Okay to be a little under spined?

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This topic contains 10 replies, has 5 contributors, and was last updated by  Ryan83Creed 1 year, 4 months ago.

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  • April 18, 2013 at 12:20 pm #574486 Back to Top REPORT

    fuegie

    Age: 33
    Joined: 4/18/2013
    Hello,

    I’m currently new here to this forum and I haven’t looked around yet if there is a topic on this and I do know what majority of the answer may be but I just want to get it out there for you guys to reply on it. I am currently shooting a z7extreme 70# 27in dl. I previously was using a 350 carbon express shaft  that weight in around 355gr but when I changed to the blue streaks model, I went with the 250′s  because I am not sure if I want to stay shooting at 70#,  but I don’t want to lower the #  any time soon yet. I am like 5 grain shy of the minimum grain for my bow, which should be 350(currently about 345) I believe and I was wondering if there are any consequences if I’m shooting just a little shy of the minimum grain weight.

    April 18, 2013 at 12:34 pm #574490 Back to Top REPORT
    bow-drawn
    Bow Drawn

    Age: 63
    Joined: 11/14/2007
    Location: Ohio
    View My Bows
    Tuning issues for one and I imagine if you work at it you could tune the 250 with a field point. If you don’t shoot broadheads, like fixed bladed one, you will be maybe okay. You also run to potential for the arrow shaft to break running it under weight and under spined and that might cause injury to you.

    To me I see no rational reason to use the 250 model. There is a reason they make a selection of different spine sizes. JMHO

    April 18, 2013 at 12:51 pm #574491 Back to Top REPORT

    fuegie

    Age: 33
    Joined: 4/18/2013
    When I first bought my arrows, I was set at about 63#  and with me shooting 350 shafts, I was a little over spined,  although being over is better for kinetic energy and for the bow. I wanted to buy the 250  to make sure that I was correctly spined  but I eventually worked my way up to max dw at 70# now so I can get the most out of my bow at max performance. I can just lower my poundage down to 68#  just to make sure I’m within my minimum spine but I’d prefer leave it at 70#  if I had my choice since I’m only like 5gr under.
    April 18, 2013 at 4:15 pm #574503 Back to Top REPORT
    bow-drawn
    Bow Drawn

    Age: 63
    Joined: 11/14/2007
    Location: Ohio
    View My Bows
    I forgot to welcome you in my first post. Welcome.

    The full story makes more sense to me now. And sounds like you have a better understanding of what you were asking in the first post. It’s all about being accurate and how to achieve it and have fun doing it.

    April 18, 2013 at 4:25 pm #574504 Back to Top REPORT
    99fatboy
    99fatboy

    Age: 52
    Joined: 2/15/2010
    Location: n.y.
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    just want you to realize that arrow weight has nothing to do with spine. even if you lower poundage, the 250′s will be to the weak side of optimal spine rating. grains of arrow per pound of draw weight and arrow stiffness are two different subjects, both of which are important to know.
    black z7 magnum,tommy hogg,qad,b-stingers, vaportrail: blue smoke triumph,sword,hamskae,b-stingers:desert tactical chill R, tommy hogg,limbdriver pro v,ktech
    April 18, 2013 at 8:43 pm #574545 Back to Top REPORT

    fuegie

    Age: 33
    Joined: 4/18/2013
    Okay, thanks guys for the help. Yeah, 99fatboy, I meant to say weight wise but accidentally said spine. From what I can recall from carbon express spine chart, a 27in DL at 69# DW is a 250 spine, but since I’m set at 70#, they recommend the 350 spine. Like I said, the only reason why I don’t want to lower my poundage is because I have no issue drawing it and I want the most out of my bow but i really need to be at the 69# for the 250 shaft. That’s why I’m here just needing some reassurance that I should still be okay with the 70#, but if I’m not getting any reassuring answers then maybe I might need to turn it back down a pound or two just to make sure that everything will be fine.
    April 18, 2013 at 8:52 pm #574546 Back to Top REPORT

    fuegie

    Age: 33
    Joined: 4/18/2013
    Okay, thanks guys for the help. Yeah, 99fatboy, I meant to say weight wise but accidentally said spine. From what I can recall from carbon express spine chart, a 27in DL at 69# DW is a 250 shaft, but since I’m set at 70#, they recommend the 350 shaft. Like I said, the only reason why I don’t want to lower my poundage is because I have no issue drawing it and I want the most out of my bow but i really need to be at the 69# for the 250 shaft. That’s why I’m here just needing some reassurance that I should still be okay with the 70#, but if I’m not getting any reassuring answers then maybe I might need to turn it back down a pound or two just to make sure that everything will be fine.
    April 19, 2013 at 10:29 am #574584 Back to Top REPORT
    bow-drawn
    Bow Drawn

    Age: 63
    Joined: 11/14/2007
    Location: Ohio
    View My Bows

    Okay, thanks guys for the help. Yeah, 99fatboy, I meant to say weight wise but accidentally said spine. From what I can recall from carbon express spine chart, a 27in DL at 69# DW is a 250 shaft, but since I’m set at 70#, they recommend the 350 shaft. Like I said, the only reason why I don’t want to lower my poundage is because I have no issue drawing it and I want the most out of my bow but i really need to be at the 69# for the 250 shaft. That’s why I’m here just needing some reassurance that I should still be okay with the 70#, but if I’m not getting any reassuring answers then maybe I might need to turn it back down a pound or two just to make sure that everything will be fine.

