Mark
It can be that the extractor is too long, and it can also be due to a slide spec issue that locates the extractor too far forward of the breechface.
Measurements will need to be taken to determine which it is. Easy fix is to
insert a fired case under the extractor and use a dowel rod through the slide bore to force the case against the breechface. Be careful to locate the case in its normal position. Hold the slide up to a strong light and see if you can see a sliver of light between the nose of the extractor and the forward angle of the case's extractor groove. If it's bad, you can actually see the extractor spring toward the right side of the slide when you force the case back.
If there's no clearance...no light...you can remove a little material from the extractor nose to get it. It doesn't take a lot...All you need is for it not to hit. Be careful to file it at such an angle that it doesn't decrease the depth of the hook from tip to wall.