Here is a full size lego glock 18 I made. I won't be soloing a tutorial on this gun, because it was actually quite difficult for me, having to put a big rubber band in a small place with out putting so much tension that the gun would break.
Step 1: Blowback
This guns slide can be pulled back to reveal the barrel.
Step 2: Slide Lock
When pulling the slide back, the slide lock can be pushed up to stop the slide.
Step 3: Sights
These are the sights.
Step 4: How I Made It Work
How I made the slide work.