Mike — You’re way over my technical level with all of this, so not much I can offer. Except to say that I have some of the same shafts and simply keep loading on weight up front and see how far I can get away with it. With shafts cut to 29″ bop for my 28″ draw, so far I’ve never exceeded spine and the more weight up front, the better they shoot. I’ve settled on a setup that provides 680 grains total with 26+ FoC.

Down at my low-tech level of experimentation, while Ashby’s data can be made to argue that FoC is even more important than minimal bone penetration arrow weight, which he puts at 650 grains, I don’t see it that way in my experience with elk. I say get that 650 first and foremost even if it means going to a heavier shaft that reduced FoC. But there’s really no reason we can have both with carbons. It’s all fun. dp

Mike — My bows are 55, 53 and 51# and I shoot the same 680 grains out of all three (and some even heavier woodies). Read Ashby’s latest update, posted here in the Ashby library, which shows (along with previous reports) that the lighter the bow draw weight, the more positive difference in penetration heavy arrows and high FoC make. Besides, it’s something fun to do, these experiments, when we can’t be hunting. dave

what’s BOP?

Back Of Point shaft length,that is, the standard way of measuring a shaft, from bottom of nock to back of point.

ok…didn’t know there was an actual term for it…just knew that you measured from the bottom of the nock to the end of the shaft…learn something new every day…just gotta ask questions to get answers, right?

Michael.

Michael and Dave — I’ve never heard it as an acronym or term either, but it works. I guess we have too many words in the English language, as we all seem to want to shorten them down when possible. The military is the worst. But hey, DILLIGAS? 😆 Snuffy

MontanaFord,
There is more than one way to measure arrow length for FOC. However, the AMO standard measurement is from nock groove to end of cut shaft, not including insert, adapter, point, etc.

My latest hand loaded arrow for my 71@31 BW is 978 gr and 36.6% FOC.

Just for the hec of it I took out my other arrows, CX Predator II arrows with 145 field tips up front and spined 0.600. Felt like I was shooting tooth pics compared to my GT expedition hunters with 100 gr brass inserts and 300 gr field tips.

Mike,
Yes those arrows fly very well and hit really hard. The trajectory is only minutely different than the 860ish grains that I also shoot.
What I have found is that when you get over about 30% FOC the arrow is so forgiving that an increase in point weight, trajectory and speed seem to not change arrow flight.

For example, I just made up a 755 gr arrow including a 319 grain point and 31% FOC. I simply unscrewed the 319 point and screwed in a 406 gr. point, increasing FOC to 33%. The arrow flight of the arrow is the same with either point. It does not show weak at all. To my eye, the trajectory is exactly the same for 17ish yards and only slightly and insignificantly differently farther out.

So many reasons to increase FOC as much as you can.

sapcut,

can you give us the specs on the arrow pictured above? i’d like to see what all you used to get where you’re at. thanks.

Michael.

MontanaFord,
The arrow pictured above is as follows:
Shot from Black Widow PSAX 71@31

Gold Tip Ultralight Entrada 300
262 gr. 31″ from nock groove to cut carbon
210 gr. Grizzly El Grande
200 gr. adapter
100 gr. brass insert
30 gr. 2.5″ 2117 footing
27 gr. 2″ 2317 footing
9 gr. nock (after cutting 1/8″ off male portion)
6 gr. 3 – 4″ nanners
8 gr. glue

852 gr. 34.07% FOC

These are the pictures of the insert, adapter and footings

The 2117 footing fits flush with the end of the carbon against the bottom of the insert collar. The 2317 fits over the 2117.

This is the 2317 footing extending over the 2117 footing and beyond the insert collar

This is the extended broadhead adapter to fit under the footing

This is where the adapter shank hits the first thread of insert

This is the adapter screwed down tight as the broadhead reaches the tapered end of footing

This is how everything looks under the footing providing strength and a smooth transition

Hopefully living happily ever after.:lol:

sapcut,

Did you make your own broadhead adapters or are they factory jobs? thanks for the detail pictures of your set-up. gives me something to think about while I work on my own arrows for my bows.

Michael.

I make them out of field points. I make them from 160 gr. to 270 gr. They work really well.
One of the best benefits is that the heavier ones allow for 1″ extra draw clearance. That allows me to cut the arrow up to 1 inch shorter than normal giving me a stiffer arrow. That of course allows for supernatural front loading like I like it.
My 978 gr. arrow has a 270 gr. adapter included in the
685-700 grains up front.

Richie

This is very similar to Kingwouldbe’s set-up with alum sleeving over carbons shafts. I don’t know if he uses an internal weight-adaptor or not. But in both cases I’m left to wonder if the “bump-ups” over the sleeves don’t distract when you approach full draw, and don’t affect accuracy as they bump back over the shelf on release? Or do you leave enough length up there so that you don’t draw onto the sleeves? Very nice illustrations, thanks. dp

Dave,
The tapered edges of the footings are noticed only the first few times drawing the bow. After that I do not notice it at all and it certainly does not affect accuracy.
Since going to this type of Ultra-EFOC setup, I have never been as accurate shooting my bow.

