This gun is basically mydifferentusername's design, except for 2 things: the color, and the fact that hammer doesn't go down when the slide is pulled back.
Step 1: Magazine
The magazine has some holes in it not because I didn't have enough Legos.
Step 2: Slide
When you back the slide of the gun, it will reveal the barrel.
Step 3: Slide Lock
Unfortunately, I didn't have enough room for a slide lock, so the slide lock isn't pointer finger.
Step 4: Extra
The muzzle can be taken off to add something like a suppressor.
Step 5: How U Do It?
If you want to build this gun, I suggest that you start with the handle, then the bottom of the slide, and then, the slide, then the mag. Part of the slide you want to make the shell ejection port. Make it by the handle, but not exactly over it.