Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: arrow spine/FOC...does it matter

  1. #1
    Senior Member HawgEnvy's Avatar
    Join Date
    Feb 2011
    Location
    Ionia(I-OWN-YA)Mi a prison town,go figure
    Posts
    1,463
    Post Thanks / Like

    Default arrow spine/FOC...does it matter

    is it something I should worry about or is it over-rated? I shoot 3D for hunting practice only and only hunt deer and small game. both bows in my sig have 60# limbs,28.5" draw. I'm shooting 400 spine arrows. I can go as short as 27". I've got tight groups as it is w both 100 and 125gr heads w Blazer vanes.

    also,is being over-spined an issue. I know under-spined will cause erratic arrow flight.
    '14 ChillR 28.5"/74# Extreme Recon sight,Schaffer Opposition rest,LS modular stab, Beman ICS Hunter 340

  2. #2
    String builder/ Super Moderator Hutch~n~Son Archery's Avatar
    Join Date
    Aug 2009
    Location
    Gilmanton, New Hampshire
    Posts
    5,755
    Post Thanks / Like

    Default

    Quote Originally Posted by HawgEnvy View Post
    is it something I should worry about or is it over-rated? I shoot 3D for hunting practice only and only hunt deer and small game. both bows in my sig have 60# limbs,28.5" draw. I'm shooting 400 spine arrows. I can go as short as 27". I've got tight groups as it is w both 100 and 125gr heads w Blazer vanes.

    also,is being over-spined an issue. I know under-spined will cause erratic arrow flight.
    First, over spined is not an issue. But under spined is like a dry fire. That's if it is too under spined. FOC is not that much of an issue if you are a target shooter. As for a hunter it is a good thing to be close or above the % recommended. This is for penetration and flight.

    HUTCH
    Bow String Depot Custom String Builders
    Need a string set pm or email me @ bowstringdepot@gmail.com
    or check us out @ http://bowstringdepot.com

  3. #3
    Senior Member NuttyNative's Avatar
    Join Date
    Feb 2011
    Location
    Fernley Nevada
    Posts
    587
    Post Thanks / Like

    Default

    Quote Originally Posted by Hutch~n~Son Archery View Post
    As for a hunter it is a good thing to be close or above the % recommended. This is for penetration and flight.

    HUTCH
    Not to hijack here, what is FOC? And why is it a good thing for hunting? What's the formula to find it?
    I'm a Lefty


    2011 Martin Ridge Hunter
    2012 Rytera Alien Z
    2008 Diamond Marquis
    2008 Diamond Marquis
    2009 Bowtech Sentinel
    2009 Bowtech Sentinel

  4. #4
    Senior Member
    Join Date
    Jan 2011
    Location
    SW OK
    Posts
    1,480
    Post Thanks / Like

    Default

    Forward Of Center of the arrow. Basically it needs to balance right to fly right. Check out the link near the bottom of the page.

    http://www.huntersfriend.com/carbon_..._chapter_4.htm
    Firecat 400

  5. #5
    Senior Member HawgEnvy's Avatar
    Join Date
    Feb 2011
    Location
    Ionia(I-OWN-YA)Mi a prison town,go figure
    Posts
    1,463
    Post Thanks / Like

    Default

    FOC=Front of Center. It the balance point of the arrow with the broadhead/field point attached. Not exactly sure of the formula, but here goes. If I'm wrong,someone correct me. Find the balance point of the arrow by placing it on a sharp edge. Imagine your arrow balancing on a triangle. Mark the balance point. Insert the broadhead/FP then do it again. Since weight has been added to the front of the arrow, the balance point is now Front of Center(mark location,measure) To find the balance point,measure the arrow and divide it by 2.(ex.28"arrow divided by 2=14"center) that will give a ballpark figure. It may or may not be exact depending on your particular arrow(vanes,dipped,nocks,etc). If your balance point w BH is 12" from the end and the balance point w/o is 14", take 12 and divide by 14. It comes to .857(8%). IIRC,7-10% FOC is what we're going for.

