I think youve bought a lemon. My GI has reliably shot Gold Dots and Remington JHP's flawlessly, with the stock spring.  Youre problem can be fixed Im sure, but this is something I would make Springfield fix.

My Springfield has all sorts of issues like this.  Mine DID go back to Springfield.... they "fixed" a sear/safety issue.... but did not address the reliability issues at all.

New wilson "bullet proof" extractor and Wilson 18.5# recoil spring... and she purrs.

That GI model does not have a lowered or flared ejection port.... to remain ture to form.  I have read some will eat anything, and some are finicky as hell.

The only way an 18.5# rated load recoil spring could cause failure to fully eject is if the gun is being limp wristed.
An extended ejector as pictured by SGB is a good idea. Pick one up from Ed Brown or Brownells.

It doesn't sound like an extraction problem, but you might as well take it out and clean out any carbon build-up to be on the safe side of ruling things out.

If the extractor holds the case rim firmly I would say it's not the extractor and agree that your problem IS your "ejector".  On a full sized government model just about all manufacturers use the standard short ejector.  If your gun does not have a lowered ejection port, this compounds the problem.  With the short ejector the case rim hits the ejector when the slide is almost at the end of it's recoil cycle.  If you install a stronger power recoil spring you compound the problem because the slide decelerates sooner causing the casing to hit the ejector at a slower speed than it should and the strong recoil spring causes the slide to go back into battery before the empty casing has had a chance to clear the port.

With all new Government Models I would adjust the extractor tension, install a stronger recoil spring so I could shoot hot self defense loads, and install an extended ejector.  I would do all this before I ever put the gun in service.  If you really want to get picky, you can tune the ejector to get the empty brass to land exactly where you want it to.  That is done by changing the angle on the face of the ejector.  I have done this a few times when I have had WAY too much time on my hands.

Hope this helps,
MadDog

The recoil spring in the 1911 has to be matched to the intended load for top performance.  A spring that is too heavy for a given load will cause problems.

Settle on which load you want to use (target, GI Ball, heavy hollowpoint, etc) and work on the reliability from there.  If the brass ejects more than 10 feet (or so) from the shooter, the spring is too weak, if the brass dribbles out of the gun, or gets hung up, the spring is too strong. Springs are available in a range of strengths in 1/2 lb increments.

A GI ejection port will work fine, but can be rough on brass if you are a reloader.  The case will impact the lower edge of the slide and get a good dent.  This leads to cracked casses after several reloads.

The gun should work fine with the standard ejector.  There can be issues ejecting a live round with extended ejectors, something to watch for.

. tag

18# won't be a problem, but a 22# might batter the extractor too much.