ok, so apparently alot of people don't know this glitch (and it's one of the very few glitches still left in junk flea) so i've decided to refresh your memories ^^
i don't take any credit for this, so please don't flame, etc.
Ok, so find this tank:
What you want to do is start out on the tank that i am standing on and face so that the tank i am pointing at is to your right.
Next, you want to move to the right and "fall" into the area that i am pointing at. If you did this right, you should be partially into the tank.
Then, move to the right until it seems that you clicked into the tank.
Hooray! Now you can shoot at people coming that way.
Result:
Please thank me if i helped.
EDIT: Before people start telling me i'm an idiot for not blurring or removing the names, oh well ^^ sorry.
EDIT: The random floating metal bars and stuff can't be shot through, and are kind of annoying.