I can't say for the px4, but with all of my Beretta's, you have to cover the bullseye with the sight.
It's my first piece and it's everything I expected it to be. My aim...not so much, I just hope that when I was hammering the backstrap pin in that I didn't throw the sights off.
Also, I think I read some where that px4's shoot a bit low? According to my target it seems that may be true. Will it always do this or is this sort of a break in thing? Btw, this was at 25yrds.
I can't say for the px4, but with all of my Beretta's, you have to cover the bullseye with the sight.
Combat site hold, the front site covers the target.