Barely Above Heavy Bone Threshold Ultra-EFOC Arrow

[Andy Cooper]

The HH Heavyweight is suppose to have a deflection of ~.205@28". That seems awfully stiff to me.  I posted a question on 3 Rivers website...hopefully they can be of assistance.

[Andy Cooper]

"I am researching a good starting place for developing an EFOC arrow weighing ~780-830 grains for a 60# ACS bow. I'd like to get as much weight up front as possible (obviously.) These bows are extremely efficient. Is the HH heavyweight too heavy for this? My draw length is 28", so I could cut some length off, if needed. Which Hammerhead shaft do you recommend as a starting point? Thanks!"

Johnathan Karch from 3Rivers Archery said:

"I would say if you are looking for EFOC that you should do just fine with the HH heavyweight carbon arrow. The arrow might be a bit stiff, so do not cut too much off at first. The standard HammerHead would be the best option if you were not going heavy point weight, but I would say if you are looking in the 200 gr + range on the front go HH Heavyweight."

[Friend]

chopx2 -- I use the planing method to get me close. I frequently end up reminding myself that I can only tune as well as I shoot. Tuning arrows with BH's in relationship to my fletched shaft is ,by far, IMO the only way that I can be confident. On several occassions I thought I had my bareshafting right on and found my BH's grouping up to 4-5"s differnt at twenty. Slight tweaks to my set-up brought the BH's and fletched shafts together. I have then shot the bareshaft, fletched shaft and the shaft with the BH and all three were w/i 2"s at 20 yards.

[chopx2]

Friend, Thanks. It was perplexing to me because another bow I had with nearly identical specs acted "normal".

Andy, the key to FOC is putting as much up front relative to how much you have in the back. It is far easier to achieve ultra extreme FOC with lighter weight but stiff spine shafts.

I am not familiar with the Hammerheads, but from what I've read they are heavy which would could drive up total weight very high if you are trying to get over 30% FOC.

slivrslingr - you could shorten the arrow (confirm first with lower point weight before cutting) or you could build out your side plate which will make the arrow act stiffer.

[Andy Cooper]

Part of the Hammerhead's weight comes from the footing they put up front, but I don't know how much is there.  Looks like I'll hafta ask Jonathan Karch @ 3 Rivers...will post when question answered.

[AKCrazyhorse]

I'm having an experience a little different from Andy's I'm finding I"m able to tune a shaft that according to all the charts should be astronomically weak.  I'm shooting a 58 @ 28 centaur.  Im only pulling about 25.5 inches and am shooting a 25.75" beman mfx trad, cut to 25.75 with a 100 grain insert, 300 grain head, cut down wrap and 3 3.5" low profile banana cuts.   FOC measures out to 28.6%.  Everything I know about arrow selection says this should be way weak. Wrong.  It flies like a dart.  Bare shafts, fletched shafts and broadheads all fly together out to 25 yards.  I'm not complaining just wondering if the effects of EFOC and UEFOC go beyond penetration considerations and perhaps may force us to re-think the effects of foc on dynamic spine reactions. Thoughts?

[Andy Cooper]

How close to center is your shelf cut? If I understand correctly, the further away from center a bow is cut, the weaker spine it needs so the arrow can progress properly through its paradox. Maybe someone who knows more than I can help!!!???? (shouldn't be too hard to find a gaggle of folks who know more than I know!!  :D  )

[Andy Cooper]

Well, scratch that idea. I just looked on Centaur's website, and they cut to center. Hmmm....do you have a built up strike plate?

[AKCrazyhorse]

I got a little moleskin on it but even that is shaved down to a bare minimum.  Not complaining now, I've got a 29% FOC arrow weighing just above the heavy bone threshold at 670 grains and it flies like a champ.  Nope, not complaining, just don't quite understand it.

[Gil]

AKCrazyhorse, You are pulling around 46-47.5# at your draw, and the short arrow length probably would just spine right for you.What size mfx are you shooting btw?With a 25.5 draw and 25.75" arrow,doesnt the broadhead touch your finger at full draw with just 1/4" clearance from the back of the riser?I sure would like to ba able to hunt out there in alaska someday,dont know if I can handle the cold though.  

[Andy Cooper]

I hadn't considered the arrow length...the shorter ya cut 'em, the stiffer they get.