This a modern take on one of my favorite guns I've ever made. If you think it's just another generic firing pin gun, then don't leave just yet. This uses a very unique pin. Basically, all it is is a blue rod sticking out from between a bottom and top rail with gears to keep it on on either end. This can make a gun very compact and better looking, and more realistic.I seriously recommend building this gun. This idea will almost certainly work with bullpup guns too! Maybe you can get a few ideas, or maybe you can just have lot of fun with it.
This gun is really fun to shoot!
Pros:
Decent range
Fun to shoot
small and packs a punch
Easy to load

Cons:
Gun is still not quite perfected; the pin may go under the trigger once in a while causing the gun not to work. Easily fixed with pulling the pin back a bit.
Handle isn't that comfortable

Get building! I'd love to hear some feedback on this gun.

Step 1: Outer Body

A panel that goes on the outside of the gun. Follow image notes.

Step 2: Handle

The handle of the skorpion.

Step 3: Inner Panel

An inner panel..

Step 4: Internals

The stuff that goes right in the middle.

Step 5: More Panels

More panels/internals.
The pictures in this step aren't very clear on what they want you to do, so I will go through them step by step.

Picture 1: Make this and clip it to the blue rods on the end so it lines up with everything else.
Picture 2: Make this and do the same with this as the previous piece but put it so it lines up with the other side of the magazine.
Picture 3: Do the same with this as the other pics.
Picture 4: Make this
Picture 5: Get a small piece of tape and a green rod
Picture 6: Stick it on the end of the tape
Picture 7: Put that piece from before in and make sure it lines up with the trigger
Picture 8: Put the green rod on the hole, and put the tape on the side.
Picture 9: Take the tape off of that specific part; you will need to have that hole accessible.

Next step!