My first gas operated gun (well, my first complex gun). It's not fully realistic, for example, the trigger group is weird and the selector uses precision bugs from 200 Hz. It's very laggy, and:
"If you don't have three jams per magazine, you get your money back! 

 "
It jams every three bullets, and maybe the first one ejects without even firing or the shell jams the gun.
To fire:
Real mp7s have a reloading handle at the back, but i didn't know how it was exactly, so I've added that little light-blue handle. 
Load the mag or press G for autoloading, and after it's fully loaded press H (if you used the automatic loader). Cycle action by moving the handle all the way right and RELEASE it, and then select fire mode and drag the trigger all the way.
Also, to release the mag, the handle was in the other side, so I reversed it
L for lag reduce
Rate and comment (and help me 

 )! I just wanted to make something different. please give me ideas on how to improve this!
P.S: I was inspired to build this gun by 
Half-Life 2. My favorite game so far 

 .
v2: Buttered some trigger group mechanisms (yes buttered 

 ) and fixed mag ejector and safe mode. Please, if you'll use semi-auto mode, drag the trigger slowly.