There is no 1986 GCA. The 1986 legislation was the Firearm Owners Protection Act. It was a good bill, repealing the more egregious provisions of the '68 GCA (Maybe that's what you meant), such as having to show ID and sign a register when purchasing "handgun" ammunition(including .22 rim fire), and removing the provisions against interstate shipment of ammunition directly to a consumer, It also provided several protections for gun owners, such as the ability to transport firearms from one state where possession of them is legal to another where is also legal, never mind the laws of states or localities in between (with limitations on the conditions of transport).
The one bad feature, and it's truly awful, because it was the first outright *ban* of a whole class of firearms for civilians, was a last minute (literally) addition that many did not even know was in the bill and fewer yet understood. In fact it was so poorly worded it should not have changed anything, but it's being enforced as the author intended, not as the law actually reads.