Fun with High FOC/EFOC/UFOC Arrows

[dennis502]

I finally decided to take the plunge and build out some high FOC arrows. I’ve read the reports (Ashby et al) and see the potential merit, so I started researching options.

First, I wanted a small diameter shaft with the lightest GPI possible. After studying all of the charts, the (at the time) soon to be released  Victory RIP XV shafts looked ideal. Narrow diameter (.204”) with light GPI (5.9gr/inch for the .400 spine).

I patiently awaited their release and, 2 weeks ago, secured a half dozen of each in .400 and .350 spine.

I built up 2 different arrows for 2 different bows. Both 60” Schafer Silvertip Recurves,  one at 51# at my 28” draw and the other is 61#.

I started first with the 51# Silvertip. This bow is primarily used for 3D shooting, so I wanted a somewhat lighter arrow than I typically use for hunting. My goal was a 9 GPP (grain per pound) arrow with as high an FOC as I could get.

I wanted to stick with a 200 grain head as that’s what I’ve been using for years and already have a stockpile of 200 grain heads/broadheads. So, the biggest variable in building these arrows is in the options for inserts. Among the options:   
          -stock 21 grain aluminum Shok half outserts
          -Victory stainless steel 60 grain Shok half outserts
          -Easton Axis 75/50 grain break-off inserts
          -Easton Axis 16 grain aluminum inserts
          -Axis 100 grain brass inserts from 3 Rivers
          -Firenock AeroInsert 55 grain
          -The new Gold Tip Ballistic Collar system for their Kinetic Pierce shafts

I set up a spreadsheet with all of the variables and it looked like something around 50-60 grains would be ideal. The Victory half outserts that came with the shafts looked like a decent design. While I’ve always eschewed anything other than an insert, these seemed to be well designed and might preclude the need for an external footing (something I do to all my carbon shafts). These stock inserts were aluminum, so I ordered a set of Victory’s stainless steel version as they would be both stronger and right at the weight range I thought I needed.

I spent several days bare shaft tuning. I took my time, cutting off as little as a 1/16” at a time toward the end, and got them shooting like darts. I stopped cutting when they were just SLIGHTLY weak, as adding fletching would stiffen them somewhat. I fletched  a few up and continued to tune- I ended up making one more small cut (like 1/16”) after fletching to get them as close to perfect as I’m able to shoot.

Final specs for the arrow setup for my 51# bow:
          -Victory RIP XV .400 shaft at apx. 29 1/8”
          -Victory Stainless SHOK half outsert
          -200 grain head
          -Three 4” parabolic feathers
          -Easton Axis X nock

The completed arrow came in at exactly 450 grains, with an FOC of just over 27%. They shoot like darts- I haven’t shot them enough to definitively say they are more accurate than my standard (non high FOC) carbons but I really like them. I will be shooting this arrow going forward.

I next had to build out for my 61# bow. This is my primary hunting bow. Goal here was a 600-650 grain arrow with as high an FOC as I could get.

I started with the .350 spine Victory RIP XV shafts (6.4 GPI), but ran out of arrow before I could get them stiff enough. I had to wait a couple of days for a .300 spine shaft to arrive at my supplier, but soon had a batch of these stiffer shafts and was able to tune up an arrow.

Final specs for the 61# bow:
          -Victory RIP XV .300 shaft at apx. 29 ½” (these shafts run 7.0 GPI)
          -a 50 grain Easton Axis (breakoff) insert below a 100 grain brass Axis insert from 3 Rivers (150 gr total)
          -1” 1916 aluminum shaft as an external footing
          -Three 4” parabolic feathers
          -Easton Axis X nock
          -250 grain head

The completed arrow comes in at 640 grains, with a 30.3% FOC.

I also shot the same arrow with a 200 grain head. While it shows just a TAD stiff shooting through paper, I couldn’t notice a difference between bare and fletched shafts grouping on the target. It’s close enough that I can shoot either weight and be confident in performance. FOC calculation with a 200 grain head comes in at 28.4%.

[Bladepeek]

If you want to really be impressed, fletch that last one up with some little 2" delta shaped fletching. FAST and QUIET!

[dennis502]

I hear you. I think that will be the second phase of this experiment. I may play with the smaller fletching- as you said they should be a tad faster, quieter, and would result in even higher FOC numbers. All good things if I can maintain stability.

Tinkering is fun.....

[Pete McMiller]

Yes, it is fun to work up a UEFOC arrow.  The one I shoot all the time now is 660 gr. and 31.4% FOC.  Yep, fly like darts.  I currently run 3x3" fletch and the biggest reason is much less yaw in the wind.  I could likely go smaller yet but haven't so far.  

