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On a hunting head a idea ZONE so to speak is 12 - 14% depends on which book you might be reading...most claim 12%. On the other hand as long as you did not get it so heavy it fell off your crossbow it would work, might only get 3fps and shoot 3ft but yer group would be tight....
This is what I have read and found in my searches on FOC. I want too tell ya their is a lot on FOC out there Test and see is the tried and true method that works fer most...My hunting bolts are in the 11% FOC and group good for me out to 40yards, I will only take a 30 - 35 yard shot and most have been at 20 - 25 yards on deer.
I have seen in action and also have read where the FOC is most important on lighter carbon arrows that were grouping good at say 20 yards and started opening up at 30 yards and futher.
When I was shooting longbows and recurves, I never bothered with FOC. I found that if spine was near perfect FOC would take care of itself. Interesting to note that the FOC usually always came out to very near 10%, plus or minus 1/2 point.
With my compound bows, I really like the little 75 and 100 grain heads. I use 26 inch arrows, 28 inch draw, 2 inch overdraw. FOC usually comes out to 7 1/2-8 1/2%. I can usually sho0t spots with these up to 40 yards.
The crossbow bolts I make run from a low of 9.4% to a high of 10.8%. The ones I am making for my new Vixen come out to 10.8% and I expect great thing for them.
If you are shooting really long range 3D or targets, a lower FOC will give you a better trajectory curve. I can't draw diagrams here, but, the lower FOC you can get away with the better that curve. That is important if you are shooting 30 to 100 yard targets.
If you are hunting, more FOC will help the tail of the arrow stay at the tail and track the head. However, it will cause your trajectory curve to be steeper and have a steeper drop at your extreme, maximum range. If your max range was, say, 40 yards and your launch speed was 250 fps or more, this would not be of any concern. The increased accuracy POTENTIAL would be more important.
I used to demonstrate this by shooting my little 42 pound compound with my 75 grain heads and 3.5 inch fletch. I could shoot spots at 30 yards with no problems. I would then switch to a bare shaft with 160 grain field points and shoot spots out to 30 yards. Not as accurte as the fletched shafts but enough to demonstrate the point. 3 inch at 30 yards with the bare shafts were common.
I don't factually know if there is such a thing as to much FOC in reality. I have never reached that point. I feel there is such a thing as to much FOC factually, but, you would have to really come up with an unusual bolt, fletch, head combination to reach that point in a hunting application. I doubt it would ever happen.
Beaver very good read and very good information on FOC. For most of my shooting with field tips mine cal. out at 9 - 10% FOC with Lazer II's 4" feathers and 100gr heads, the SlickTricks in 100gr with my Brass inserts cal. @ 13% with 4" feathers.
Some of my writting on FOC was taken from writtings by Bob Robb from: Bow Masters, Spring 1999 and stated W/F and lightweight Carbon Arrows one could tighten ones groups at longerdistances.
At the ranges most of us shoot crossbows (Hunting) FOC may not be a critical condition involving erratic bolt flight. Again I will quote from my material "The Importance of Weight Forward Balance" the following:
As champion 3-D and indoor tournament shooter Randy Ulmer, who is also one heck of a (BOW HUNTER) is fond of saying " I'd rather have a slow hit than a fast miss any day."
I have learned more from Bob Ragsdale and Randy Ulmer than all other sources combined. It was Randy Ulmer that convinced me to drop the draw length on all of my compounds by 1/2 inch and use a string loop. That was the most dramatic contribution to accuracy that I ever experienced with the compounds.
I hope I can get my new Vixen to shoot with repeatibility and accuracy. I am so used to having unlimited adjustability with compounds that I am going to feel lost with the crossbow.
I have helped many others set up crossbows(such as it is) and have had no tune problems to speak of. They either work or they don't. My somewhat limited experience with the crossbow indicates that they may be a little more sensitive to total bolt weight, a smaller weight range that they like best. I have one compound left that will give excellent accuracy with arrows from 320 to 425 grains.
I recently helped a fiend set up a TenPoint Titan and we went through 12 different bolt, head weight, fletch combinations before we found one it especially liked. Once we found the correct combination, it gave exceptional accuracy, on the order of 3 inches at 40 yards. That was a 20 inch 2219 bolt, 5 inch right offset feathers, 125 grain tip.
I have made up some 2216's to try with my Vixen when it arrives. I am trying 5 inch feathers, 4 inch feathers, and 4.75 inch vanes, all right offset. I have 100 and 125 grain field tips and heads. i think I will also try some heavy 2219's with 5 inch feathers and 125 grain heads.
Gary I went back and was reading my entry and answers ect I realized I may of offended ....I didnt mean to insinuate that you couldnt understand my simple question...sorry friend I didnt mean it like that I just wasnt for sure I was explaining myself good enough..I know you will say no big deal, but I wanted you to know I caught it and wanted to fix it..
The instructions you guys explained were great, just thought I would throw this into the mix!
This method may not be as accurate as using actual weight, but I am sure it would work for a quick refference!
Last edited by BUCKSHOT on Sun Mar 06, 2005 7:58 am, edited 1 time in total.
I have helped many others set up crossbows(such as it is) and have had no tune problems to speak of. They either work or they don't. My somewhat limited experience with the crossbow indicates that they may be a little more sensitive to total bolt weight, a smaller weight range that they like best. I have one compound left that will give excellent accuracy with arrows from 320 to 425 grains.
I would have to respectfully disagree on the "sensitivity" of crossbows in relation to VARYING arrow weights. My S.M. Vixen shoots my 333 gr. GT Laser II's as accurate as my 425 gr.+ 2219's.
I think it is more of a function of the fact that Excal's use a simple, yet consistent recurve limb design vs. compounds with wheels/cams, etc..
What really amazed me is the ability of my crossbow to have an appetite for such a wide range of weights and spines as far as arrow selection is concerned.
Whatever arrow/BH combination you shoot.......DO NOT SHOOT AT THE SAME SPOT MORE THAN ONCE!!!!
I am very pleased to hear of the weight range. As I said, my experience is very limited.
I have my own little hobby, non commercial bow shop. I have a mechanical bow press, a hydraulic bow press, equipment for setting centershot, cam sync, and about anything a well equipped archery pro shop would have.
The most common crossbows around my part of the world are sold under the PSE brand name. They are made by Horton and TenPoint. The next most common(and fastest growing) is the Parker brand as the Parker facility is just up the road in Mint Springs. I got to shoot an older model Vixen when I made some bolts for its owner. I don't know exactly what year it was but I believe it was about a 2000 model. I was extremely impressed by that bow, so much so that I now have one on order.
I hunted with a recurve from 1954 to 1989. In 1991, after a serious injury in 1989, I started to use a compound and used one through this season. I was so impressed by the crossbows that I set up for other folk that I decided to get one for myself. I have some 2213, 2215, 2216, and 2219 shafts. I have 3.875 vanes, 4.75 vanes, 4 inch shield, 4 inch parabolic, and 5 inch shield cut freathers. I have 75, 85, 100, and 125 field tips. I am going to make an endless loop jig and a flemixh jig for the short strings. Hopefully, I will come up with a combination that will give me the 1 inch per each ten yards archers minute of angle. It is certainly going to be fun trying :^)
Beaver please keep us posted on any results you get. Reads as you can do what ever has to be done. You should find that the 2213's fly nice from the Vixen and the 2216's make a very good hunting bolt. Of course Lazer II's are the best of two worlds.
Test and see is the tried and true method that works fer most...My hunting bolts are in the 11% FOC and group good for me out to 40yards, I will only take a 30 - 35 yard shot and most have been at 20 - 25 yards on deer. 
