How do i take off the front sling swivel on my busshy M4 upper?
Two ways to do it.
The first is to use a very small punch and punch the middle of the rivet. The rivet will be forced back(de-faired) and can be reused.
The second way is to use a 1/8" drill bit and just remove the flair, then drive the rivet out. This way will require you to buy a new rivet or roll pin to re-install the swivel.
P.S. On my full float DCM rifles, I install a small sleeve(park'd) and a roll pin. It makes the ears look like they belong on the rifle, due to the installed sleeve.