I will post this because I think it applies here.

I have trained a lot of people with Glock pistols. Every time I have ever been on the range with this certain group of personnel someone either told me "something is wrong with my gun" or "my sights are off".

So far I have not encountered a single Glock pistol that had something wrong with it nor have I ever came across one that needed a sight drifted.

Every single one of those guns complained about shot just fine in the instructors hands.