    like I said though, I could be wrong on this whole thing. It's new to me also. Hopefully the real pros will chime in.
    '14 ChillR 28.5"/74# Extreme Recon sight,Schaffer Opposition rest,LS modular stab, Beman ICS Hunter 340

  6. #6
    Senior Member NuttyNative's Avatar
    Join Date
    Feb 2011
    Location
    Fernley Nevada
    Posts
    587
    Post Thanks / Like

    Default

    Quote Originally Posted by MLN1963 View Post
    Forward Of Center of the arrow. Basically it needs to balance right to fly right. Check out the link near the bottom of the page.

    http://www.huntersfriend.com/carbon_..._chapter_4.htm
    Excellent info, thanks a bunch. According to their chart with 100 gr tips I'm at 11.7% and with 125 it goes to 13.8%.
    I'm a Lefty


    2011 Martin Ridge Hunter
    2012 Rytera Alien Z
    2008 Diamond Marquis
    2008 Diamond Marquis
    2009 Bowtech Sentinel
    2009 Bowtech Sentinel

  7. #7
    String builder/ Super Moderator Hutch~n~Son Archery's Avatar
    Join Date
    Aug 2009
    Location
    Gilmanton, New Hampshire
    Posts
    5,755
    Post Thanks / Like

    Default

    Maybe this can help. Take a simple dart used in a dart game. Okay most of the weight of the dart, is to the front of the body. When thrown the weight is what pulls the dart to its destination. If you lessened the weight, the dart would fly erratically. Reason the weight of the rear would almost equal the front. Thus the rear would catch up to the front and the dart has no stability. The arrow is the same principle. The weight needs to be closer to the front, in order to keep the arrow on the correct path.

    Hutch
    Bow String Depot Custom String Builders
    Need a string set pm or email me @ bowstringdepot@gmail.com
    or check us out @ http://bowstringdepot.com

  8. #8
    SonnyThomas
    Guest

    Default arrow spine/FOC...does it matter

    So many arrows on the market, you have to look at the quality or I should say the make up of the arrow as weight is not a true indicator, such as Carbon Express's Rebels. Other arrows can have incredible spine, but can be to light, such as High Country's Pro Max.

    Offhand, your set up with 400 spine arrows should be well and good. This would especially be true if your bow is launching the arrow true and spine checked and fletched your arrows according. Cutting your arrows shorter than 28" is probably unnecessary. I might have concern with the 125 gr heads, but good accuracy and good grouping is the real indicator here.

    Hunting wise, I don't care for arrows going below 350 grs, but then I know some who have lighter arrows and get the job done. I'd say good arrow placement is helping get the job done.

  9. #9
    Senior Member NuttyNative's Avatar
    Join Date
    Feb 2011
    Location
    Fernley Nevada
    Posts
    587
    Post Thanks / Like

    Default

    I shoot the 340 Easton Axis nano tubes. 29.5" and a total weight of 430gr using 100 gr tips. Bow is at 68 pounds.
    I'm a Lefty


    2011 Martin Ridge Hunter
    2012 Rytera Alien Z
    2008 Diamond Marquis
    2008 Diamond Marquis
    2009 Bowtech Sentinel
    2009 Bowtech Sentinel

  10. #10
    Senior Member HawgEnvy's Avatar
    Join Date
    Feb 2011
    Location
    Ionia(I-OWN-YA)Mi a prison town,go figure
    Posts
    1,463
    Post Thanks / Like

    Default

    I ordered some arrows from Harvest Time Archery. They're 400 spine. I think I'm going to stick w 100gr heads. They should be here tomorrow so I can get a feel for them. Has anyone else shot these?
    '14 ChillR 28.5"/74# Extreme Recon sight,Schaffer Opposition rest,LS modular stab, Beman ICS Hunter 340

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •