arrow weight explanations?

Discussion in 'General Archery Forum' started by n2t, Feb 19, 2007.

  1. n2t

    n2t Senior Member

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    Right now I'm shooting between 55-60lbs pull on my bow and getting around 226fps with my arrows. I'm shooting GT hunter expeditions at 8.2 grains per inch. When I go on the calculator no matter if I raise my tip weight, draw weight or what I do I seem to get the best KE with this weight arrow. Anywhere from 50-75 lbs of pull 8.2gpi is giving me the best numbers. I've read that heavier arrows penetrate better, but can't seem to prove this out with the KE numbers. I'm shooting 5575s right now, is there a better arrow combination or is the 8.2gpi going to be my magic number.

    Also my GF is shooting the jazz arrows, and some easton nugent arrows and getting around 175-185fps and around 22ftlbs of KE. I have no idea what the grains per inch of the jazz arrows are but if anyone knows and or could make a better recomendation than those or the nuges for her 50lbs pull and 24" dl I would be thankfull. I don't quite understand all these numbers and the easton bow charts are kinda hard to figure out. Thanks to any and all who may be able to assist me in this.
     
  2. Alex

    Alex Member

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    I shoot a switchback xt and get 235 fps with only 47 pound draw weight so idk what you are doing . and while we are on the topic how durable are the cxl 2 arrows that weigh 6.2 gpi and do they drift much?
     

  3. n2t

    n2t Senior Member

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    DL seems to play a much bigger part in speed than weight from what I can find. My DL is 26.5 you must be in the 28-29" range from those speeds.
     
  4. Alex

    Alex Member

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    my DL is only 26... the only thing i have on my string is the d loop and my peep sight.
     
  5. n2t

    n2t Senior Member

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    Idk I don't think I'm doing anything. I doubt that anything during my shooting process is going to up my arrow speed. I would assume that it's a combination of your bow's efficiency (if you're working near your bow's peak weight), your higher IBO speed, arrow weight and possably cam efficiency. Heck the chrony at my bows range could be off, or the scale. Lol it's not like I'm holding the string with a 3rd hand to slow it down....
     
  6. BowhuntnHoosier

    BowhuntnHoosier Bisquit.......

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    Need to know how long your arrows are and what vanes and size tips you are shooting. So we can get the weight of your arrows. The formula is speedXspeedXarrow weight/450240=KE.

    My arrows are 29.5" long at 8.6gr per inch. I shoot blazer vanes with 100gr tips. Which makes my arrow weigh right around 394gr total with insert and nock. My arrows chrono at 276fps so I take 276X276X390/450240=65.98lbs of KE. Now if I shoot my 650gr aluminum arrows they chrono at 225fps so 225X225X650/450240=73.08lbs of KE.

    For your GF I do not know what size Jazz arrows she is shooting but you may look into Carbon Force arrows the Desparado carbon youth arrows look nice for bows of 50" peak weight. 6.3gpi. These arrows at 24" 3 blazer vanes 75gr tip and nock and insert weigh around 275gr. So at 50# DW you would not want to go below 250gr.

    I hope this helps you out and does not confuse you.
     
  7. n2t

    n2t Senior Member

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    Not that confusing I've been using a KE calculator for quite a bit. My arrows way about 350grns each. 8.2gpi, 100grn tip, blazers and 26.5" long. The one thing that does confuse me about KE is that it seems a 351grn arrow always has the highest KE no matter the speed or DL or anything else. My Bow shooting anywhere from 45-75lbs always has the highest KE with a 351grn arrow. Right now I'm getting almost 40 ft lbs of KE, so that puts me OK for deer.
     
  8. BowhuntnHoosier

    BowhuntnHoosier Bisquit.......

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    A heavier arrow will lose speed but it gains KE so what you need to do is find an arrow that gives you the best of both worlds. If your arrows weigh 350gr do not go over 70# DW you need to stay above 5grains per pound of pull. If you notice in my arrows my 650gr arrow only shoots 225fps but gained only 8# of KE. So I opted to go with my lighter arrows which went 276fps with 8# less KE.
     
