2nd opinion on my OT2 calcs please

Home Forums General Archery Discussion 2nd opinion on my OT2 calcs please

This topic contains 3 replies, has 2 contributors, and was last updated by 99fatboy 99fatboy 6 months ago.

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  • March 2, 2014 at 5:30 pm #621061 Back to Top REPORT
    lawrence-j-wyatt
    MT_Wyatt

    Joined: 3/27/2012
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    Can I please get a look over from some more experienced folks using this software?  I’ve done a few runs with the trial version trying to get my spine correct, as I’m planning on ordering some heavier arrows for Elk hunting.  Shooting a Helim, 65lb, 27.5″ draw, 28″ arrows (carbon to carbon).

    - I’m struggling with getting a good output.  At 65lbs, 400′s are too weak (Easton’s arrow selection charts say go with 400′s up to 66 lbs), 340′s too stiff.  I can get the 340′s right on the money if I use the brass HIT insert, slightly stiff at 50grains, 75 grains puts it right in the green.  Am I using this correctly?  If so, I need a superweight arrow to shoot 340′s/increase draw weight, or I need to turn my poundage down to shoot 400′s, without brass inserts.  FOC looks way better with the 340′s and brass inserts.

    - Not sure if I need to add the grub & monkey tails? Are these included in IBO rating? I didn’t find an answer searching for that.

    - I’m shooting Easton Flatline DOAs, 400 spine, 100 grain tips, 3 blazers, and the microlite nock –  this chrono’d at 291 fps.  (These arrows are underspined according to the software, which makes sense – without helical fletching they impact right of field points).  I read on some other posts here that I should adjust the performance factor so the calculated velocity matches what I chrono’d.  I did this and settled on -11 to generate the results below.

    - If this is ran correctly, what’s your opinion on the best combo here?  I like the weight of the FMJs, but the regular Axis 340 with the 75gr brass HIT insert seems to be the best option, retains a little more speed, and still up over 78 on KE.

    If these pics don’t expand so you can see the #’s when you click on them please let me know and I”ll insert the full size ones.  Thanks for anyone who’s willing to help, I’m trying to learn a little more before I buy arrows this time!
    -James

    FMJ_340_50g brass insert FMJ_340_75g brass insert FMJ_340_normal insert FMJ_400_normal insert Axis_340_75g brass insert

    March 2, 2014 at 5:42 pm #621063 Back to Top REPORT
    99fatboy
    99fatboy

    Age: 52
    Joined: 2/15/2010
    Location: n.y.
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    Without even looking at your charts, a few questions and comments arise. A stiff arrow is always better than weak with broad heads. I would definitely go with a 300-340 spine rating.What hunting arrow do you want to use? Flatlines aren’t really a good choice, they are too light. Fixed blades or mechanical? If you are looking for good f.o.c., you can always go 125g. on the broad head.
    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
    March 2, 2014 at 6:31 pm #621077 Back to Top REPORT
    lawrence-j-wyatt
    MT_Wyatt

    Joined: 3/27/2012
    View My Bows
    Yep that makes sense, thanks for the reply.  I have OT2 set on “hunting” which I understand to mean it gives a slightly stiffer spine as ideal.  Sounds like being even stiffer than “ideal spine” is ok, I know I’ve read that on here regarding the Helim previously.  I’m using 100gr slick trick mags, 4-blade fixed. I’d like to use the FMJ, replacing the Flatlines for just the reason you brought up – they are way too light.
    March 2, 2014 at 7:04 pm #621079 Back to Top REPORT
    99fatboy
    99fatboy

    Age: 52
    Joined: 2/15/2010
    Location: n.y.
    Photo Gallery
    Sounds like you are on the right track, the fmj in 300 or 340(whichever flies better) with a slick trick should make for deadly medicine.
    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
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