. So, almost 2" shorter than draw length... Depends on your rest.

But, look up torque tuning while you're at it. It's a process of setting the front/back position of your rest and sight to make your bow as forgiving as possible. I use that in combination with my sight to set my rest position and get a torque free bow. That sets the rest position, and tells you how short you can go on your arrows.

 

[Kbhillhunter]

Those shafts are in stock at Lancaster Archery. If you don't feel like changing.

I shoot GT hunters and the BE Carnivores, both good arrows.


I'm not positive, I have always actually found foc rather than calculate, but I don't know that your foc would actually be that high with those arrows. Did you balance the shaft and measure it, or use a program? But again, I wouldn't care what the foc actually is, assuming it's 10 or close to it.

I punched the specs into the spine program and it turns out it was actually closer to 10%, I must have screwed my math up.

 

[Reburn]

I punched the specs into the spine program and it turns out it was actually closer to 10%, I must have screwed my math up.

IMO 10% still good. You want 15-20% FOC in a long arrow?, prepare to have an insanely light shaft that wont be durable and a heavy head with semi moderate FPS or a heavy shaft with a heavy head with slow FPS and trajectory that looks like a rainbow. FOC is the LAST thing guys with long arrows should be concerned with IMO.

 

[5MilesBack]

Can you explain how you came to both those conclusions? If he was to go with the Axis he'd be a 260 spine. Compared to the FMJ 250 spine, they're identical in weight at 11.5gpi. With all other things being identical besides the FMJ just being composed differently I'm not understanding how you came to that.

It used to be that the FMJ's were heavier than the Axis in similar spine. Their chart doesn't add up. Why would the 250 be almost the same gpi as their FMJ 340? And even though it says the shafts are thicker diameter, it says they take a 17/64's point. None of that makes any sense. The 250 should be at least 12.5gpi.

 

[Kbhillhunter]

IMO 10% still good. You want 15-20% FOC in a long arrow?, prepare to have an insanely light shaft that wont be durable and a heavy head with semi moderate FPS or a heavy shaft with a heavy head with slow FPS and trajectory that looks like a rainbow. FOC is the LAST thing guys with long arrows should be concerned with IMO.

Well ideally I just want more of what I'm already using which I have no issues with, I was just trying to see if I had more options using what (little) I've learned since the last time I was looking for arrows.

I took some measurements last night and it looks like with my rest I could cut my shafts down to at least 30.125" and still have .5-1" past the rest. I always assumed I needed full length 32.5" arrows because of my DL, which combined with spine was my most limiting factor in arrow selection.

i don't want to be a slave to FOC I'm just curious to understand the mechanics. At 10% last year I had arrows in two whitetails pass threw from front shoulder to rear opposite quarter, and still had the arrow travel far enough to lose it. So I tend to agree, I think 10% was on the money for my set up.

to be honest, it's February and I'm slowing down at work finally. I am looking for new things to complicate my free time after my son goes to bed haha.

 

[Billy Goat]

Someone else said it, but Easton has spent more time and money on arrow development than anyone, the numbers they have work. I'd go by what they say. 10-15% on a hunting arrow.

WHAT IS F.O.C. AND HOW DOES IT AFFECT ARROW FLIGHT?

In the archery world, F.O.C. stands for “front-of-center.” FOC describes the percentage of the arrow’s total weight that is located in the front half of

eastonarchery.com

Some guys are trying to reinvent the wheel. I have played with it a little, I'm hard headed and need to learn stuff for myself. I'm in agreement with Easton.

 

[Kbhillhunter]

I think you're on the right track, and Others saying it too - Consider cutting your arrow shorter. I run 27.5" c-to-c with a 29.25" draw and my broadhead is still over the shelf with room for a collar / footer and no rest interference. So, almost 2" shorter than draw length... Depends on your rest.

But, look up torque tuning while you're at it. It's a process of setting the front/back position of your rest and sight to make your bow as forgiving as possible. I use that in combination with my sight to set my rest position and get a torque free bow. That sets the rest position, and tells you how short you can go on your arrows.

Thanks! I hadn't considered that. In the past when I started messing with my rest things got squirrely but I think my form has improved enough that I could give this a shot.

 

[Kbhillhunter]

Someone else said it, but Easton has spent more time and money on arrow development than anyone, the numbers they have work. I'd go by what they say. 10-15% on a hunting arrow.

WHAT IS F.O.C. AND HOW DOES IT AFFECT ARROW FLIGHT?

In the archery world, F.O.C. stands for “front-of-center.” FOC describes the percentage of the arrow’s total weight that is located in the front half of

eastonarchery.com

Some guys are trying to reinvent the wheel. I have played with it a little, I'm hard headed and need to learn stuff for myself. I'm in agreement with Easton.

I read that early on and let that guide my search last time. It's good advice. Thankfully my DL isn't any shorter, not sure what I'd do if had even more choices.

Thanks for passing along the link from lancaster. Having my shop fletch the bare shafts might be the way to go.

 

[cured_ham]

If you are shooting a 31.5 draw length why wouldn't you just cut it shorter to 30 or 30.5? That would help a lot.

 

[Kbhillhunter]

If you are shooting a 31.5 draw length why wouldn't you just cut it shorter to 30 or 30.5? That would help a lot.

After doing some research I agree, I definitely have at least a few inches I can trim off and it opens my options up big time. A whole new rabbit hole to jump into haha.

 

[5MilesBack]

You could probably even shoot 300's if you cut the arrows down. When I shoot 60lbs I use ~.340 spine arrows with 125's cut at 30", even at my draw length they fly amazingly well.

 

[wayoh22]

Yes, the 4mm axis is as stated.

The other point is the 250 FMJ is an anomaly in gpi. It is actually lighter than the 300 spine and about the same as the 340. So the general rule is FMJ is heavier than 4mm or 5mm Axis in the shaft. Thus the suggestion to increase FOC by picking axis over FMJ. Most archers don’t deal with the stiffest spines and would notice that anomaly.

I see what you’re saying. Never thought of it like that. Thanks for taking the time to explain


Sent from my iPhone using Tapatalk

 

[cured_ham]

I shot .250 Carnivores with 425 up front (loooooong footer) at 30.5@70 and they tuned. 30" Carbon

I am currently shooting VAP 250s with the Valkyrie system. 29 inch carbon with 230 up front. 30.5 @ 80lbs

Getting the carbon as short as possible helps a ton.