Yes, I saw a picture of King DeVille’s arrow a while back.
It got my thinking about just how lethal I can get an arrow. Unfortunately, I can’t seem to stop the “arrow scientist wannabe” madness.

Richie

sapcut wrote: I make them out of field points. I make them from 160 gr. to 270 gr. They work really well.
One of the best benefits is that the heavier ones allow for 1″ extra draw clearance. That allows me to cut the arrow up to 1 inch shorter than normal giving me a stiffer arrow. That of course allows for supernatural front loading like I like it.
My 978 gr. arrow has a 270 gr. adapter included in the
685-700 grains up front.

Richie

Richie

Can you tell us how you shape the field points?

Tom

Tom,
First, I use the more pointed field tips, not the rounded blunt type. I grind down the front, just eyeballing as I taper it to the shape of the ferrule.
I try to only use the front 1/2″or so (from the point) so I will have as much area as possible behind the broadhead for draw clearance.

The pictures show a small and large adapter.

Richie,

Thanks for all the information on how you manage to achieve such a high FOC. That’s very helpful. What is your preferred broadhead for your hunting? What all, and where, do you hunt? Thanks again. So much information to process and put to use.

Michael.

Michael,
I haven’t had the experience most here have had using many different broadheads but I like the Grizzlys. I have recently acquired a few abowyer large boneheads to try but my preferred is the Grizzly. I hunt whitetails and hogs in South Alabama as well as elk in SW CO the last three years.

Recently got some easton Flatline arrows, at 340 spine and 8.2 gpi. With a 1.5″ 2117 footing, a 2315 1″ over this. A 100 grain brass insert 100 grain steel adapter and 200 grain grizzly I am able to get 32.5% FOC. Total arrow weight is 670 grains. This arrow still gives me very good trajectory out of a 60# curve it hits super hard and will be some bad medicine for the elk this year.

Now you’re cookin with gas:lol:…..
That medicene will leave a mark.

The Ultra EFOC has a lot to do with trajectory staying flatter than expected compared to the same weight arrow with average FOC.
There is a difference. It’s a Win Win difference.

Mike,
That is correct. The UEFOC arrows shoot flatter than you would think.
I know from the arrows I have hand loaded and shot that the heavy 30-35% arrow shoots flatter over a longer distance than the same total weight arrow with 19% FOC. Not a huge amount but it is noticeable and significant. No doubt in my mind.

Out of MY quiver…a 900 gr 30+% FOC arrow has a very very similiar flight path or trajectory as a 750-800 gr arrow with normal 20ish % FOC.

In the recent past I would not do this but now I am comfortable shooting a 900-950 gr. 34% FOC arrow out to 35 yards because it is like shooting my elk arrows that were 770 grains but only 19% FOC.

It really surprised me in the beginning so I asked Dr Asbhy if I was seing things or if it was really happening. He said it is true, that he had discovered the same results. He also mentioned (in a thread somewhere here) that he conducted a demonstration at an outdoor/hunting event showing how the high FOC arrows will travel flatter. He used a rubber washer on an arrow that he could slide along the shaft. When he put the washer way up front creating Ultra EFOC, the arrow would hit the back wall of the building. With the lower FOC, the arrow would not go as far hitting the floor in front of the wall. That is what I remember from what he said.
Maybe someone can find that stinkin thread.

Richie

Mike,
I’m shooting 71@31.

Remember to begin the building process with a stiff, lightest grain per inch arrow you can find. That allows YOU to make the arrow heavier by loading up the front. Then, of course the front weight will weaken the stiff arrow back to a tuned arrow with Ultra EFOC. Wha La.

Richie

Richie,

I remember Dr. Ashby’s post about his demonstration. The first shot was with the rubber washer near the center of the shaft…about 6% FOC…your average FOC for compound shooters. The second shot was with the rubber washer farther forward, approximately 13 or 16% FOC, the average for traditional shooters shooting aluminum or wood arrows. The last shot was something like 23 or 24% EFOC, and that’s the one you’re talking about that hit the far wall of the lecture hall. And all he used for a launch mechanism was some sort of bungee cord. The “shaft” was a plain-jane, unfletched wooden dowel like you would buy at the hardware store. I don’t remember if he gave a length or diameter on it.

Michael.

Michael — I wish I had your memory for details.

Mike — nice knife in your avatar photo. Is that a Helle? For last year’s elk, last day of the season, I somehow forgot to bring my Helle belt knife — 3″ blade, 6″ overall. So I had to do the entire job with a self-handled 2″ Helle blade, 4″ overall backup. No problem in the doing but I sure had sore muscles in the knife hand and wrist for a few days! dave

I’m fortunate, Dave. A lot of stuff I read or seriously take an interest in, I remember like nothing else. My wife swears up and down that I don’t have any memory at all, because she’ll tell me something, and ten minutes later, she’ll ask me what she said, and I’ll say “I don’t know.” Or we’ll have an argument about something, and later she’ll say she said this or that, and I’ll say, “No you didn’t. You said this.” LOL. I get myself in so much trouble for not paying attention when I probably should be. But if it’s something I’m keenly interested in, I generally can remember the details. It makes her mad. I just laugh about it, but to myself. lol

Michael.