# 100 joules



## ARB (Dec 31, 2009)

Did some shooting over the chrony recently,slingshot is a big metal starship with approx 23 inch extension and Silver Thera tubing. Results were:

650 grain ammo - 45 ft/lbs
1250 grain ammo - 67 ft/lbs
1700 grain ammo - 76 ft/lbs or 103 joules

Shows the sort of KE that can be gained from using fork extensions, heavy draw rubber and the effect of huge ammo. Perhaps flat bands would have been better but I find it much easier to work with tubes and the Silver thera tubes are also very long lasting.

The monster 1700 grain lead balls are quite slow, 142 fps. Still the KE, speed and projectile weight are similar to those of a medieval Warbow. I think they're also similar to those of a pitched baseball! Obviously the arrow is a lot more lethal than the others due to being a sharp point rather than a blunt ball!


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## yeeharr (May 26, 2010)

Any pictures?


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## Pulse (Jun 16, 2010)

Is anyone else thinking "SHOOT SOME FRUIT!!!!!!!" ?


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## ARB (Dec 31, 2009)

Pulse said:


> Is anyone else thinking "SHOOT SOME FRUIT!!!!!!!" ?


I don't have any fruit videos but here are a couple of short clips shooting Coke cans filled with water.
http://slingshotforu...led-with-water/

The energy of these shots was around 95 joules. In the first video 3 cans were shredded, the ball went through them as if they weren't there. In the 2nd video only the first can was shredded, the ball impacted very near the top of the can tearing the top off it but deflecting enough to miss the rest of the cans.


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## Pulse (Jun 16, 2010)

ah ha!

if you could match this 



 with a slingshot....you may become a god on this forum...


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## JoergS (Dec 17, 2009)

Very good! 23 inches of an extension is impressive indeed. Does the accuracy suffer?

How long are your tubes in unstretched condition, and how long is your total draw with that setup?

Regards

Jörg


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## ARB (Dec 31, 2009)

JoergS said:


> Very good! 23 inches of an extension is impressive indeed. Does the accuracy suffer?
> 
> How long are your tubes in unstretched condition, and how long is your total draw with that setup?
> 
> ...


Accuracy is good, the "barrel" of the fork extension seems to help with aiming, the weight and size of the slingshot also help with stability. Obviously a wrist brace is essential with a big starship

I have become so used to it that I don't like shooting a non extended or light slingshot now or any small slingshot with narrow forks. The Barnett Cobra that I used to think was a decent commercial slingshot feels like a cheap flimsy toy for a toddler.

As for the draw length it's been a while since I measured it but I think it is 23 + 30 = 53 inches and at rest the tubes are around 11 inches, Can get accurate figures later. I find that a smooth fast draw and instantaneous release gives more power. Also as you can see from the figures I am not stretching the rubber to its limit. WIth a half butterfly draw you could probably get similar or better figures from a non extended, non braced slingshot. If you use flat bands and an over the top attachment ( I use clamp on) maybe you can break your own 130 joule record but with a handheld slingshot! You will need to use monster balls though. Maybe 2000+ grains. Jeff Tanner in the UK could make you a nice mould for them.

I think it really shows how suited slingshots are to heavy balls. Most would probably consider a 650 grain ball to be huge, I'd consider that pretty small.


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## ZDP-189 (Mar 14, 2010)

The power record should have a minimum velocity; nothing huge, just maybe something like 70 fps horizontal.


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## JoergS (Dec 17, 2009)

Can't do braces, though.

A pity!

Jörg


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