This shotgun has been on the drawing board for a while but only recently got built! A major downside is the mechanism for getting rounds into the chamber. It ended up as a box with columns in, so that as you move it over a hole above the chamber the shot just drop in. It works, and you can get quite a fast fire rate, but it is far from perfect. Good things are the power and... well that's about it, actually! It is powered by two matched large elastic bands (same as those on the old aircraft carrier's catapult). I had a bit of fun with the smooth and lugless Technic bits - they seem to be quite useful for devices requiring low friction.
As the handle is pulled back (i.e. the big red lump in the pictures), the 'bolt' is pulled back as well. The bolt is latched into the trigger mechanism (see pictures) and released when you pull the trigger. The ammunition can be dropped in through the hole, which is just in front of the latched bolt.
Effective range depends on the ammo, but as the gun is so powerful, I have had difficulty in finding something that was effective. I used dried peas for a proper shotgun effect, but these stop doing anything useful at around 3 metres. They make a nice "crack" noise when they hit things, though. I've experimented with wet tissue paper etc; this is quite effective, splats on impact, and is also good for making slugs. I also tested other random objects I found - Biros easily penetrate thick brown envelopes and polystyrene.
Response to Jacob:
Yes, it can handle slugs or shot with no changes needed to the design (it's tube is approximately 2 by 3 units in diameter). The "magazine" box on the top can only take the pea shot at the moment - paper gets stuck and slugs won't fit, so slugs and other ammo have to be loaded by hand. I had a go with putting chokes on the end of the barrel to control the spread of the shot, but to no avail! I probably needed to make them stronger, since they mostly ended up getting discharged with the shot...
You are correct in that there are two mechanisms, one for cocking and the other for loading. The "one triggers both" concept was too hard for me to implement on this revision so yes, two actions are needed to complete the cycle.
It looks really cool but the only thing it needs is colour coding.
I like it
October 29, 2005
From the pictures posted, I have a good idea of how yours works. I like the power and range you can get with the extended distance for the firing catapult, but am curious on the ammunition. Is it designed to handle only pellet shot or can it handle slugs? I gather from the pictures there are two pump mechanisms, one for cocking and one for loading, unless one triggers both. Nice work.