I built this little hammer gun after seeing this guys hammer pistol...
...and decided to make my own as I wasn't too fond of it.
It's a 3 layer, true trigger design. I did try to add a grey connector magazine however it didn't quite work. It can potentially fire 3 different types of ammo but I prefer the grey connector - green rod as it is the easiest to load and has very good range and accuracy with two #64 rubber bands doubled up.
I messed up on tagging the photos, sorry.
It is probably really easy to make from the photos