I see this all the time and especially with LE Guys transitioning from 9mm to .45 ACP. "Hey I Need New Sights On This 21 Glock"! No you don't you just have to shoot the weapon to become proficent with it and that entails practice and more practice. You can't expect yourself to be able to shoot any weapon be it Long Gun or Pistol by shooting 100 Rds. every 6 months when you qualify.
Everyone's body makeup is different and unique when dealing with recoil:
RECOIL:
Definition of RECOIL
intransitive verb
1
a : to fall back under pressure b : to shrink back physically or emotionally
2
: to spring back to or as if to a starting point : rebound
3
Examples of RECOIL
1. We recoiled in horror at the sight of his wounded arm.
2. He recoiled from her touch.
3. The rifle recoiled and bruised my shoulder.
As can be seen the observation in just about all examples show a physical response!
Anticipating Handgun Recoil by trying to eithr deflect or defer is just your body's natural response to an action that it feels is unnatural. So our Mind and Body work together to try an compensate for this action.
When I have an individual who thinks it is the weapons fault of not shooting where aimed I usually get out the Laser Bore Sighter and show them the sights on the weapon are pretty much Nuts On.
If YOU are shooting your Sigma to the Left try aiming the impact distance to the right. Same thing if you are shooting your weapon Low just aim higher to bring your POI Up.
Since The S&W Sigma uses conventional rifling you are blessed with being able to shoot Lead. Either buy some lead reloads or reload some Mid Range Rounds and just shoot and then shoot some more. I think 95% of all the Left, Low complaint will resolve themselves without sending your Sigma back to the factory or replacing your sights.
Go shoot that Sigma tomorrow if not sooner and shoot it regularly and you'll find your Sigma to be a very accurate Handgun right from the factory.