9" nails as ammo: New slingshot pumpgun!


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JoergS
December 24, 2012, 12:02 AM
Here is my latest work... a repeating slingshot crossbow, shooting 9 inch nails.

This is in continuance with my Chu-Ko-Nu based design line. This time, it is bigger than the pencil shooter, but a lot smaller than the chest mounted spear launcher.

http://i14.servimg.com/u/f14/16/32/46/92/9inch210.jpg

The ammo is - nine inch (23 cm) nails. Those are cheap, about 8 Euro-cents a pop (10 Euros for 120 of them). Of course you have to cut of the head, done in about one minute.

http://i14.servimg.com/u/f14/16/32/46/92/9inch110.jpg

The repeating action is done by pressing the butt against the chest and pulling back with both arms, like in a rowing machine. This is needed as you need a lot of draw force to throw the heavy nails - each weighs 76 gramms (1276 gr). The magazine fits ten of them.

http://i14.servimg.com/u/f14/16/32/46/92/9inch310.jpg

With a bit of extra effort, you can very easily enhance the tip by sharpening it. I even hardened the tip of this one.

http://i14.servimg.com/u/f14/16/32/46/92/9inch410.jpg

It works great. I may add more rubber soon, but already this is very effective. Like a Chu-Ko-Nu, but more compact and with a trigger!

Here is the video:

http://www.youtube.com/watch?v=95Xm-YT4FZ0

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JShirley
December 24, 2012, 08:40 AM
Neat. Wondering how far they'll go accurately.

John

heron
December 24, 2012, 02:40 PM
Looks like you've reinvented the Chinese repeating crossbow. I'm always delighted at your inventiveness.

bikerdoc
December 24, 2012, 03:46 PM
Intriguing idea.

sawdeanz
December 24, 2012, 04:59 PM
Looks like a lot of fun!

snakeman
December 24, 2012, 05:17 PM
Sweet!

Mauser lover
December 24, 2012, 05:24 PM
Wow, rubber band gun of doom...
What do you plan to use this on? Is this some kind of firearm replacement for someone who lives somewhere it isn't possible to get a firearm?
If so... Looks like it would be a good replacement!

Centurian22
December 24, 2012, 05:32 PM
Very interesting! I also am interested in the accuracy and range of it?

JoergS
December 25, 2012, 01:09 PM
Here is the video - sorry for the indoor filming, lots of rain.

http://www.youtube.com/watch?v=95Xm-YT4FZ0

The weapon is very good for distances up to 15 ft - then the nails will start to tumble. If you use front heavy bolts (wooden, aluminum or carbon shaft, steel tip), then the effective range is more like 20 yards.

I think this makes a good self defense weapon, much quicker reloading vs. a single shot crossbow and very intimidating. One hit with a nail in the belly, and a burglar/attacker wants a doctor more than anything else in the world :)

possom813
December 25, 2012, 01:32 PM
JoergS, that is about the neatest thing I've seen in a while.

I hope you don't mine if I share your video on facebook.



Also, what are the bands that you are using for this nail gun? I still have a few weeks before school actually starts, and I'd like to attempt something like this to shoot in the backyard.

thepumpfaction
December 25, 2012, 01:38 PM
I saw this vid! I subscribed to you on youtube. I'm a huge fan! You build some amazing things.

JoergS
December 25, 2012, 02:45 PM
I hope you don't mine if I share your video on facebook.

Also, what are the bands that you are using for this nail gun?

Go right ahead an post it on facebook, that's fine with me.

I used Thera Band Gold, 6cm x 13cm, two bands per side (looped). Since the video was shot, I added another identical band in Thera Band Blue, effectively making the bands 30% stronger. This is pretty much the limit of the material (wood is groaning under strain already).

XDJ
December 25, 2012, 06:56 PM
It's a good thing it only holds ten "bolts" because we all know that 11 would just be too dangerous.

I love your videos and slingshots. Keep them coming.

Dr. Sandman
December 27, 2012, 09:39 AM
You should submit this idea to industry. There are many people out there who would buy this.

19-3Ben
December 27, 2012, 09:42 AM
There are many people out there who would buy this.

Trent Reznor could make a fortune selling them!!!!

19-3Ben
December 27, 2012, 09:47 AM
The weapon is very good for distances up to 15 ft - then the nails will start to tumble.

Might there be a way to add fins to the back, like an arrow to help stabilize for longer range?

USAF_Vet
December 27, 2012, 09:32 PM
As always, I love your stuff.

Could you put your patterns in a PDF format for download so we can try making our own?

JoergS
December 28, 2012, 01:20 AM
The dimensions of the weapon depend very much on the size of the nails. A pattern would really only work if you use the exact same nails I have. It is not likely that this will be the case.

The weapon is very easy to understand, though. Only two moving parts - the trigger/sear and the slide.

As I said in the video, fins aren't the key to a stable flight. Front heaviness is. Fins are important for bows, as they are needed to overcome the archer's paradox (the arrows wobble after the shot). For a weapon like this, there is no such effect as the acceleration is very linear.

7mmstalker
January 1, 2013, 07:27 PM
Very good engineering, an effective weapon built from common materials, using basic skills.
Joerg, my compliments, true strength of intellect and inventiveness.

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