  9. bullspotter

    bullspotter Senior Member

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    a 351 grain arrow will not make the same KE at 240 fps as it dose at 300, id recheck your KE calculator.... and a heavy arrow will not always make more KE then a light one, it depends on speed. Ex I did alot of resurch on my 300 ultramag shells for reloading, The Stats i had showed a higher KE with a 165 grain bullet loaded at max, then a 180 bullet did at max. It was due to the large velocity increase, but as the bullet slowed down, it lost KE faster, and at a certain distance the 180 gr bullett retained a better KE. KE is a formula of weight and speed, dosnt matter what your DL or Draw weight is...
     
  10. n2t

    n2t Senior Member

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    I was saying that with the KE calculator I found, 351grn arrows showed the highest initial KE for my bow anywhere from 45-75lbs of draw weight, which really means arrow speed but I can't predict that so I changed the weight and allowed the calculator to calculate speed. Draw weight changes speed so it does affect KE, in that way. Idk I changed the arrow weight from 350-352 and it dropped 1 grain above or below 351grns. Not sure why just what I found.
     
  11. bullspotter

    bullspotter Senior Member

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    I would check you calc then....... look at this, 351 gr arrow at 226 fps makes a KE of 39.81 and a 355 grain arrow at the same speed is 40.27...... now we only added 4 grains, I dont think your going to loose that much speed with a increase of only 4 grains. You need to know the TRUE speed and weight of your arrow. I dont think that a 351 grain arrow will ALWAYS give optinum KE. And im not real sure that a calc would give a accurate speed of your arrow, just based on arrow weight and Draw weight and DL. Theirs lots of variables that would need to be added. Also to make things worse, This KE were trying to get is pry when the arrow IS 1 or 2 feet out of the bow, So to find the KE at 20 or 30 yards, you need to know the speed at 20 or 30 yards. and im willing to bet it will be ALOT less at 30 if your starting at 226. Im not rying to erk you or get on your case about this, but i think your info is not right. and am trying to help.
     
  12. BUNNYMAN

    BUNNYMAN I pray for you!

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    I am learning alot here that I did not know prior..... so thank you for helping him.....and look no smilies so I am being serious
     
  13. bullspotter

    bullspotter Senior Member

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    Your being serious?? umm you Feeling ok?? lol NA im trying to help him out, Hope i am and not making things worse...... One way or anouther will git it figured out form him i hope.
     
  14. BUNNYMAN

    BUNNYMAN I pray for you!

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    me too....

    ok so here is my setup....

    switcback
    27" 64lbs 260fps
    maxima 250's 29" not sure of the weight....(100gr tips three aae plastifletch)

    whats my KE????:noidea:
     
  15. bullspotter

    bullspotter Senior Member

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    need the weight of the arrow.... we can get close if you know the grain per inch of the arrow, might have it right on the shaft, or we can find it on the net.
     
  16. bullspotter

    bullspotter Senior Member

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    looks like their 7.3, i have the cexprees web on my fave list BRB
     
  17. BUNNYMAN

    BUNNYMAN I pray for you!

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    sweet let me know...I have never even tried to figure this out.....
     
  18. bullspotter

    bullspotter Senior Member

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    7.3 x 29 is 211.7, + 100 for tip is 311, then figure 20 to 30 for vanes, insert, nock, depends on what you have for sure, best way it to just weigh the arrow if you can.. so we have about 341 gr arrow... or so. at 260 fps.....
    260x 260x341=23051600 div by 450240 =KE at 51.19.... will be more or less depending on your accual arrow weight..... O by the way that formula is the one Bowhuntnhoosier posted on here.....
     
  19. BUNNYMAN

    BUNNYMAN I pray for you!

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    so I need to chrono the bow again and check the actual weight of the arrow???I will do and then I can check it again.....
     
  20. n2t

    n2t Senior Member

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    Lol you're helping alot, but I'm just plugging in numbers. My total arrow weight is around 350 or so. I'm putting out around 40ft lbs of energy. Seems ok for deer hunting still seems odd that I can't get a bit more fps out of this thing. I should probably have my draw weight, length, and arrow speed checked by a second source just to be sure however, it may just be that I'm getting bad info on one or more of these items as well.