When I had this problem awhile back, my instructor fired my gun and then said, "Kathy, I have good news and bad news. The good news is, it's not the gun. The bad news is, it's not the gun."
The fact that I was
consistently hitting low and left, regardless of how I stood or whether I was firing with both hands or only one, just meant that I had a very consistent problem with trigger press. For me, it took having someone stand along side me and "exemplar" the ideal trigger press before the light went on. You can read about it all day long, even watch videos or whatever, but until you have the kinesthetic sensation of pressing the trigger properly all the words won't necessarily do you any good. Get thee to a class!
pax