Broom rider hit on some good points.
The 1911 pistol is not a pistol that needs every Bell & whistle add on.
It needs to be accurate, you need to know how to shoot it, and it needs to work every time you shoot it.
A good working knowledge of how it functions is very important, and it can't be gotten from a Midway Catalog.
Get a good DVD or a good book or two. Getting advise from people that do not have this working knowledge will only frustrate the folks new to the 1911 platform.
Seems the first thing many people want to do is start changing parts and upgrading,
Breaking what didn't need fixing.
That said, the extractor plays a big part in a 1911 function.
While the extractor can't be blamed for every problem with a 1911
It is a good place to start if you have some of these problems.
Getting hit in the head with empty shells ?--extractor
Shells going in front of the shooter ?--- extractor
Cases going all over the shooting area ?---extractor
Stove pipes ?--- extractor
Fail to feed ?---extractor
fail to extract ?---extractor
The extractor sits in what is called the extractor tunnel on the right side of the slide looking from the rear.
It is held in place with the firing pin stop (FPS ) the FPS also holds the firing pin and it's spring in place.
The FPS is the part that you see in back of the slide. The firing pin protrudes through it.
The extractor is sometimes referred to as a little leaf spring, it puts a little side pressure on the rim of the case.
The side pressure is about 22-24 Oz. ( I believe )
With the slide off the pistol, and the barrel removed, slide a dummy round ( not an empty case )
under the the extractor hook. It should stay in place and not fall off while rotating the slide and giving it a little shake.
If it does it may need a ( little ) more tension. This can be done by removing the FPS and the firing pin along with it's spring. With care remove the extractor, clean the tunnel with a small brush and check it for dibris.
Clean the extractor. Put the extractor back in place and then pull it out about 3/4 of an inch and apply a little side pressure on the part of the extractor that is sticking out of the pistol.
( to increase tension the pressure is applied opposite the ejection port ) Do the test again.
DO NOT OVER DO IT A LITTLE GOES A LONG WAY HERE.
Re-assemble the pistol and load a mag with DUMMY empty rounds and check to see they load with out any binding against the breach face and enter the chamber smoothly. To much tension can cause the round to bind between the extractor and the breach face ( round will not be fully seated under the extractor.)
The wrong tension may cause a stove pipe also.
Shells going all over the shooting area and hitting the shooter
The culprit here in many cases it the extractor moving in the tunnel, it is referred to as clocking.
The extractor is rotating in it's tunnel like the hands on a clock ( clocking ) and not holding the empty case in the same position every time it tries to extract it. This allows the case rim to contact the EJECTOR differently
and the empty case leave the ejection port in a different arc each time extraction occurs.
The remedy for this is a new firring pin stop that fits in the the slide with a little resistance and is a positive fit into the groove in the back of the extractor.
A simple test with the pistol fully back together press on the upper part and the lower part of the extractor
at the rear with something that will not scratch the pistol. There should be no rotating or movement of the extractor.
What I have said here are some very condensed hints about the subject.
The extractor and it's proper shape and function is an in dept study, I have made some comments that may give a little insight on the subject with the hope that you may explore it further.