I had to take it to a gun shop cause i tried to use a punch and do it myself. from what ive been told its kinda like a glock where the dove tail is so tight that you need a specialty tool, its a screw that clamps on to the gun and pushes the sight. i dont recommend using a punch(unless its Brass) cause you will dent and gouge the crap out of the sight. im no expert this is just my experience.

What model do you have G and the F have the same sight type the D model the sight is much wider so its easy to move then the F or the G there is a tool you can buy to move these type of sight they are very tight I use a little oil on my sight it need to be move very little most Beretta shot to the low left when they're new or should I say almost all new hand guns. Your right there is nothing on the manual except that they can be remove. Good luck and ALWAYS be SAFE