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    Help Needed with Bullet Crossbow Prod

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    JacobL
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    Help Needed with Bullet Crossbow Prod

    Post by JacobL on Mon Feb 05, 2018 4:47 pm


    Here's a picture to show the spring steel I have available.

    am planning on making a bullet crossbow for shooting very light ammo such as marbles. It may or may not use a pouch design as I find that unsafe. 

    I need some help with the prod. If I'm going to be shooting stuff like marbles or clay pellets, what should I be looking for? A high or low draw weight?
    Long or short bow? Long draw length? 

    In my head, I see a tapered, skinny, 60 pound bow performing best, but I'm concerned about dryfires. My little bb crossbow handles them well with the thin prod, but I'm worried of failure at higher draw weights. 

    Also, if it helps, a marble in 0.68 cal like I am planning on using should amount to 84 grains. 

    Thanks in advance to those who can help me out here!
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    JacobL
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    Re: Help Needed with Bullet Crossbow Prod

    Post by JacobL on Mon Feb 05, 2018 4:51 pm

    Oh yeah, and if this information helps, I have tested the prod shown in the photo. Draw weight reaches past 100 pounds. Despite the worrying holes throughout, the bow still flexes evenly at the tapered ends. 

    Bastard string was pretty loose, so draw length would be hard to measure, I'm sure it would max out at 8". 

    Is this a useable candidate, or are the holes too dangerous?

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    Re: Help Needed with Bullet Crossbow Prod

    Post by 8fingers on Thu Feb 15, 2018 9:14 pm

    My rule in longbows is bow length =2.2 X draw length. So prod length divided by 2.2 should give you a good estimate  of draw length. I think a longer bow might be a better bet. In the Traditional Bowyers Bible there are several essays that show draw length/ draw weight curves that will explain it better than I can.

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    Re: Help Needed with Bullet Crossbow Prod

    Post by Crossbowmen on Fri Feb 16, 2018 1:13 am

    Hey there Jacob,
    I (tried) making a crossbow with steel prod myself. I cut out the bow from some leaf spring. It was so powerful that it did not bend the slightest. I found this video years ago of a men making the same kind of crossbow (- https://www.youtube.com/watch?v=y6h6pRQJ2_I -)
    The most important thing I lurned from my project is to keep the prod thin and not overheat it.
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    JacobL
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    Re: Help Needed with Bullet Crossbow Prod

    Post by JacobL on Sat Feb 17, 2018 2:32 pm

    Thank you for your help everybody. I think my plan is to go with a long, thin prod with a 60-90 pound draw. 1/8 of an inch thick, springs taken from an old snowmobile suspension. I'll keep doing more tests first, though.

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    Re: Help Needed with Bullet Crossbow Prod

    Post by Crossbowmen on Sat Feb 17, 2018 2:43 pm

    That sounds like it would make a great bow. A snowmobile suspension sounds like a far better leaf spring then the one from a Jeep I used. It should make a very powerful bullet crossbow.

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    Re: Help Needed with Bullet Crossbow Prod

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