So, this is my M4 as it looks today.
Still to come are a Ergo grip, Magpul trigger guard and a CTR stock.
This is the ebaybanned $40 D'Boys RIS btw and it does indeed wooble without modifications.
Roughly about 1mm to left and right.
I applied some scotch tape to the groove on the inside of the top part of the RIS which sits on the barrel nut and now it's solid as a rock.
But for some reason my bolt catch doesn't work properly. Well, acutally it does when I push down the bolt catch with my finger, but the pin or the spring inside the magazine seems to