    If you take the time and do the two I copied below you’ll see you are a 350 model and not a 250. Like a said above I don’t see why you would want to hunt with the 250 unless your stats are much less than what you are posting. I bet if I ran your numbers on OT2 software you are a .340 or stiffer spine for a proper arrow. 

    CE BOW DRAW WEIGHT ADJUSTMENT
    CE Hunting Arrows selection chart

    April 19, 2013 at 11:03 am #574596 Back to Top REPORT
    gjarcher
    gjarcher

    Age: 71
    Joined: 10/3/2006
    Location: Colorado
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    …  I am like 5 grain shy of the minimum grain for my bow, which should be 350(currently about 345) I believe and I was wondering if there are any consequences if I’m shooting just a little shy of the minimum grain weight.

    Yes, there are a few things to consider:
    - Warranty does not cover damage caused by shooting underweight arrows. Should something happen, you are at your dealer’s and Mathews’ good graces, and no firm ground for complaint.

     

    - Safety. This has nothing to do about warranty or arrow spine, but rather your personal “comfort zone” regarding injury due to bow failure, such as broken riser or limbs. The safety ‘margin’ adopted by the Archery Trade Organization is on the conservative side, and based on not only peak draw weight but also cam efficiency, draw length, and Brace Height (powerstroke length), which is assumed to be 7″ on this chart for a Speed Cam. A less conservative approach to personal safety, lower brace heights, etc. requires some interpolation of this chart, but it should be done with an informed mind. {#emotions_dlg.mathews_peace}
    AMO_minArrowWt

    Competition rules. If you shoot IBO 3-D, you would be disqualified with arrows weighing less than 5 gr/lb of peak draw weight, unless the arrows chronograph less than 280 fps. If you shoot ASA 3-D competition, you would be disqualified if the arrows chronograph faster than 280 fps + 3% (288 fps).

    - Arrow integrity. Always check arrows before shooting them. Weak spined, thin-walled shafts are more prone to cracks and failures. They should be checked rigorously and even then, accidents like this might not be avoidable … caused lower limb splinter, cam bent, broken sight fiber optics, and the only good news was the golf-ball sized lump on my wrist went away in a week.

    VX22_failed 001

     

    - Bowhunting. Weak spined arrows, even with fixed-blade broadheads, can shoot very accurately IF one’s form is extremely consistent. Unfortunately, cold weather, bad weather, awkward shooting positions, heavy camo clothing, face masks, etc. work against shot consistency. Practicing the way you will actually hunt is a good way to learn personal limitations.  Getting broadheads and field points to have the same Point of Impact (POI) is unlikely with weak spined arrows, especially with fixed-blades, so it is best to just make sight settings for the type of point being shot. The more an arrow flexs when launched, the less likely different types of heads will have the same POI due to differing aerodynamic forces acting on them, and the greater flex of the arrow also occurs on impact, so a good percentage of the penetration potential is lost, especially on bone. Before hunting with lightweight arrows, I recommend they actually be tested and studied for penetration potential rather than depending on anecdotal information, like “speed kills”. Weak spined arrows usually have thinner wall thickness and are more prone to fail holding the broadhead and insert in place on impact, often banana-pealing, and ruining any penetration. Also, broadhead integrity is more important with weak spined arrows because if the broadhead ferrule or blades bend causing deflection of the penetration path, the added torque on the shaft will cause it to break, usually about 3″ to 4″ back from the broadhead. The worst possible feeling is to watch your first successful bow shot run off with the arrow sticking out of it, only to find the broken shaft and the end of the blood trail 50 yds away and no game to recover, and days of agonizing searching and revisiting what went wrong in your mind.

     

    Thin-wall shaft and broadhead failures:
    BH_Shaft failure 001

    Stinger_ElkScapula1a

    Elk

    … just some food for thought, hope it helps. {#emotions_dlg.mathews_peace}

    • This reply was modified 1 year, 4 months ago by gjarcher gjarcher.
    April 19, 2013 at 1:41 pm #574621 Back to Top REPORT

    fuegie

    Age: 33
    Joined: 4/18/2013
    Thanks gjarcher for such in depth information, I greatly appreciate it. I guess I have made up my mind that I’ll try to sell it to one of my relatives/ friends first to see if anyone if them need new arrows so I can buy the correct shaft/spine for my setup. We’ll see what happends and like I mentioned on my other post,I may just have to lower my poundage back down to at least the mininum requirement just to be on the safe side if im not able to get rid of it.
    April 20, 2013 at 9:19 am #574700 Back to Top REPORT

    Ryan83Creed

    Joined: 4/14/2013
    Location: Minnesota
    View My Bows
    Yeah that’s some nice info a pics! Thanks Gjarcher!! That’s some good stuff.
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