Looking at that photo I would say that the machining of the slide for the extractor is way out of spec but the gaps you're seeing from the rear of the slide really have very little to do with the mechanical accuracy of a 1911. I've seen plenty of govt. issue .45 pistols with more slop than that that will chew the center out of a target. The critical thing is the fit of the barrel to the slide when the gun is in battery. If the barrel and the slide lock together in battery and the sights are aligned on target it will shoot where it's looking. Tightening the slide/frame fit won't make much difference if the barrel is good and properly fitted. But what you have is substandard workmanship on the part of the manufacturer. If it won't shoot then there's other issues.