Full-auto crossbow

This is a very nifty invention.

The inventor seems to have used a magazine and bolt design similar to the ancient Chinese repeating crossbows.

From the inventors website

The specification I devised called for a full auto-firing rate of 1 bolt per second; with 6″ of draw length and a minimum of 30lbs draw weight. The magazine was to house 10 bolts 9″ long. The bow was to be capable of discharging the full magazine with imperceptible slowing down and have an effective range of 25 yards.

The draw length is limited by the throw of the crank that pulls the bow carriage plus the relationship this has with the near stall torque that can be pulled out of the motor / gearbox assy. The need to maximise these relationships must be balanced against the voltage / number of batteries / weight.

The above was achieved using 8 AA rechargeable NiCd batteries giving 9v.

Hat Tip: SaysUncle and egosumquisum

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • subby

    Can’t believe the guy made this run on batteries. The chinese didn’t have batteries, isn’t that cheating?

  • dogon1013

    Very cool.

    How much, and when will they be available.

    He needs to slap some Lithium batteries in there and up the BPM’s (Bolts per minute)

    Is it correct to call this an “invention” since the repeating crossbow was allready invented thousands of years ago, this is just a motorized repeating crossbow. I guess it’s more of a modernization of an invention. Granted, the mechanism to motorize it had to be invented.

  • SpudGun

    I loves me some mad inventors and this guy fits the bill perfectly. Well done sir!

    Believe it or not, in medeval times this rate of fire would have been quite slow for a castle defending cross bowman. The latest research indicates that for every shooter, there were four crossbows and loaders. The bowman would fire, chuck the empty crossbow to a loader and immediately grab another already cocked and locked.

    Still, if the zombie apocalyse is replaced by the vampire swarm, this device would be ideal.

  • AJ187


  • Peter

    Oh no – someone has let poppa smurf loose in the armoury again!

    But seriously, thats a clever piece of kit – as long as speed shooting isn’t a requirement. Now if you could reduce the bulk, that would be seriously cool.

  • Carl

    Like most battery-powered devices it seems rather weak and low in endurance. Put a weed-wacker engine on that thing to reach the full potential.

    Here’s hoping the UK authorities don’t find out about this guy as I’m sure they would love to raid him like they would a nuclear terrorist.

  • Brad


  • Good post.

  • Pretty cool. But it’s way too loud for hunting.

  • justim

    the top portion looks like a dulcimer with a scope!

  • exhunter223

    Very nice…. I WANT ONE

  • Player_L

    Got a couple ideas for the Mark II version: First, lose the electric engine, and get a 2 stroke 50cc chainsaw engine. Rate of Fire and Awesomness will go way up!
    Second, you should make a drum magazine, or just adapt a soviet AK-47 75 shot drum by removing the covers.(they are cheap, and simple indeed).
    Now, THAT would be a weapon ancient chinese would be proud of!!

  • Weed wacker’s are known as different names. Although it is different named but it’s capabilities are same.It may different from each other but it is not a large difference among them. Actually it has a great significant on removing the grasses. Thanks for your article.