RE: xtrema shoots to the left?
It's a very common problem with the beretta Xtrema. Most of is has been corrected with the Xtrema 2.
Shoot the gun from a bench and have some one else shoot it also. This will take the fit part out of the equation. Aim the gun as you would a rifle. Shims will adjust the POI some but, not as much as needed with the ones that shoot far left. If the gun does in fact shoot to the left from a bench with more than your self you may want to contact Beretta.