BTW:  my set up for my 60# R/D is Victory Vforce HV 300 cut to 29 5/8", 1 1/4" of 2117 footing, 100 gr. brass insert and 300 gr. target points OR Grizzly 235 gr. Kodiaks and a 75 gr. steel adapter.

[Plainsman53]

How long are the uncut shafts?

[dennis502]

Uncut shafts are 30 1/2".

[Flingblade]

What does the U in UEFOC stand for?

[Hermon]

Ultra

[Flingblade]

Thanks Hermon.  Is there a numerical designation between ultra extreme and extreme?  At what percent does it become ultra?  Not trying to hijack the thread; just looking for a clearer understanding of what is being talked about.  Thanks

[Hermon]

Flingblade, yes there is but I don't remember the numbers off the top of my head.  Go to the archive resources and read through the Ashby reports, it is in there I'm pretty sure.  Someone will probably know and chime in.

[Flingblade]

Ok, thanks again Hermon.  I have a friend that is really into the EFOC arrows but I've not yet tried them.  This summer will be a good time to do some tinkering.

[vintage archer]

There are a several categories of forward of center (FOC) used to describe the percentage of weight forward an arrow has.

    Normal FOC = 0 percent to 12 percent
    High FOC= 12 percent to 19 percent
    Extreme FOC =19 percent to 30 percent
    Ultra Extreme FOC = more than 30 percent

These designations were made by Dr. Ed Ashby for use in arrow discussion and weight comparisons. Hope this helps!  

[Doc Nock]

I've been content with EFOC and enjoyed their use.

I have friends in Western states where longer shots are taken and they resist.

I knew that Ed did research on higher EFOC having better cast, but I had to chat him up to firm my head...that is true, but only when comparing same weight arrows between normal foc and EFOC..

Getting those two types the same weight provides some special challenges, but Ed assured me it can be done.

NOrmally, a higher FOC will have more front weight and end up a heavier overall arrow.  So longer distance shooters do see more drop then with more standard FOC arrows.

Hunting back in the more dense areas I have hunted, I truly limit my shot distances.  I have had deflections when I stretched the shot in dense woods that resulted in some ugly outcomes, so I avoid that and like the heavier weight and higher FOC arrows!

AS I aged,  had to drop in draw weight, so the EFOC gives me more confidence with 50# and less draw weight to punch thru when a shot hits less then ideally.  

Some people must be much better shots to NEVER have the animal move, but I have.  EFOC ups my confidence and recovery rates!

[monterey]

Dave, you address the issue that I have in getting my woodies to high FOC. I've gotten to 23% but the arrow weight is up to 750.  Not ideal for my 44# bow!

The solution for us Woodie guys is the discovery of a wood lighter than POC and stiffer than DF.  I don't think it exists but would be thrilled to find out I'm wrong.  

[monterey]

I'll add that one thing that I've observed is that the higher the FOC, the less sensitive the setup is to spine.  That's from a very small sample observation though.

[Doc Nock]

Monty,

I guess I'm an arra ho' cause I don't care what it's made of, only that it works the way I WANT!

I fussed and fiddled with varied woods, all the stuff that went with building them and finally stumbled on carbon as a much less tedious task.

NOt knocking wood shooters, just not for me. I'd rather shoot then fuss with all the prep and finding good straight material.

I get ultra light target shafts, overfoot with aluminum, load up the front, tune bare and cut from the rear..

Emphasis on the Indian behind the bow the the arrow but do it systematically, like reloading bullets, one variable at a time...and like my results!

[Doc Nock]

duplicate...how'd that happen??  :(

[monterey]

I'd rather shoot then fuss with all the prep and finding good straight material.

I get that  

I'm a bit the other direction.  Got too much time on my hands and enjoy fiddling with stuff.  When I have an opportunity to get a new shooter started I suggest carbon or aluminum.  There's plenty of time to go backwards later.  

[Terry Green]

I can't wait to bid on the St Judes Auction!!!

[Scott Barr]

Going for UEFOC i built an arrow for my 50 @ 30" Blacktail Sitka.   Using  Carbon Express Maxima Blue Select 350s., cut at 31" with150 grain point, 11 grain insert weighted 150 grains. Total 311 grains up front. Arrow total weight is 591 grains and 25% FOC.

Paper testing indicates it flies great out of this bow. However, when I apply the Three Rivers spine calculator, it suggests that no way should this work.  Has anybody else found this to be true when building UEFOC arrows?