If i remember correctly, they were illegal to produce, import, and sell after the date in enactment. The weapons etc. that were made/sold before the ban were OK to sell.
All ammo feeding devices that held more than 10 rounds could still be made but had to be marked something to the effect: "For police or government use only" and could only be sold to uniformed civilians and the military. A citizen of the United States of America could own a "high capacity" (standard capacity) magazine as long as it was made before the date the stupidity was signed.
The law also made in necessary for gun shop owners to increase prices on their stock of pre-ban magazines to 500-600% in an effort to stick it to their customers despite no change in the cost to them. Most places I know had a supply of "pre-ban" magazines that lasted through the ban and long after it ended. The supply was there the whole time.
The law also required those of use who were never into pistol grips on a rifle or bayonet lugs and all that to immediately go out and buy one....not for any reason we could really put our finger on but just because we thought we needed to. Now that the ban is gone, I sold all mine and went back to lever action rifles and double barrel shotguns - the kind of guns I was always into.
Finally the law required you to become a card carrying member of the NRA and get a bumper sticker that says, "Charleton Heston is my President" - a membership which you let lapse during the Bush years because you let your vigilance get lazy and you found some innocuous reason to not like the NRA.
All in all, when you look back you see how stupid the ban was and how stupid our apathy got when the ban ended.
The only good thing that I remember was a few months later when
the demacrats an Dan Coats stopped laughing in victory when the
Gun lawyers figured how to sell me a AK47 without a bayonet lug, an
a one piece grip an stock called a MAK90....things just didn't work out
like they thought.