[ARCHIVED THREAD] - Receiver differences Mossberg 500/590

Posted: 12/29/2014 11:08:01 AM EDT

I know the trigger guards, safeties, barrels, and feed tubes are different,
But, Are there any differences in the actual receivers or internal parts?
Or any other differences or machining processes between the two?
Not talking about external finishes like blueing or parkerizing.